FEFSTD-E28/2S
20 AqJst 1991
SUPEI?SEDItG
FED-STD-F128/2A
20 April 1984
(seeNote)
●
FEDERAL
STANDARD
SCREW-THREAD
STANDARDSFOR FEDERALSERVICES
SECTION
2
UHIFIED
INCHSCREW
TMEADSFORMS
UNANDUt14R
THREAD
,0
●
This standardwas approvedby the Ckxmnissioner,
Federal
SupplySsrvice,GeneralServicesAdministration,for the
use of al-lEkderalagencies.
AMc
APEA1’ms
m
DISTFUW1’ION~
A. -Approvedforpublicrelease; distrikxkionis unlimited.
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This FederalStadard is issuedin lwsel.eaf form to permit the insertion
or removalof new or revisedpages ard sections.
All usersof FederalStadards stculdkeep them up to date by inserting
revisedor new pages aa issued* removingsu~seded ad canceledpages.
w
ad revisedpages will be issti tier Change Noticeswhich will be
nunberedcmsecutively ad will bear the date of issuance. ChangeNotices
shouldbe retainedd
filedin frontof tk stadard until such time as they
are s~rseded by a reissueof the entirestardard.
EtnawmI
,., ,
This secticnwas develqed b provideUnified
Inch Screw Threada br the
FederalServices. It Q
formxly kmwn as “UnifiedThreadI@rm ad Thread
Series for Bolts,.!kretrs,
Nuts, Ta~
Boles aM GeneralAppli=tions=.
EEWS1’&H28/2Aws a Ca@ete revision of FR%7TWB28/2 dated 31 March 2978.
It added the nsiterial
previouslyidentifiedas FfD-sTD-H28\3dated
31 March 1978,which was knownas “UnifiedThreadaof SpecialDianeters,
Pitches,.
ad Lengthsof Engagenx2nt”.&terial franAppmdices A3 ad AS of
FED+IWB28 dated 31 March 1978 was revisedad tecaueApprdies A and B,
respectively,
of FBD-STD-E28/2A.
.,,...,, .,,,....:, ,,
,. .,.. .. .... . ,.,
FSD-51WH28/2Awas preparedby tk CefenseIndustrialSup@y Center ~-IS)
and inoxpxated the AmericanNeticnalStardsrdb’ Unitied Inch Screw Threads,
WI B1.1-1982. Significzmtchanges fran the previousissuesincltiedthe
following
:
(1) Added UNR, externalthreadform with mandatoryroundedrrnt.
(2) Sevisedtolerancerequirementsfor lead and flank angles.
(3) Added requirementstir controlof surfacetixture,cknfers, ad rolled
threadled-ins ad run-outs.
(4) Added requirementthat inspectionmethods for acceptabilityare in
aaxmdance witb FER51D-H28/20.
●
FED-STWH28/2B incorporatesthe AmericanNationalStandardfor IJnif
ied Inch
Screw Threads,A.SNZB1.1-1989which superssdsdA!W B1.1-1982and its
dated 20 April
suPPl~t , At=z
B1.1s-1984. It @ates the FEE.S’K)-H28/2A
1984 ad improvesthe legibilityof the tables. ~ndix
C was .dded to
provideinfonnaticmalxmt tk obsoluteAmrican Naticna3form threads.
ii
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FED-sl’D-H28/2s
SETIOW 2 - UnifiedInch Screw ThreadsUW ard UNR ThreadFOrIUS
1- ~
~is ~tion providesthe standardfor WIified inch ~rew
threadsto be used by the FederalServices.
1.1 ,Qm.itations.(My uw ad UWR screw threadsare cmered in this
section. Ebr UNl threads (axkrolledexternalthreadrouded root with
increasedbasic minor diamter ) see FED-STD-H28/4(MIL-S-8879
). For UN!
threads (miniaturethreada)aee FEO+lD-H28/5.
1.2 Application.
1.2.1 UW form screw threads. The uw threadis intendedfor generalpurpose
fastening~~i-G;
Its externalthreadroot may be either flator
rourikd.
1.2.2 UWR form scrqg i+reads. The UN’Sform a@ies mly to external
IS the sa.m as that of the external UN thread except
threads. Y&~l~&n
that the rcot is requiredto be rourxled.UNR threadsare appliednmt often ‘m
high volum annnercialfastenerthreadsproducedby rolling.
Nnz:
The uardatiryroumiedrcot of the UNR threadgreatlyreduces
the wn02ntration of stress,knee increasesthe fatiguelife
of threadedpr ta.
Referenceddcmnrents.
2. ——.
—
2.1 Governxren~uMications.
The issuesof *
following&amenta in
..—
effecton the date of—invitationfor bids or rsquestfor prqosal km a part
of this standardto the extent ~cified &rein.
Federal
..——-— Stadards.
FElE71EH28/1 - Nxrenclatue, Definitionsand Letter Symkmlsfor
Screw Threads
FED-S’IEE28/6- Gages ti Gaging for UnifiedScrew Threads
FED-SlWS28/20- InspectionM?tkds forAcceptabili& of UW, ONR,
UNJ, M and Ml Screw-Threads
(Activities
outsidethe FederalGmernnent my obtaincopies of Federal
specifications,
stardards,and ccaurercial
itemdescriptionsas outlineduriler
GeneralInformationin the In5ex of FederalSpecifications,
.%an5ards,ad
Crammsrcial
Item Oescriptions. The Index,which includescumulativebi-nnnthly
SU@SIEntS as issued,is for sale on a subscriptionbasisby the Superinten+
ent of Dccunenta,U.S. GovernmentPrintingOffice,Washington,IX 20402.
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FIm-s13H128/2B
(Singlempies of this standardand other F&eral specificatims, standards
ad cwmercial itemdescriptionsrequiredby activitiesoutsidethe Federal
@vernment for biddingp~ses
are availablefrcxnthe GeneralServices
AdministrationSpecification
Section,Ftxxn6654, 7th ard D Streets,S.W.,
Washington,CC 20407;telepimw?(202)708-9205.
●
(FederalC%vermrentactivitiesmay obtainaypiesof F@deralstardardization
documnts, ad the Indexof FederalSpecifications,
Standards,and (kxnnercial
Item Eescripticmsfran-est?bliskldistribution@nts in theiragencies.
)
2.2 Other publicatims. ‘Ills
followingdocummts form a part of this
starxlard
to the extent~ified
herein. Unlessa specificissue is
identified,the issue in effectm date of invitationfor bids or requestfor
propaal shall apply.
Ameri-
Watimal Standards.
?@E El.1-1989 - Dnified Inch Screw Threads (LIW
ad ONR Thread
mm)
AMI/ASMZ B46.1 - SurfaceTexture- SurfaceFImghneas,wavinessand
Lay
(A@icatia for rxpiesshouldte a&3ressedto the AmericanSocietyof
Wchanical Engineers,UnitedEngineeringCenter,345 Eakt 47th Street,
Wew York, WY 10017or the ArericanNatimal StsndsrdsInstitute,H West 42nd
Street,Wew York, WY 10036.)
3. Definitions. The terms a~licable to this standardare definedin
EEEsm-B2&/l .
4. Generalrequiremnts.
4.1 Screw threads. Unifiedinch screw threadssbal.1@ in ,arxxx&ce with
ASMS B1.1-1989ad this FederalStarderd. Qily Stam3ardSeries UnifiedScrew
l%rezxls,
listedin Table 3A of ASME B1.1-1989,shallbe used for new design for
the FederalServicesunlessprior approvalhas been grantedby the prmxreuent
autlxxi~ to deviatefrom them. Coxae ad fine threadseriesare preferred.
4.2 AcceptabilityScrew threadinspectionmetl-dsfor acceptability
shall
lxsin arxxxdancewi~ E’ED-SD+328/20.The requiredgaging systemshallbe
specifiedin accordancewith that standard.
4.3 Gaqes ad gaginq. Gages and gaging shall be in accordancewith
FE&51D-H28/6.
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●
5.1 Diamter~itch mubinations. When standardsize screw threadsreferred
to..
in.4.l.canno.t..lz2.
used,..
tbe.designez..kcdddd
chaos.e+referred.siz=s
of.ti’yeads
lisl@ in ‘1’@.le
3B of M
B1.1-3.989.lf this is,not pssible,
onsideration slxxidbe gi.yento the folbi.ng sub-paragraphsin the choi~ of
thread.
5.1.1 Preferredrun-standarddiameters. tb?neverpossible,‘& ~
diamter stwuldbe selectedEran seriesof dimretarincrementsas follows:
Diauk?ter
range
First choice
increlent
Second&sire
increumt
inch
inch
inch
0.05
0.1
—
.0.05
0.1
0.25
0.5
0.25 to 0.6
stove 0.6 to 1.5
abve 1.5 to 6.0
stove 6 to16
akove16w24
0.25
0.5
1.0
It is rewmrendd that dianetersless than 0.25 inch anform b the standard
sizes aa there is virtucdlyno necessityfmr the selectionof a diameternot
inclded in *
sizes. A.1.eo,
i+? ax.rseand fine thread series provide ample
choiceof ‘diamstet-pitch
ccmbinatkms.
5.1.2 Preferrednrn-standardpitches. 14kneverpossible,ti pitch should
be selectedfrcxoaae of the following: 40, 36, 32, 28, 24, 20, 16, 12, 10, 8,
6and4threada per inch. Intermediatepitdieaalx3uMb used only when
absolutelynecessary. Pitches ccarserthan 4 threadsper imh are not
recxxmnmded. The curves slx%n in Figure 2.B.2of -ix
B cover the
practicaldiaueterlimitssuggestedfor each pi@.
5.2 Thread class selectia. StandardUnified threadclassesand their
applicat~ection
4 of rk5MEB1.1-3989. when selectinga
threadclass,considerationskxd-d firstbe given b & use of a class ~
externalthreadwith a.c3.aas28 internalthreadsince theseclassesare
designedfor generaluse. Before specifyingclass 3M3B series,it met be
consideredwhether the additionalproductkm mst, necessaryfix the tighter
fit and toleranm is justified. If a fit Imser than the sbndard class NIB
is required,* rm~referred class IAR may be .spsifiedfor an external
threadof 16 threadsper inch and marser. This specialclass ombines the
largerallowanceof the old AmericanNationalclass 1 threadwith the Unified
class n toleranm. See 5.2.2 for class N al.lmenm.
e
3
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I
FEFS1’Mi28/2B
5.2.1 Replacementsfor &solete AmericanNationalthreadclasses. When
threadsspecifiedwith the obsoleteAmericanNationalthreadclassesare to be
replacedby unifiedthreads,the followingguidelinesare provided:
●
a. AmericanNationalclass 1 coarse threadsizes (tK!-l)
is approximatelyequivalentto Unifiedclass Il@l series. C3.aSs1 fine
threadseries (N&l) is approximatelyequivalent
dirn?nsionally
to
Unifiedclass 2A/2B series. StandardUnifiedseriesthreads
should~, consideredprior bJ approvalof replacxznent
by rzmsta!xiard
threads.
b. Amrican Natirnalclass 2 rrarse threadseries (K-2), 8 thread
series (EN-2)
, 12 threadseries (12N-2)
, 16 threadseries (MN-2),
ad extra fine threadseries (NEF-2)are mxt nearlyequivalent
to Unifiedseries13N2-21@, 8UN-2@B, 12Ut+2A/Z, 16UN-2A/Z
ad UNEF-2A/Z3,respectively.Class 2 fine threadseries (W-2)
is approximatelyequivalentdimensionallyto Unifiedclass 3A/3B
but the use of class 2?@3 series should be omsidered
series,
prior to approvalof replacementby class 3A/3B.
c. AmericanNationalclass 3 seriesK-3, NY-3, FIEF-3,
EN-3, 12N-3
and 16N-3 are nest nearlyequivalentb Unifiedclass 3 series
UN2-3A/3B,UNF-3A/3B,UNEF-3#3S, 8UN-3A/35,12UN-3A/3Bad
16UN-3@B, respectively,
d. There is no Unifiedthreadclass equivalent@ the old American
Nationalclass 4 which requir~ sel~tive fit of ~ts due ti the
pxsibility of interference.
“
●
5.2.2 Threaddbwance~bleranoa
. Mbwances and tolerancesspecified
for sti~~
Unifiedthreadc.la.sses
are descritedin Secticn5 of A94E B1.1-1989.
Ebr the spscialexternalthreadclass N, tolerancesare the sane as fir class
3A and allowsnce
s are as follows:
Threadspr
inch
I
Class lAR allowanm
inch
0.0018
0.0021
0.0024
0.0028
0.0034
0.0044
0.0064
16
14
12
10
8
6
4
To ccxrplerrent
paragraph5.6 of ?ENE B1.1-1989,reccnmnded tap drill sizes *
hole size limitsbefore threading,for differentlengthsof engagement,are
incltiedin A-d ix A.
4
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FEo-mB28/2E
5.3 -tion.
Designationof Unified screw threadsis in axordanoe
.—
with section6 of AWE B1.1-I.989.tkini.na.l
size shall be stated in dec~.
Tk symtol~
is appli*e
to any thread:
., .......
.
. .. .
(1) having the taaicUnified thread form
and
(2) with limit5based upon Unified formulations
arrl (3) which is not in the s~ard
ASM?,B1.1-1989.
serieslisted in Table 3A of
5.4 Limitsof size. See section8 of IXiMEB1.1-1989for limitsof size of
stardardand preferrednm-a~ard
threadsand km inbrmation used hr
calculationof nm-stardard threadsize limitswhich are not tabulated. For
class m, calculateas br clasa IA except allowanceis tabulatedin 5.2.2.
The followingexanpleillustratest& prccedurenecessaryto alcul.atethe
limitsof size of a mn-starrhrd thread;this follow-s
the outlinesin tablesIA
and lB of ?x?!MF,
B1.1-1989:
Externalthread,2.500- 28UtG-2A
Lengthof engagement,1 imh
Maximm major diamter = Mxninalsize - a319wlnce
(section13 of ASkE B.I.1-3989)
= 2.5000- 0.0014 (frantable 32 of X!& B1.1-1989)
= 2.4986
Mininnnn
mjor diameter. Mdn’nunmajor diameter- tolerm%e
(section 13 of ASME B1.1-1989)
= 2.4986- 0.0065 (frantible 31 of ?@4E B1.1-1989)
= 2.4921
kiaxinwm
pitch diamter = Maxinnnn
major diamtir - h
(table6, CO1. 13 of FtiN8k1.1-1989)
= 2.4986- 0.0232 (rourdedfrcxnO.023197)
= 2.4754
Minimumpitch diameter= M&mum pitch diamter - tolerance
(section13 of A94E B1.1-1989)
2.4754- 0.0056 (frantable 34 of XiFIEB1.1-1989)
= 2.4698
5
Naninal (mximmn)
minor diamter
WXimm major diamter (table6, CCL 15 of ASMS?B .l-1989)
= 2.4986- 0.0387 (rouded from 0.03866)
= 2.4599
=
5
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Fm-sImB28/213
Internalthread,2.500- 280N5-2%
(b mate with the atrm thread)
Minb.nn&r
diaueter. ~
size - 2%
(table6; ml; IS ofiU3MEB1:l-19S9)
= 12.5000-0.0387 (roundedfrom 0.03866)
= 2.4613which is rcundadti 2.461
!.laximum
minx diaueter= Minim.nn
minor dianeter+ tolerance
(sectim 13 of ISQZ B1.1-3.989)
= 2.4613+ 0.0063 (frantable 39 of ASME B1.1-1989
for lengthof engagementof O.43)
= 2.4676which is rourdedW 2.468
Minimumpitch diameter= Nminal size - h
_B1.1-1989)
(table6, ml. 1! of =
from 0.023397
= 2.5000- 0.0232 (rourried
= 2.4768
Maximumpitch diameter= Mininunn
pitch diameter+ tilerance
(sectirm13 of ~
B1.1-1989)
= 2.4768+ 0.0073 (frrxn
tie 37 of ASME B1.1-1989
= 2.4841
Mdna.1 (minim@ major = Minimum size
diameter
= 2.5000
Factorsused in the design of threada,particularlyspecialthreads,are
presentedin -ix
B. It is to be noted thatdeviationsfrcanstiard
~ler-s
for major diamter of the externalthreadard for minor di.amterof
internalthrerdmay be necessaryin order to arriveat th optimumdesign.
5.5 Surfacetexture.
sbiillhave a smoth finishend te free firm flawsand
5.5.1 l!he~
other defects,such es fins,nicks and burrs,thatwould make them unsuitable
for * purpae intended.
5.5.2 Wdonanahip shall be rrmaistentwith the &Jeranms specified
herein. Surfacetextureof threadsprodumd b this stamiardshallnot exceed
100 microincharit.beticalaverageroughness (~) for at threads ~
63
microinch(~) for rolledard groud threadsin arwith AISI/M?4Z
B46.1.
WE:
c2xrse ad fine pitch threadswith xoughsurfacetextureare tmre likely
b cross-thread.Threadswith chamferedenteringends have the least tendency
to cross-threadwhen assembledwith pwer tmls.
6
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E’Eo-sTrM28/2B
5:6 Chrunfer.
5.6.1 All enteringends of externallythreadedfastenersand threaded
cqenti
_
have 45° Chamfecs (approxhately)frcun
minor diametersor
slightlyhelm mimr dianeters,unlessotherwi~ specified.
5.6.2 All enteringerds of internallythreadedfaatenersand threaded
crspnents shall have nminal 900 -120° countersinksb or slightlygreater
than the threadnjor diaueters,unlessotherwi= specified.
5.7 ~lled threads.
5.7.1 C4xrple&lyforud threads. A carpletelyforned thread follows
the
threadprofile,w~thi.nthe toleranceznne over an axialdis=ce of cne pib=h
(seefigure2.1).
lete formedthreads,
5.7.2 InaaT!P
5.7.2.1 The lead-inthreadis measuredfran tk ed of the product to the
start of the firstcaupletet.hcead
where the mjor dianeteris equal b the
minimumati~e
major diaueterad the threadrcot is egua.1to the maxiunnn
minor diauetir. This slrxddnot exceed 2P (seefigure2.2).
5.7.2.2 The run-outthreadis neasuredbetweenthe transiticm@nt of the
productad the first threadroot which is anpletely formed,where th minor
diaueterequals the ue.xinum
permissibleminor diamter and the najor diam?ter
of the last fully formedthread_
the minimumpenuissiblemajordianeter.
When rcmt radius is specified,1A? last cmpletely t%rmd rcot at tk minor
dieuetermust met the reguireuent. See figure2.3 for full shank fastener,
figure2.4 for pitch diauetershank fastener,figure2.5 for shouldertolt,
figure2.6 for oversizediametershank fastenerand figures2.7 and 2.8 Jim
threafled
to hed fasteners.
6. Notes.
.—
dated
6.1 ~~rsession note. In additionbJ supersedingFED-STD-H28/2A
20 April 198~~~~-&~nt
alrn supersecies
AppendixXL of FED-SZD-H28dated
31 March 1978.
I
7
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FED-S’I’&H28/2EJ
+--
r“.’ WI?,*D
I
+
I
I
—+
—
r 6 BASIC MAJOR m
—
d UIN MAJOR DiA
—
—
—
-62
I
I
FIGURE
I
2.1
COMPLETELY
w
B.UX PITCH CU
‘d3MlN
FOUNDED
ROOT MJNDR VU
I
FORMED EXTERNAL
THREAO
LEAD THREADS = 2P UAX
w
1
t=
FIGURE
2.2
INCOMPLETE
FORMEO
EXTERNAL
WD
W SI+M
THREAOS, LEAD-IN
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THREADS
I
F131-~H28/Z3
●
+----
MAX
RUN””,
.2, ~
FIGURE
2.3
INCOMPLETE
mMPL~ ~REMS —
FORMED
FASTENER -STANDARD
THREADS,
FULL SHANK
DIAMFTER
F’=-;ETET”RE
—
-l—-
—’
d M!N M4.JORDIA
I
f~”,~fi
+
FIGURE
2.4
INCOMPLETE
SHANK
FORMED
THREADS,
PITCH DIAMETER
FASTENER
9
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FECHTE-H28/?B
~MINRuNwT=lp+w.y
--
FIGURE 2.5
FULL
SHANK
OPTIONAL
FASTENER -STANDARD
CONFIGURATION
DIAMETER,
(SHOULDER BOLT)
MAX RUN0U7=2P+0VERS12E
INCREMENT + z TAWe MIN)
COMPLETE THREADS
t-
+
km iwNw7. u=+WER SIZE INCREMENT + z Tb.N
12.
y~ 35.
!
-1/2 WERSIZE
INCREMENT
—-
NOTE :
e = 7RANs1710N TAPERANGLC
63
FIGURE
26
FULL
SHANK
MAX WNDED
FASTENER-OVERSIZE
—
ROOT MIMCf7ou
DIAMETER
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—
FElHmHu8/2s
E’::::,xT-”
—
— d UIN MAJW WA
w—–
A
——
FIGURE
2.7
FULL
SHANK
FASTENER -THREADED
‘d,
MAX RtMSCCD
\~wJTuBK%lw
TO HEAD
W4DERHEA9 SURFA~
w UAX * 2P +UAX
MAX
FILLET
RAlus
FILLET RADfus
mMFu_FE
‘mF(E4Ds —
W MINs0.6P
+ MAX FILLET
RADIuS
1-
~[z
7“
-I_’l.\
\
‘+-
TwU.D,A
.~
d, MAX RIXJNSCD
ROJT MINCM 91A
L
I
v
FIGURE
2.8
PITCH
DIAMETER
SHANK FASTENER
-THREADED
‘o
1-l
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TO HEAD
FED-STD+i28/2B
APPENOIXA
TAP DruLLsm
AmiamMmKm
SCKE SHS?,LIMI’IS
SEF?M?,
5i353WW
10. Smpe. ~is a-ix
providessuggestedtap drill sizes and
recrmmkied hcle size limits@iCable
prior b firminginternalUnifiedscrew
It
is not a mandatorypart of tbe standard. The infonrati.m
threads.
containedherein is intendedfor guidanceonly.
20.
‘hp
drill sizes.
20.1
General. ‘Ibassurethat the mirmr d~ter
of an internalthreadis
heldwithin specifiedlimits,it may be necessaryto use a reamerto finishthe
hole. A varie~ of factorsenters inb the productionof a clean, mud,
straightlmle of tk currectdiameter. For a discussionof Mae ad other
data on drillingd
@ping, referen~ my be made b “DrilledEoles for
Tapping”,a publicationof the UnitedStatesCuttinglbol 11’EtitUtd,
1230 KeithBuilding,Cleveland,~
441J.5.
20.2 !IabU2ated
data.
20.2.1 Table 11.A.1gives minor diameterlimitsand correspding
percentagesof thread for s3.2staderd series threadsup b @
i.nddiq 3.75
inch diameterfor classesI.Band Z. Teble 11.A.2 is a similartatd.e
for class
~. These tablesalso list sizes of drills that nay h expectedto drill holes
withinor nsar the specifiedminor diamter limits. Tlxsdiameterof the drill,
the probableInle size, ard the correepmiing percentagesof thred are
tabulated
.
20.2.2 ~ a drill may mxmal.lybe expectedto cut oversize,probabletde
sizesare tabulatedthat are derived franprobablenmn oversi~s, &
Mxilated. The followingis quoted fran the ~tionad
reprt: ‘... a
seriesof testswas amducted by drill manufacturers.Using six sizesof
drillsrangingfrrxn1/16” to 1“ in dianveter,
a totalof 2,808 holes were
drilledin cast iron ad steel. Regularhigh speed steeldrills ware used with
drilli.rq
equi~t
of the type normallybud in metslmrking shops.... ~
aver~e depth of kde drilledwas equal to 1-3/2 tines the dril..l
diemeter.
&aeureurantof the lmle was made at midpcintof the ds@ drilled....The
averageof the...aumlntsoversize..shows a marked increasein arountwersize
”
for drills largerthan 3/4”. For this size range reaming is recrmm&d.
12
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●
EZD-SDH28/2B
20.2.3 “Pe&eit of thretilisted in’tablei”is t& ratio“A P&&
of the
acti heightof tbred to & value O.75H;this value is the basic thread
heightof the oblete AuericanNational‘l’’bread
Profile. Since the basic
heightof a Ilnif
ied ThreadProfile ie 0.625H,the maximampercenttied
permissibleis 83.3%. Due to allnwmces ~r drills to cut oversizeor due to
lack of availabilityof drills within ~cified minor diametirlimits,tap
drills listed in tables11.A.1 d
11.A.2nBy sbw greaterthan 83.3% threads.
This indicatesthat the drill size is smallerthan the minixm.rn
threadminor
diameti arxladditional~hin~
of the hole my ha neoesearyin order to
permit
ecommlicaltapping.
30.
,Rermm’d
d
tde size limitsbefore threadinq.
30.1 Genera+. Rx short lergthof engagement,the imle diam?~ reouired
prior.to threadingslmti be held near the minimmnlimit to nnximise th&ad
height for maximumjoint strength. AS lengthof engageurmtincreases,it is
advantageoustrJincreasetbe bok di.amterfor uore e&mcunical**
with
less risk of tap breakage. Therefore,*
followingreccammdaticaswere
developed (alsosee 30.2 telow):
Lenqth of Engaq@m?nt
Upto
and
incltiing
0.33D
Atove 0.33D
thru
Abve
thru 1.S)
0.67D
Atove 1.5D tkll
0.67D
3.OD
Minimm Eble Size
—.—.
M.iniumminor
dia
MasinumEble Size
————
minx dia plus
3/2 minor die tilerarce
Mn
Min m.imr dia plus
l/4 minor dia tiler-
i+lin
minim dia plus
3/4 minor dia tolerance
ti.in
mi.mr dia plus
1,/2mina dia tilerance
Max minor dia (rein
mirsx
dia plus tolerance)
Min mimr dia plus
3/4 minor dia tolerance
Max mirmr dia plus l/4
-r
dia tolerance
(see30.2)
Fran the foregoingit will k seen that & differen~ betweenlimitsin each
range is the w
and egud to half of & minor diametertmlersome. This is a
generalrule. B’xever,the minimumdifferen~s for si~s below 0.25 in. are
equal b the minor diamtir tolerancesgiven in tables39 and 40 in ASME
B1.1-1989for lengtheof engagementto and includingO.33D. i%r lengthsof
engagementgreater than O.33D for sizes 0.25 in. ad larger, the mininucn values
are adjusted
sc that the differencebtween limits is never less than 0.0040 in.
13
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FED-STD-H28/2B
●
30.2 l’abulated
d=
Recomnmded hole size limits for stadard LJnified
a~ scam?Speczal (UNS)threadsare given in tablesII.A.3ard II.A.4.
For other specialthreads,calculatein acmrdan~ with 30.1 almve;use mi.niim.rm
minor diaueterad tolerancefran table 3B of ASME B1.1-1989,or calculatein
aaardanos-withsectian8 of ASME-Bl.q-1989ushg’ Spprcpfate toleranoefran
table 39 or 40 of lSKE B1.1-3.969for toleran~ ratioof ‘1or frrm firmlas b
Para9r@ 5.8.2 of B1.1-1989. Tabulatedhole sizes ad Imle sizes
calculatedin accordancewith 30.1 are not mrdatory unless the thread
designationstatesthe ndified minor diarreter
limitsard & designationMXl
in accordancewith paragraph6.7 in ~
B1.1-3989. If mdified minor diameter
limitsare not specfied, acceptancewill be in acrmdance with stardardminor
diameterlimits.
threads
Ncn!E: ~ed
maxinnnn
hole sizes in 30.1, for lengthsof engagsrmk
greatertha 1.SD are outsidestarxiard
minor dianeterlimits. They are not
incltisdin tables11.A.3and 11.A.4. Use of a minor diamter hrger than
standardwill result in a reductionin shear area of the externalthreadsof
the mating part. If manufacturingprocesspermits,maxinznn
hole size before
threadingskuld ke maintainedat the high eti of the stardardmi.mr diameter
limits.
30.3 Other ccmsiderations.When tappingrelativelysoft materials,
especia~--f
i.nepibch threads,there is a terdencyfir the materialto be
squeezeddown towardsthe rrmt of the tap so that the minor diameterof the
tappedhole uay .berxwre
smallerthan the diameterof the drilledtnle. It may
be necessaryto try a differentsize drill or differentstyle tap to assurea
satisfactorythread.
...
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●
—-—_—.
... . . ..--
__
.
j
m
15
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—____
.
. .. -
FED-STD-H28/2B
x
In
I-
&
II
u
0
16
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.: :,,
17
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FEESTD-H28/2B
18
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E%&SlEH28/23
—
—
—
...i
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FED-Sl’’D-E.28/Z0
—
—
J
— -
—,
—
—
—
—
I
11
●
.+
In
0
20
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Fm-s’llH128/2B
—
—
4.+—
. . ..-.
..........
—-—
#-l . . ..-..-
=i-
++.4 . . ..-.
~-++—
—
21
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....
FED-STIH128/2B
‘1
-.4..-.
—
4.+
.+-.A.
4+-.-!”.
~w%=—
.++-. . ... .
. ..4+.-.
+-
I
22
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m
II
1
I
1 !—
—
23
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I
—
—
—
—
—
_
—
—
—
—
—
—
.
—
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FED-srD-H2f3/2B
-
I
m
~
l-l
2s
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—
FED-srBH28/2B
26
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EIZ)-SIQ-H28/2H
ii
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l?ED-sTIHG!8/Z3
28
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F12?-.SlQ-H28/2B
I
~
I
I
I
1‘
I
I
i
i
I
●
.j
515Wl
2°3
N
0+
L-1
n
ii
29
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II
I
FEW5TD-H28/2E
m
1111
ii
—
I
30
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—
F311-STD-H28/ZB
0
31
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Fl?QSTD-H28/213
i
I
II ‘I
s
s
32
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I’11
EED-ST13-E28/Z3
5
.
imm
S’
---
33
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EED-S’IT2-H28/2B
‘2nsLs
11.A.3- ~
~le
size lim2fs tefore threading for different lergt.hsof e!qaqsrr?nt, stm3ard
Unifid
ad
saa? UtG threads, c3ds.se6IB and 272 (see 30.1) IJ
—
minx di=ter
Sm.iml size in fncb22
ard thteds &Er kc!)
1
Series
designatim
2
of internaltieais
PmmY
Percmd
of
tied
3
of
nueed
4
5
6
~
0-44
Ow
0.0465
83.1
in
0.0514
53.0
.07344 or M2. l-a
.073-72or h. 1-72
mc
.0561
.Osao
83.3
83.1
.0623
.0635
S?.7
32.7
.08+56 or f&. %56
.006-64or N2. ‘WJ4
.0667
.0691
83.2
83.3
.0737
.0753
53.0
52.7
.099-48or m.
.099-36or M.
.0764
.0797
83.5
03.2
.oa45
.0865
52.6
53.9
.0049
.oa94
83.4
83.5
.0939
.0968
55.7
56.2
.125-40or 242.5-40
.n5-44 0s m. 5-44
.0979
.1004
M
.1062
.1079
.232-32or w.. 6-32
.13s40 01 m. 5-40
.104
.22.3
83.8
83.1
.324
.2.39
59.1
58.5
.130
.234
a3.i3
83.1
.139
.142
61.6
a.o
.145
.356
83.1
83.8
.2.36
.164
62.8
64.0
.171
.177
.182
83.1
24.1
83.8
.3al
.106
.140
64.7
64.7
64.0’
83.1
84.1
83.0
83.1
.207
.220
.224
.226
66.2
64.7
LmP
Uw
.196
.211
.216
.220
R
Luc
2am
w
2WN
CKm
w
.252
.256
.267
.274
.279
.282
83.8
83.9
64.1
83.0
a2.5
84.5
.265
.270
.277
.222
.2s6
.ZS9
65.B
65.4
65.6
65.7
65.3
65.1
w
.307
.322
.330
.336
.341
.345
63.8
a3.1
63.1
84.1
a3.B
83.1
.322
.332
.340
.345
.349
.352
66.5
66.2
64.7
64.7
64.0
63.7
.360
.370
.303
.399
.404
83.5
83.1
a3.9
83.0
82.5
.376
.3a4
.395
.407
.411
66.3
65.9
65.4
65.7
65.3
.410
.417
.432
.446
.461
.466
83.1
E3.1
83.6
83.1
04.1
83.8
.42a
.434
.446
.457
.470
.474
66.5
66.0
66.5
66.2
.06C+0 or M.
Ufw
2-48
3-56
.112-40or m. 4-40
.U-48 or !b. 4-48
ox
LaF
.16+32 or NO. 6-32
.164-36or WA 8-36
UNF
.190-24or lb 10-24
.290-32or 243.lC-32
w
Lx
OK
.216-24or lb. 2.2-24
.21620 or m. 12-28
.216-32or M. 12-32
.250-20or 3/4-20
.250-22or 2/4-20
.250-32or L/4-32
.250-36or 3/4-36
mc
13m
2Cm
Cm
2m
UMT
ma
ox
16U4
w
32m
.50C-22or 3/3-12
.500-13or 2/2-13
.500-16or W-16
.50C+20or 3/*Z
.500-38or 3/3-2E
.50C+32or U2-32
See fmt730tesat e
of table.
34
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H
●
Htntlmml
limits for diftesent;
*
AtlYM 0.330 &“
M0m3 0.670 thru 1.53!
!4dna3 s!= in *
adt.hreadsperird
mxifm
UlnImm
B
9
10
2n
●
o.6m
of ~t
mximxa
in
32
1
0.&65
0.0500
0.;79
in
0.0514
0.0479
In
0.0514
.060%0as m. M30
.0563
.0560
.0599
.062.3
.0560
.696
.062.6
.0624
.0565
.0602
.0622
.0635
.m~~
m. I-64
.07>72 or lb. 1-72
.0667
.0691
.0705
.0724
.0626
.0707
.0724
.0740
.0699
.0720
.0737
.0753
.086-56
OK b. 2-56
.086+4or b. ‘N4
..0764
.0797
.0604
.0831
.0785
.0014
.0225
.0848
.0205
.0831
.0045
.0865
.03+48 or b. 3-48
.099-56or lb. ?-%
.0849
.0894
.oa49
.0931
.0871
.0912
.0916
.0949
.0894
.0931
.0929
.0%8
.2M-40 or m. 4-40
.3X4-48or m. 4-48
.0479
.1004
.1020
.Lou
.1000
.1023
.1043
.1060
.1023
.1042
.1062
.lm9
.125-40or m.
.32s-44or m.
HO
5-44
.104
.332
.109
.235
.106
.223
.2.22
.U7
.lm
.3.25
.114
.129
.138-32or m.
.238-40or m.
6-32
6-40
.230
.134
.135
.228
.132
.136
.137
.140
.2.34
.228
.139
.142
.164-32or lb. +32
.164-36ox b. 6-36
.145
.156
.250
.160
.147
.E8
.253
.162
.150
.160
.2s6
.164
.390-24Or b.
.39C-32or h.
.m
.u7
.M2
.176
.182
.3B6
.m
.179
.264
.178
.184
.288
.176
.221
.2.66
.181
.266
.25’0
12-24
.216-24or h
.236-20.OZ m. P26
.236-32or m. 12-32
.296
.22.3
.216
.2’M
.202
.216
.220
.223
.B9
.233
:%
.204 .(
.222
.222
.225
.202
.216
.220
.222
.207
.220
.224
.226
.350-m or 3/4-20
.230-200s 2/4-20
.25*32 or 3/4-32
.250-26or 2/4-36
.252
.254.
.167
.274
.279
.202
.259
.264
.272
.276
.262
.286
.256
.261
.27o
.276
.220
.203
.262
.267
.275
.260
.284
.287
.259
.264
.272
.278
.2a2
.205
.265
.270
.277
.262
.266
.=9
3125-1Sor 5/36-32
3125-20or 5f16-2c
3125-24or 5W24
3125-26or 5/16-26
32Z5-32or 5/36-32
3125-36or V26-24
.307
.322
.330
.336
.342
.345
.314
.327
.335
.340
.345
.348
.323
.326
.332
.338
.343
.346
.318
.330
.337
.343
.347
.350
.314
.327
.335
.340
.345
.348
.323
.332
.340
.345
.349
.352
.375-16or 3/S16
.37>20 or 3/8-20
.37>24 Or 3/6-24
.375-20or 3/2-22
.37532 or 3/S32
.375-36or 3/S36
.360
.370
.383
.399
.404
.368
.377
.389
.403
.407
.364
.373
.386
.403
.405
.372
.320
.392
.405
.409
.360
.377
.389
.403
.407
.376
.384
.395
.407
.433
8375-140[ 7/3.6-14
1375-16or 7/36-16
wrf-m or 7/26-20
137s-22or 7/36-22
137>32 m 7/M-32
.410
.U7
.432
.446
.4Q
.466
.429
.425
.422
.452
.466
.470
.414
.421
.436
.449
.463
,468
.423
.430
.443
.454
.468
.412
.43!4
.425
.439
.452
.466
.470
.422
.434
.446
.457
.470
.474
50c-12or 2/2-12
.50C-13or 3/2-13
,500-16or 3/>16
.Soo-m or 3/2-20
.500-22or 3/2-28
.50C-32m 2/2-32
See
fcotnotesat end of table.
35
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!1
lb24
10-32
~STEH28/2B
‘B&E 11A.+=
kamx%x3ed
txzhzsize limits tefore threadiq for diffezent krqths of engiqemnt,
Unified u-d safe UNS thzea&, chsses D and 2S (see 30.11 IJ - untinkd
Nminalsize in inches
Fm5threads
per inch
Series
designatim
Fer03mY
of
lhread
3
2/
Uaxiirmn
4
sbrdard
●
Percent.Y
of
l?uead
6
in
.5625-12 or 9/26-32
.5625-16 or 9/26-16
.5625-18 or 9/36-18
.5625-20 or 9/16-20
.562524 or 9/16-24
.5625+20 or 9/16-28
.5625-32 or 9/16-32
2mN
3am
.412
.495
.502
.508
.517
.524
.529
83.6
83.1
83.8
e3.9
84.1 .
e3.o
82.5
.4mw
.509
.525
.520
.527
.532
.536
67.o
65.9
65.8
65.4
65.6
65.7
65.3
.625-3.8at 5/8-18
.625-20 or 5/8-20
.625-24 Or 5/8-24
.625-28 or 5/8-28
.6&32
or 5/8-32
w
2.3U?
16UN
l.uw
20026
m
2mN
33U4
.527
.535
.557
.565
.571
.580
.566
.591
83.0
83.1
83.0
83.1
83.1
83.1
84.1
83.8
.546
.553
.571
.578
.582
.590
.595
.599
66.9
66.5
66.5
65.1
66.2
64.7
64.7
64.0
.6875-12
or
.6875-16 or
.6875-18 or
.687+20 or
.687+24 Or
.687528 or
.6875-32 or
12UN
lam
m
20UN
K322F
285S
3mN
.597
.620
.627
.633
.642
.649
.654
83.6
e3.1
83.8
83.9
84.1
e3.o
82.5
.615
.634
.640
.645
.652
.657
.661
67.0
65.9
65.8
65.4
65.6
65.7
65.3
.75C-1001 3/4-10
.750-12 or 3/4-12
.750-16 or 3/4-16
.750-18 or 3/4-18
.750-20 or 3/4-20
.750-28 or 3/4-28
.750-32 m 3/4-32
m
127JN
w?
m
w
26UN
3mN
.642
.660
.682
.690
.6%
.713
.716
B3.1
83.1
83.8
83.1
e3.1
84.1
83.B
.663
.670
.6%
.703
.707
.7m
.724
67.0
66.5
66.5
65.1
66.2
64.7
M.o
3mN
12UN
us
..oNir
2m
3ZM
.722
.745
.752
.75a
.774
.779
83.6
e3.1
83.8
a3.9
83.0
e2.5
.740
.759
.765
.770
.7e2
.786 .,
67.o
65.9
Luc
12UN
w
Mm
m
m
261m
32m
.755
.785
.758
.807
.815
.821
.836
.841
e3.1
83.1
e3.o
93.8
83.1
e3.1
84.1
e3.8
.778
.803
.814
.ezl
.828
.832
.845
.849
67.2
66.5
65.7
66.5
65.1
66.?
fd.1
64.0
12L2+
lam
m
2mN
32UN
.847
.S70
.803
.e99
.?,]4
e3.6
e3.1
83.9
e3.o
82.5
.865
.884
.e95
.907
.911
67.0
65.9
.625-u or 5/8-11
.625-12or 5/8-12
.625-16or 5/8-16
.875-9 C: 7/8-9
.875-12or 7/8-12
.875-14 Or 7/0-14
.875-16 or 7/8-16
.P75-18 or 7/8-18
.875-20 or 7/B-20
.87S28 or 7/8-28
.875-32 os 7/8-32
.9375-12
or 15/16-12
.937516or 15/16-16
.937>20 or 15/16-20
.9375-28 or 15/16-28
.937532 or 15/16-32
*
fmtnotes at end
Inc
mm
w
cmc3-
ale .
36
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Check the source to verify that this is the current version before use.
65.8
65.4
65.7
65.3
65.4
65.7
65.3
●
‘
●
-s273-H28/2B
?S+?JZ
11.A.3-- &mmenkd
. .=
---
Reccmrer&d
ble
Ikzk size limits &r
Abw
-
different h
0.330 till 0.67D
sbdard
Ith of mgag.3Tent
AkNe o.6m till1.5D
tbina.1size fn inches
ard thre&2s per inch
Minilrm
14axflmm
Hir.imm
7
8
9
in
a
.502
.472
.495
.502
.508
.517
.524
.529
.
in
.4n
Ma%h.m
10
u
3.2
1
fn
in
in
.509
.514
.522
.53s
.532
.498
.506
.531
.520
.526
.530
.486
.505
.532
.517
.525
.530
.534
.4s2
.502
.509
.514
.522
.526
.532
.490
.509
.53.5
.520
.527
.532
.536
.5625-2.2
or 9/26-22
or 9/26-16
.5625-16
or 9/26-18
.5625-2B
.562E-2oor 9/1+20
.562524 or 9/M-24
or 9/!lG2B
.5625-26
.5625-32m 9/16-32
.527
.535
.557
.565
.571
.580
.5s6
.591
.536
.544
.564
.571
.5n
.5s5
.590
.595
.532
.539
.562
.568
.574
.582
.5s8
.593
.541
.54B
.56S
.574
.5$0
.587
.593
.597
.536
.544
.564
.571
.sn
.5B5
.590
.595
.546
.553
.571
.57B
.502
.590
.595
.599
.625-3.3or 5/B-31
or 5/6-12
.625-3.2
.625-16 or 5/S-16
.591
.620
.627
.633
.642
.649
.654
.606
.627.
.634
.639
.647
.653
.657
.6o2
.623
.630
.636
.645
.651
.655
.62.3
.630
.637
.642
.650
.655
.659
.606
.627
.634
.639
.647
.653
.657
.61.5
.634
.640
.645
.652
.657
.663
.642
.660
.682
.690
.696
.731
.116
.652
.6697
.689
.6%
.702
.716
.720
.647
.664
.686
.693
.699
.7D
.72s
.658
.673
.693
.699
.704
.72s
.722
.652
.669
.6B9
.696
.702
.716
.721
.663
.676
.696
.703
.707
.720
.724
.750-10or 3/4-10
.750-12m 3/4-12
.750-16or 3/4-16
or 3/4-18
.750-2.s
.750-20or 3/4-20
.750-2Sor 3/4-26
.750-32or 3/4-32
.722
.745
.752
.7’58
.774
.179
.731
.752
.759
.764
.778
.702
.727
.748
.756
.761
.n6
.780
.736
.755
.762
.767
.7s0
.7s4
.731
.752
.759
.764
.B125-12or 13/16-12
.6225-16
or 13/16-16
or 13/26-3.8
.52.25-2.6
.B3Z5-20or 13/26-20
.782
.746
.795
.765
.770
.782
.786
.s325-2s or 1016-2B
.B2Z5-32 or 13/16-32
.755
.785
.798
.807
.835
.821
.766
.794
.806
.814
.823
.827
.840
.845
.760
.789
.802
.ul
.810
.824
.838
.843
.772
.79B
.B1O
.83,s
.824
.B30
.843
.B47
.766
.794
.806
.B14
.B21
.827
.840
.845
.778
.B03
.B14
.821
.828
.832
.845
.849
.87+9
0.?7/8-9
.87>12 or i’/B-l2
.B75-14 or 7/B-14
.875-16 os 7/8-16
.875-18 or 7/B-18
.875-20 or 7/s-20
.875-28 or 7/8-28
.87~32 OS 7/8-32
.856
.852
.873
.BB6
.901
.905
.861
.BSO
.S92
.905
.909
.856
.877
.BB9
.903
.907
.865
.884
.095
.907
.911
.937512m 3.5/16-12
or 3.5/16-16
.9375-16
.9375-200235)26-20
.9375-26
m 2s/26-20
.937532or 25/16-32
.836
.842
.847
.870
.883
.899
.904
Ses
size lfmfts bebre thrediq
for different lengths of erqqanent,
m
IRS threaas, d855es D and 2S (see 30.1)1/ - mxmina
. Unified ad
.=.
.8n
.889
.903
.907
fcotiotesat end of table.
.778
’37
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Check the source to verify that this is the current version before use.
.625-18OK 5/S-lB
.625-20or 5/s-20
.625-24or 5/0-24
.625-2B or 5/0-23
.625-32015/S-32
““
i?EESTD-H28/2H
19@u311.A.3- ~
.,
. ..-.
-.
._. _>.
bk SiZ limitsbb:e
3222ifie3a793
-3x9th2’ea,
threading br different lerqths of qpt,
~
ls30Ya2E (see30.l)y-mtti
..
dkza
o
3
P&ma
W.run&
&
1
3
4
5
1.000-8
1.WC-U
1.ML=14
1.-16
1.*23
1.-29
1.000-26
1.WO-22
.86S
.92a
.922
.932
.940
.966
.961
.966
83.1
83.1
63.0
83.0
83.1
83.1
84.1
83.8
.890
.93s
.92a
.946
.952
.957
.970
.974
.927
.972
.985
.995
1.002
1.009
1.024
03.4
.83.6
83.5
83.1
83.8
83.9
83.0
.952
.930
1.OCII
1.009
1.023
1.020
1.032
0.970
.990
1.023
1.057
1.065
1.071
1.096
83.s
83.1
83.1
82.9
83.1
83.1
84.1
0.99B
1.035
1.052
1.071
1.078
1.C82
1.095
68.4
67.7
66.5
2a31
1.0s2
1.097
3.220
1.127
1.233
1.149
B3.4
83.6
83.1
83.8
83.9
83.0
1.077 ‘
l.lls
1.124
1.140
1.145
l.m
68.1
67.0
65.9
65.8
65.4
65.7
w
ml
m
LR
1.160
if%
am
1.182
1.190
1.1%
1.232
83.5
83.1
83.1
83.6
83.1
83.1
84.1
1.222
1.140
1.170
1.1%
1.203
1.2m
1.220
60.4’
67.7
66.5
66.s
65.1
66.2.
44.1
1.33256
1.3125-12
1.317S-16
!..
3U5-18
1.3125-20
1.3223-in
m
lam
161.31
w
2cul
Zmm
1.177
1.222
1.245
1.252
1.269
1.114
83.4
83.6
83.1
83.8
03.9
03.0
1.202
1.240
1.259
1.265
1.270
1.282
68.1
67.0
65.9
65.0
65.4
65.7
1.31.375-6
1.37+13
1.37516
1.37+18
1.375a
1.375-28
m
m
ma
1.195
1.240
1.283
1.3L77
1.32.5
1.37.2
1.334
82.1
83.1
83.1
83.0
83.1
83.1
84.1
3.223
1.265
1.303
1.32)
1.328
1.333
1.343
69.3
67.7
66.5
66.5
65.1
66.2
64.7
1.4315-6
L.4375-8
1.h375-22
1.437+16
1.437>19
1.437+20
1.4375-20
Q.N
m+
1224
E3.4
83.4
83.6
83.1
83.8
83.9
83.0
1.Z8
1.327
1.365
1.384
1.390
1.395
1.407
69.1
68.1
67.0
65.9
65.0
65.4
65.7
83.1
83.3
83.1
a3.a
83.1
83.1
64.1
1.3S0
1.390
1.4’23
1.466
1.453
1.457
1.470
69.3
67.7
64.5
66.5
65.1
66.2
44.1
m
lZM
14221
w
mm
2mnl
1.12S-7
1.2258
1.125-22
1.223-16
1.125-2s
1.123-20
l.mia
1.26758
1.ls7512
1.387S-16
1.2237+
2.0
1.1675-20
1.2B7>i$
1.5U-6
l.sowe
1.300-12
1.500-16
1.500-10
1.500-30
1.500-28
See
s-d
w
lM
E
mol
s
2M34
2mm
=
2m14
lmc
6m
13w
Ll&$
201J4
26W
fczhotes at end of tihle.
38
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Check the source to verify that this is the current version before use.
.%;
66.3
65.9
65.8
65.4
65.7
6?:
66.2
64.7-
●
F3%D-STD-H28/2B
-
●
11.A.3-
Rxxxmended ble size lSmits kfore threadfng for dif Eerent leqtb
of erq6g@m?nt, stamkxd
Unified ti sme UKi threti, classes 3B and = (.93.3
30.1) 3J - .xzztimzd
;. ‘~
m
ad inchdiq (1.3D
14inlmn
●
b2s aim lkks
fordiftermt kq?im of ~t
Mvvc 0.3m thru0.67D
P&W
0.6792tuul.m
~b
Kaxim3a
6baimm
8
M
u
12
.804
1
.865
..910
.923
.932
.940
.946
.962
.944
.877
.939
.932
.939
.946
.9S2
.9+6
.9m
.871
.914
.927
.936
.943
.9i9
.%3
.94a
.923
.934
.943
.949
.954
.96E
.972
.8n
.929
.931
.939
.946
.9S2
.%6
.970
.890
.929
.92a
.944
.9s3
.957
.9m
.974
1.000-s
1.000-12
1.00C-14
1.000-26
L.mu
1.O*2O
l.oocl-z
1.029-32
.927
.972
.903
.993
1.002
l.om
1.024
.940
.901
.993
1.002
1.009
1.014
1.02a
.926
.9n
.909
.998
1.W6
1.023
1.026
.946
.9S6
.?97
1.m3
1.032
1.017
1.OXI
.940
.981
.993
1.M2
1.004
1.014
1.028
.962
.990
1.003
1.009
1.023
1.020
1.032
1.0625-4
1.0625-32
1.06zr14
1.0625-16
1.06S36
1.oa5-iQ
1.0625-26
0.970
.990
1.03s
1.037
1.065
1.072
1.066
0.984
1.002
1.044
1.CU
1.071
1.077
L090
0.977
1:%
1.041
1.066
1.074
1.0s8
0.991
1.00B
1.048
1.066
1.074
l.ozn
1.093
0.964
1.002
1.044
1.064
1.071
1.077
1.090
0.996
1.035
1.053
1.071
1.076
1.022
1.09s
1.12.5+9
1.032
1.097
1.120
1.227
1.331
1.149
1.26
1.106
1.227
1.U4
1.239
1.M3
1.0$9
1.102
1.223
1.230
1.136
1.231
1.071
1.077
tE
1.137
1.142
1.355
1.065
1.206
1.127
1.134
1.139
1.233
::s
1.140
1.145
1.357
1.095
1.2.25
1.340
1,,+22
1.290
1.196
1.231
1.109
1.127
1.169
1.109
1.296
1.202
1.22.6
1.302
1.ul
1.164
L 266
1.293
1.199
1.223
1.116
1.334
1.173
1.393
1.199
2.204
1.220
1.109
1.127
1.169
1.189
1.296
1.m2
1.216
1.323
1.140
1.1-68
1.396
1.203
1.207
1.2m
1.177
1.222
1.245
J.252
1.258
1.274
1.199
1.233
1.252
1.259
1.264
1.275
1.184
1.227
1.24S
1.236
1.261
1.276
1.L96
1.2%
L235
1.362
1.267
1.200
1.290
1.231
1.252
1.239
1.264
1.278
1.m2
1.240
1.259
1.265
1.270
1.2E2
1.195
1.240
l.im
1.307
1.335
1.323
1.336
1.230
1.2s2
1.2W
1.314
1.332
1.327
1.340
1.m2
1.246
1.’209
L323
1.330
1.324
1.338
1.229
1.230
1.29s
1.326
1.324
1.33S
1.343
1.220
1.252
1.294
1.314
1.321
1.327
1.340
1.225
1.265
1.303
1.321
1.3.29
1.332
1.365
1.375-4
1.37S-8
1.37s-12
1.275-36
1.375-38
1.27s-m
1.27S-2E
1.257
1.302
1,347
1.370
1.377
1.303
1.399
1.272
1.32s
1.356
1.377
1.384
1.389
1.403
1.265
1.3oa
1.352
1.373
1.260
1.386
1.401
1.-280
1.321
1.361
l.zao
1.387
1.392
L.405
1.272
1.323
1.356
1.377
1.384
1.389
1.403
1.288
1.327
1.365
1.384
1.390
1.395
1.407
1.4275-6
1.4375-6
1.4375-12
1.4375-16
1.4s73-28
1.4375-2U
1.4m528
1.3ZI
1.365
1.410
1.432
1.440
1.446
1.461
1.335
1.377
1.429
1.439
1.446
1.452
1.666
1.327
1.371
1.414
1.426
1.443
1.449
1.463
1.343
1.3S4
1.422
1.443
1.449
1.456
1.466
1.335
1.377
1.429
1.439
1.446
1.452
1.466
1.330
1.390
1.420
1.446
1.4s3
1.457
1.470
1.50C-6
1.500-8
1.300-12
1.500-16
1.500-lB
1.5oo-m
1.500-26
Seef
notes
end
of able.
39
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Check the source to verify that this is the current version before use.
1.250-7
1.250-6
1.250-12
1.25*16
1.2s2-20
1.2s0-20
1.25C-2E
-
IIA.3.-~
~.
tie sizeliaits
bsfnrethrediqh different
Jxqthsof~:,
6uIlew4hreadS,
c38sses 231am53s
(see30.1)
lJ-amtinw2
m
Mm?
zefnfnctrs
al’dthreadsperincb
Nmina2iai
diam?teto]
WIes
designatim
1
2
3
4
M
*
s
Mif+edald
,terral tb
s
2/
I%m2el#
Haxim.m
of
‘nueFd
5
6
fn
1.5625-6
1.5625-8
1.5625-22
1.5625-16
1.5625-3S
1.5625-20
m?
m
lzw
m2t4
m
1.382
1.427
1.472
1.495
1.s02
1.s08
83.4
83.4
83.6
83.1
83.s
S3.9
“1.423
1.452
1.490
1.509
1.52s
1.520
69.1
66.1
67.0
65.9
65.8
65.4
1.625-6
1.625-8
1.625-32
1.625-16
1.625-M
1.62S-20
SJN
m
1224
Mm
mm
2om4
1.445
1.490
1..s35
1.557
1.565
1.571
83.1
83.1
83.1
83.8
83.1
63.1
1.47s
1.52.s
1.553
1.571
1.578
1.5S2
69.3
67.7
66.5
66.5
65.1
66.2
1.6875-6
1.687>8
1.6s75-12
1.6S75-16
1.6s75-3s
1.6675-20
mN
1.507
1.552
1.s97
1.620”
1.627
1.633
83.4
S3.4
83.6
83.1
83.8
S3.9
1.53s
69.1
1.534
1.570
1.633
1.660
1.682
1.696
83.1
liutl
1s2!4
20UN
1.5n
1.635
1.634
1.640
1.64s
67:;
65.9
65.8
65.4
E::
83.1
83.8
83.1
1.56s
1.600
1.640
1.678
1.696
1.707
70.1
69.3
67.7
66.5
66.5
66.2
83.4
83.4
83.6
83.1
83.9
1.663
1.702
1.740
1.759
1.7m
69.1
6s.1
67.0
65.9
65.4
69.3
67.7
66.5
66.5
66.2
69.1
68.1
67.0
65.9
65.4
1.750-5
1.75f+6
1.750-8
1.750-12
1.75C-16
1.750-20
m
m
SLm
1.62.25-6
1.U25-8
l:ux-lz
1.8125-16
1.822s-20
64E4
m
mm
2om
1.632
1.677
1.722
1.745
1.759
1.87S-6
1.8758
1.87512
1.87516
1.875-20
tm4
m
Dm
la
20UN
1.695
1.740
1.785
1.807
l.szl
S3.1
83.1
w
83.1
1.72s
1.765
1.s03
1.821
1.832
1.9375-6
1.9375-8
1.9373-U
1.937516
1.9375-20
6m4
WN
MN
161n4
20UN
1.757
l.aoz
1.847
1.870
1.883
83.4
S3.4
83.6
83.1
83.9
1.788
1.827
1.865
1.884
1.895
2.000-4.5
2.000-6
2.000-8
2.000-12
2.000-16
2.OW-20
m
60N
8ot4
1.759
Lam
1.865
1.910
1.932
1.946
83.5
83.1
83.1
S3.1
83.8
83.1.
1.795
1.850
1.BSO
1.92s
1.946
1.9s7
lam
mn4
Mm
H
fmtnotes at end of tible.
40
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-
●
,
I
3’Ec-s213-E28/213
msl.z 11.A.3- ~
----
P ...s
Imle size limits &tire threading for different leqths of eqeqenent,
Lh-llfied-LW threads, c2a59e9 2s and m (see 30.1) y - atillu33
f bok
st.addrd
eim Mmitsztirdifferentlength of engagent
1
2b &d incluihg o.33n
Atove 0.330 thru 0.67D
AtUW 0.67D thnl1.5D
IF
Nminel size in inches
Flt-f3thmadsprincb
14inimun
in
in
2.3
22
in
.fn
1
1.382
1.427
1.472
1.49s
1.s02
1.s09
1.397
1.440
L 481
1.s02
1.509
1.s14
1.390
1.434
1. 4n
1.498
1. S06
1.531
1.40s
1.446
1.486
1.s05
1.53.2
1.517
1.397
1.440
L 401
1.502
1.s09
1.514
1.423
1.452
1.490
1.509
1.525
1.520
1. S625-8
1. S625-22
1.s625-16
1. S625-18
1.562S-20
1.445
1.490
1.535
l.sn
1.565
1.571
1.460
1.502
1.544
1.564
1.571
1.577
1. 4s2
1.4%
1.539
1.s61
l.sa
1.574
1.460
1.508
1.S48
1.563
1.574
1.ss0
1.460
1.s02
1.s44
1.s64
1.571
1.577
1.475
1.525
1.553
1.571
1.578
l.saz
1.625-6
1.625-B
1.625-12
1.62+16
1.62S-18
1.62S-20
1.507
1.S52
1.597
1.620
1.627
1.633
1.522
1.S65
1.606
1.627
1.634
1.639
3.535
1.558
L 602
1.623
1.630
1.636
1.530
1.571
1.631
1.630
1.637
1.642
1;522
1.56S
1.606
1.6?)
1.634
1.639
1.s38
I.sn
1.625
1.634
1.640
1.645
1.687Fr6
1.687S-8
1.687512
1.6875-16
1.6875-18
1.607s-20
1.534
1.570
1.6U
1.660
1.602
1.696
1.S50
1.ss5
1.627
1.669
1.6s9
1.702
1.s42
~.sn
1.621
1.664
1.686
1.699
1.S59
1.s93
.1.634
1.673
1.693
1.704
1.5s0
1.5s5
1.627
1.669
1.689
1.702
::%
1.640
1.678
1.696
1.707
1.750-5
1.7s&6
1.750-8
Z.750-12
1.750-16
1.750-20
1.632
1.677
1.722
1.745
1.758
1.647
1.690
1.731
1.752
1.764
1.640
1.684
1.727
1.748
1.761
1.655
1.696
1.736
1.755
1.767
1.647
1.690
1.731
1.752
1.764
1.663
1.702
1.740
1.759
1.770
1.812s-6
1.RU5-S
1.8125-22
1.0U5-16
1.8125-20
1.69S
1.740
I.78s
1.807
l.ml
1.710
1.752
1.794
1.814
1.827
1.702
1.746
1.789
1.822
1.824
1.72E
1.750
1.79B
1.818
1.830
1.710
L752
1.794
“1.814
1.827
1.72s
1.765
1.803
1.WU
1.832
1.87M
1.875-8
1.875-12
1.87S-16
1.87520
1.757
1.802
1.847
1.870
1.883
1.n2
1.s35
1.E56
1.877
1.8s9
L 765
l.wa
1.8s2
1.873
1.s.86
1.780
1.821
1.861
1.B80
1.892
1.772
1.835
1.856
1.8n
1.8s9
1.788
1.827
1.865
1.884
1.s95
1.9375-6
1.9375-8
1.9375-12
1.937516
1.937>20
1.759
1.S2U
1.86s
1.910
1.932
1.946
1.777
1.835
1.877
1.919
1.939
1.952
1.768
1.827
1.871
1.914
1.936
1.949
1.786
1.043
1.B84
1.923
1.943
1.954
1.777
1.835
1.877
1.929
1.939
1.952
1.795
1.8s0
1.890
1.928
1.946
1.9s7
2.00C-4.5
2.000-6
2.000-8
2.00C+12
2.000-16
2.000-20
See
I
faJtnotesat em3 of table.
41
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1.S625-6
Ew-s’Iwz28/a
●
.=,
2%BtZ 11.i3
;-.~
lmle size MmLts bebce thswding for different lerqths of eq&&nt,
Unified and mre W
thretds, Cf.fl
ad m (sse 30.1) ~ . -&*
~simininches
?lrdthre.adsperirch
sxies
des igmatim
k
Mi
Ikmentv
Mi.nimm
=lF
2
3
&
4
in
2.062!+16
5
6
in
1.995
83.1
2.0U3
65.9
83.1
16U4
XKR4
1.945
1.990
2.035
2.057
2.071
83.1
83.1
83.8
83.1
1.975
2.02s
2.o53
2.071
2.082
69.3
67.7
66.5
66.5
66.2
2.3E75-16
lx
2.la3
83.1
2.334
65.9
2.250-4.s
2.250-6
w
Sam
2.009
83.5
83.1
2.045
2.100
71.0
69.3
2.5C4)-4
2.%
3.000-4
3.250-4
Um
2.229
2.479
2.729
2.979
2.267
2.517
2.767
3.017
71.7
71.7
71.7
71.7
2.125+
2.U+6
2.225-12
2.3.25-16
2.225-20
See botmtes
ml
mm
WC
m
2.om
:::
83.4
83.4
at E-X3of table.
I
I
I
I
I
42
L
star&JKd
Source: http://assist.dla.mil -- Downloaded: 2024-05-14T13:44Z
Check the source to verify that this is the current version before use.
●
FE23-STD-I?28/2B
.-.
~
bale siza 3.fmiteti
ard fm2h251ng 0.330 IIAbve
m
. ––—
different L
0.3m thfu 0.67D
!kmfnalaizef.nti
Ludthretdspximll
6uldms0 M82icd0nfniam
~
Nfnf2mn
7
8
9
10
2-3
23
in
in
fn
in
in
h
2.002
1.998
2.005
2.002
2.009
2.0625-16
1.945.
1.990
2.035
2.037
2.072
1.960
2.002
2.044
2.064
2.077
1.952
1.996
.2.039
2.061
2.074
1.96E
2.008
2.048
2.060
2.060
1.%0
2.002
2.044
2.064
2.077
1.975
2.025
2.053
2.071
Z.C&?
2.3.25-4
2.=8
2.125-12
2.323-16’
2.12?+
2.320
2.227
2.322
2.230
2.127
2.334
2.3S7%16
2.009
2.070
2.027
2.065
2.03.8
2.077
2.036
2.093
2.027
2.085
2.04s
2.100
2.250-4.s
2.250-6
2.22s
2.479
2.?39
2.979
2.240
2.498
2.748
2.998
2.239.
2.4a9
2.739
2.989
2.254 ‘2.508
2.756
3.008
2.240
2.498
2.746
2.998
2.20
2.517
2.767
3.017
2.300-4
2.750-4
3.oco-4
3.=0-4
1.995
●
Mlxilmm
%
1
~~yg
Liu3mgth90f
be.limits.e qud
m tb Anc.r dimcu~
tdermxs
=Jw==t-~
gredter than 0.33nin Sims 0.25 in.
Ibever, *
minikam v83ues -r lengths of aqagewmt
and hrgez &e &!smd
w that th! difference &been
lfmfm Is _
less b
0.0040 h.
ror dimce-piti &inaticzm
ot.br tbm tlcee given in this mk.2e, am 30.2.
Zble nize limits &a
dun
in this @da
dimcet.ec-piti ccmbfnatims which * -t ~
prcdded them is a diareter~imh ux&dnatim
fn this W
fn ths tabki
my
k
*--
M
M
Of
(1) b-itht6=cuImpimbm3
(2) with~ dtik
thatis lessty m fntegm2 tmnmt &m
vabm
aze &sized,
this pq2192. )
0211S: Values In *
“ tfm fm which ka3e sizs
carhna
sizes 2ess ttmn 0.25 in. c9m0t be used far
tb dfmrebr+ti
table fur mninn3
E2P2KlW lb cbtain *
values for *
4.0*S2E
or = thread, ad
‘17)esa
value.quuld thm ~:
Uueadslxamh t!mtahle.
3.890. m
PCrmlas
of thread Wu.2 Zemfn Imchmlpea.
2J B.mA cm .Ue2.
.
lJ0asedonak@hofwwtqa3
randed off in tke prhirq
.lum.
2.000 b n2WS
&r *
2.000-5N
3.865, 3.877, 3.871, 3.B84, 3.877,
100 perumt of threzd - 0.791 [see 30.2.3).
tntlt?mmdrtal ditureter.
43
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Check the source to verify that this is the current version before use.
FED-ST13-H28/29
7mmE 11.?+.4
- ~EX7
Imle sizelimitsbeforethreadiq h differentkqtb
Onifiedd s=e W tbreds, *
3B [see30.1)~
of mgagment, st.ard
9
?linor
diambx of inte~
~e
I
*r ies
Iesignatim
“a
FercentY
of
Thread
Y
taxim.m
3
4
5
6
in
0.0465
83.1
0:514
53.0
I
Per02ntY
of
‘1’nread
I
1
I
.060-8001lb. 0-80
trw
.073-64 or N2. 1-64
Lrc
.0561
.0580
83.3
83.1
.0623
.0635
OK
.0667
.0691
S3.2
83.3
.0737
.0733
53.0
52.7
m?
.0764
.0797
83.5
83.2
.0845
.0865
53.6
53.9
UK
Um
.0849
.0894
83.4
83.5
.0939
.0968
55.7
56.2
.0979
.1004
83.4
83.3
.1062
.1079
57.9
57.9
.073-72or tb. 1-72
.086-56or No. 2-56
.086-64or No. 2-64
.099-48or M. 348
.099-56or lb. 3-56
.122-40or b
m
IRK
or M.
4-40
4-48
.125-40or m.
.12544 or W.
5-40
m
544
02-F
.3X+48
.13S-32or b. 6-32
.138-40or No. 6-40
w
.1040
.Ulo
83.8
83.1
.2240
.12E6
59.1
59.7
.164-32or M. %32
Lw
UNF
.3300
.3.340
83.8
83.1
.1389
.1416
62.8
62.1
.2.90-24
or No. 10-24
.290-32or N& 10-32
w
.1450
.3S60
83.1
83.8
.3.55s
.1643
63.7
63.8
.216-24or M. 1%24
.216-28 or NU. 12-2a
.216-32 or M. 12-32
W
Low
.1710
.1770
.1820
83.1
84.1
83.8
.1807
.M57
.1895
65.2
65.3
65.3
.25C-20
.250-28
.250-32
.25C-36
UK
InfF
OtEf
.1960
.2110
.2160
.2200
03.1
84.1
83.8
83.1
.2190
.7.229
.2258
66.7
66.8
66.8
m.1
.3125-M
.3125-20
.312524
.3125-28
.312>32
.3125-36
o-m
2UIN
2671N
m
m
.2520
.2580
.2670
.2740
.2790
.2820
83.8
83.9
84.1
83.0
82.5
84.5
.2630
.26E0
.2754
.28o7
.2847
.2877
68.5
66.7
.375-16
.37>20
.375-24
.375-28
.375-32
.375-36
‘K
20UN
UNF
2euN
IilJm
m
.3070
.3210
.3300
.3360
.3410
.3450
.93.
e
83.1
83.1
84.1
83.8
83.1
.3182
.3297
.3372
.3426
.3469
.3501
70.0
69.7
69.0
69.8
69.2
69.0
.4375-14
.437>16
.4375-20
m
16UN
.431!+28
.4373-32
m
327RJ
,3600
.3700
.3830
.3990
.4040
83,5
83.1
83.9
83.0
82.5
.3717
.3800
.3916
.4051
.4094
70.9
70.8
70.7
69.8
69.2
.164-36 or W.
*
fwb-des
8-36
m
w
at d
of tah3e.
44
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Check the source to verify that this is the current version before use.
●
68.6
::;
68.5
,
,.
“o
FED-S2D-H28/2B
m15LE 11.A.4- ~ed
tde size limi= tefore threading for different lengths of eqag-t,
unified ard 6are IN
.-.
--
Wmmm5ed
ck
3B (see 30.1) y
W
0.33Dth?uo.6m
..
Abve 0.67Dthcu1.5D
W.%ium
sbdard
- amtinued
bsle size limits for different length$ of aqagenent
m a-d fnchdij-lg
13.33D
~ti
*e&,
txnfm.1size in incks
ardt&ead6periJlctl
Mxiumn
8
~
9
10
u
~
~
~
0.g65
0.0500
0.0479
0.0514
0.0479
0.214
.062-s0or lb.
..0561
.0580
.0599
.062.3
.0580
.0596
.0618
.0629
.0505
.0602
.0623
.0635
.073-64or tb. 1-64
.073-72or tb. 1-72
.0667
.0691
.0705
.0724
.0686
.0707
.0724
.0740
.0699
.0720
.0737
.0753
.096-56or W.. 2-56
.086-64or w. 2-64
.0764
.0797
.0804
.0831
.0785
.0814
.0825
.0848
.0805
.0831
.0845
.0865
.099-48 or &a. 3-48
.099-56 or W. >56
.0849
.0894
.0894
.0931
.0871
.093.2
.0916
.0949
.0894
.0931
.0939
.0968
.2X+40 or M. 4-40
.3.32-4.9
or f&. 4-48
.0979
.1004
.lom
.1041
.1000
.1023
.1o41
.1060
.1022
.1042
.1062
.1079
.125+0 or W.
.225-44 or m.
.1040
.Ulo
.1091
.3.348
.1066
.2128
.3M5
.3.267
.1091
.1147
.1140
.2186
.13S32 or b. 6-32
.238-40 or No. 640
.2300
.1340
.3.345
.1371
.1324
.1359
.1367
.1397
.1346
.1378
.1389
.1416
.164-32 or N% S32
.164-36 or tb. 6-36
.1450
.2560
.3.502
.1601
.1475
.3.582
.1520
.1623
.1502
.1602
.2555
.1641
.39*24 or No. 10-24
.190-32 or W. 10-32
.1710
.1770
.1820
.1756
.183.5
.185a
.1733
.1794
.1043
.1782
.1836
.1877
.1758
.181S
.1859
.1807
.1857
.1095
.2M-24 or tb. 1>24
.216-28 Oc W.. 12-28
.216-32 or W. 12-32
.1960
.2110
.2160
.2200
.2013
.2352
.2196
.2223
.1986
.2131
.2172
.2203
.2040
.2171
.2212
.2243
.2013
.2250
.2189
.223.9
.2067
.2190
.2229
.225a
.250-20
.250-28
.25*32
.250-36
.2520
.2500
.2670
.2740
.2790
.2E20
.2577
.2632
.2714
.277’2
.2817
.2E50
.2551
.2600
.2694
.2749
.2792
.2823
.2604
.2656
.2734
.2789
.2832
.2863
.2577
.2632
.2714
.2767
.2807
.2837
.2630
.2680
.2754
.2807
.2047
.2877
.33.2518
.3125-20
.3070
.3210
.3300
.3360
.3410
.3450
.3127
.3253
.3336
.3395
.3441
.3475
.3101
.3231
.3314
.3370
.3415
.3450
.3155
.3275
.3354
.3410
.3455
.3490
.3128
.329
.3332
.33S6
.3429
.3461
.3182
.3297
.3372
.3426
.3469
.3501
.375-16
.375-20
.375-24
.375-28
.375-32
.315-36
.3600
.3700
.3830
.3990
.4040
.3660
.3749
.3875
.40m
.4066
.3630
.3723
.3855
.3995
.4040
.3688
.3774
.3896
.4035
.4080
.3659
.3749
.3B75
.403.I
.4054
.3717
.3800
.3916
.4051
.4094
.4375-14
.4375-16
.4375-20
.4375-28
.4375-32
7
See
foomotes
at eti
32
of table.
45
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Check the source to verify that this is the current version before use.
1
0-80
5-40
-4
.33.25-24
.312528
.3125-32
.3125-36
FE&STD-H28/2B
‘3m3L211.A.4 - Wc$mmcm2& hzle size limits before fhrezdirqfor differentlqtba
Onified ad s.ne 11+3ttuewfs, ck15 ~ (662 30.1)~ . ~~~
.- -.
.:
of
starctard
eqqemsnt,
..
Ninor diaseterof internrd rim
NOniml size in incks
ad threads pm M
2
1
—7Percena
*5 ies
desiccation
3
of
17xecd
naximm
4
5
~
.500-32
.500-13
.500-16
.500-20
.500-26
.500-32
0?s
w
lam
3aN
.5625-32
.5625-16
.5625-2B
.5625-20
.562524
.5625-28
.S62532
.625-11
.625-12
.625-16
.625-36
.625-20
.625-24
.625-28
.62532
Lx
12LX
lam
32LN
.6s75-12
.6K7516
.6875-18
.6075m
.6675-24
.6675
-28
.4875-32
lm
.750-10
.750-12
.750-16
.750-18
.750-20
.750-28
.750-32
m
120N
U6P
IRS
m
.8U5-12
.s125-16
.8125-18
.w+rn
.8125-28
.8125-32
.875-9
.875-12
.875-14
.87+16
.875-18
.875-20
.875-28
.875-32
.9375-12
.9375-16
.9375m
.93-H-2a
.9375-32
See fa.tnotis at d
Zm
331m
16xm
m
w
2m
3am
ioc
U&N
w
16m
13f65
2WN
3212.’
lam
2olN
32m
of table.
6
in
.4100
.4170
.4620
.4660
83.1
83.1
83.B
83.1
84.1
03.8
.4223
.4264
.4434
.4537
.4676
.4719
71.8
71.1
71.6
71.3
69.0
69.2
.4720
.49s0
.5020
.5080
.5170
.5240
.5290
83.6
83.1
83.8
83.9
64.1
83.0
82.5
.4843
.5040
.5106
.5162
.5244
.5301
.5344
72.2
72.1
71.9
71.3
70.4
69.8
69.2
.5270
.5350
.5570
.5650
.5710
.5BO0
.586o
.5910
03.0
83.1
83.8
B3.I
83.1
B3.1
B4.1
B3.8
.5391
.5463
.5662
.5730
.5787
.5269
.5926
.5969
72.7
72.7
72.4
72.1
71.3
70.4
69.8
49.2
.5970
.6200
.627o
.6330
.6422
.6490
.6540
83.6
B3.1
83.0
83.9
24.1
83.0
82.5
.6085
.62S4
.6355
.6412
.6494
.655J .
.6594
13.0
12.8
72.1
71.3
70.4
69.B
69.2
.64m
.6600
.6Bm
.6900
.6960
.73.30
.7160
B3.1
E3.1
83a
83.1
83.1
54.1
83.6
.6545
.6707
.6900
.69S0
.7037
.7176
.7229
13.5
73.3
72.9
72.1
71.3
69.8
69.2
.72m
.7430
.75m
.75m
.7740
.7790
83.6
83.1
83.8
B3.9
83.0
82.5
.7329
.7533
.7605
.7662
.7801
.7844
73.5
72.9
72.1
71.3
69.8
69.2
.7550
.7850
.7980
.8070
.0150
.8210
.836o
.8410
E3.1
B3.1
83.0
83.8
63.1
83.1
04.1
83.8
.7681
.7952
.8068
.815B
.8230
.8207
.8426
.8469
74.1
73.7
73.5
72.9
72.1
71.3
69.0
69.2
.8470
.8700
.8630
.8990
.9040
83.6
B3.1
B3.9
83.0
02.5
.8575
.8783
.8912
.9051
.9094
73.9
72.9
71.3
69.8
69.2
.43m
.4460
46
Source: http://assist.dla.mil -- Downloaded: 2024-05-14T13:44Z
Check the source to verify that this is the current version before use.
,
2?IB2.E
11.A.4- ~
lde size limits tefnre thseadiq fnr different Zerqths of e!qqe7rent, stzdard
Uoified ad sme M
*e*,
*
3B (=
30.11 ~ - afi~
----
._n=+-@=o
mamlti
Im2e size limits 20? different h
*
0.33D
mximm
8
0
a
Ak&
h
of engagmt
II
0.33Dthru0.670
‘Junimm
9[ ~
]
9
10
~
~
~
.4223
.4284
.4419
.4537
.4676
.4724
.500-2E
.500-32
in
511
.4100
.42m
.43m
.U29
.41%
.4192
.4234
.4460
.4610
.4660
.4161
.4225
.4371
.4498
.4645
.4691
.4347
.4477
.4620
.4665
.4395
.4517
.4660
.4705
.4160
.4226
.4371
.4497
.4636
.4679
.47m
.4950
.som
.5080
.5170
.5240
.5290
.4783
.4994
.5065
.5123
.5209
.5270
.5316
.4753
.49n
.5043
.5102
.5186
.5245
.5290
.4813
.5017
.5066
.5142
.5226
.5285
.5330
.4703
.4994
.W65
.5122
.5204
.5261
.5304
.4043
.5040
.5106
.5162
.5244
.5301
.5344
. 5625-3.i
.5625-16
.5625-18
.5625-2o
.562>24
.5625-24
.5625-32
.5270
.5350
.5570
.5650
.5710
.5800
.5660
.5910
.5328
.5406
.5617
.569o
.5748
.5834
.5895
.5942
.5298
.5377
.55%
.5669
.5727
.5622
.5360
.5435
.5640
.5710
.S167
.59L5
.5651
.5910
.5955
.5329
.5405
.5430
.5609
.5747
.5629
.5806
.s929
.5391
.5463
.5662
.5730
.5787
.5869
.5926
.5969
.625-11
.625-12
.625-16 #
.625-18
.62520
.625-24
.625-28
.625-32
.5970
.62oo
.6270
.633o
.6420
.6490
.6540
.60~
.6241
.633s
.6373
.6459
.6520
.6566
.6001
.6219
.6294
.6352
.6436
.6495
.6540
.6057
.6262
.6335
.6392
.6476
.6535
.6580
.6029
.62U
.6314
.6372
.6454
.6523
.6554
.608S
.6264
.6355
.6412
.6494
.6551
.6594
.687+12
.6875-16
.6e73-le
.687520
.687>24
.6875-28
.~7>32
.6420
.66oo
.6820
.6900
.6960
.7230
.7160
.6481
.6652
.4866
.6940
.6998
.7145
.7191
.6449
.6626
.6644
.6929
.69n
.6513
.6680
.6887
.6960
.7017
.7160
.7205
.6481
.6653
.6065
.6939
.6997
.n36
.7179
.654s
.6707
.6908
.6980
.7037
.7176
.722.9
.750-10
.75C-12
.750-16
.75C-18
.75C-20
.750-22
.750-32
.722o
.7450
.757fJ
,7580
.7740
.7790
.7276
.7491
.7565
.7623
.n70
.7816
.7254
.7602
.7745
.n90
.7303
.7512
.7585
.7642
.7785
.7830
.7276
.7490
.7564
.7622
.7761
.7804
.7329
.7533
.76o5
.7662
.-2801
.7044
.622512
.8225-16
.222518
.8225-20
.8225-28
.W25-32
.7550
.7850
.7980
.8070
.8150
.B21O
.12.360
.8410
.7614
.7900
.8022
,8116
.B190
.8248
.8395
.8441
.7580
.7874
.8000
.8094
.8169
.8227
.8370
.0425
.7647
.?926
.8045
.8137
.8230
.8267
.8410
.8455
.7614
.7900
.8o23
.6135
.8189
.8247
,8306
.8429
.7681
.7952
.8068
.8156
.8230
.8287
.8426
.8469
.875-9
.875-12
.875-14
.875-16
.875-18
.875-20
.875-20
.875-32
.8470
.8700
.8830
.0990
.9040
.8524
.8741
.8973
.9020
.9066
.0699
.8739
.8852
,8995
.9040
.8550
.8762
.0892
.9035
.9080
.0521
.8740
.8872
.90U
.9054
.8575
.8783
.8932
.9051
.9094
.9375-12
.9375-16
.9375-20
.9375-28
.937+32
.5670
.712U
.7165
.nii
47
Source: http://assist.dla.mil -- Downloaded: 2024-05-14T13:44Z
Check the source to verify that this is the current version before use.
—
‘“
.50C-12
.500-13
.500-16
.500-20
lSi3U?
11.A.4- 3@mmemW
Me sizeM&its bzforethreadfrqfordifferentlerqthzof qagemmt, scacdacd
.Mfied md ~
~ t32re2&,chzss33 (see30.1)IJ - -~~
,. ..
z.
Hirnr dimreterof internaltk.s s
●
Wdl-la3 size In inches
aldtlu.xrMper&ch
2/
Fwca-.&
5sries
Lkignrttim
of
16ZL131US
‘nuerd
2
1
3
4
5
FerQntY
of
nued
6
in
1.000-8
l.om-lz
1.000-14
1.00U-16
I.me-u
1.Ore-20
l.mo-a
1.OCC-32
w
LP2F
m
lWN
UmP
2m
Jam
1.0426-0
1.0632?-22
1.0623-14
1.0623-16
L.0625-26
1.062!+20
1.06.2!+26
83.1
83.1
83.0
83.B
83.1
03.1
S4.1
83.8
.E797
.9198
.9335
.9400
.9600
.9531
.9676
.97L9
74.1
74.1
73.8
72.9
72.1
71.3
69.8
69.2
.9370
.97m
.9850
.9950
63.4
83.6
83.5
83.1
83.B
03.9
83.0
.9623
.9823
.9940
1.0033
1.0105
1.0162
1.0303
7d.1
74.1
73.8
72.9
72.1
71.3
69.8
loom
1. Oow
1.0240
1.225-7
1.123-s
1.325-32
1.12S-16
1.US-1a
1.12.%24
1.226-28
m
Km
W4F
lm
m
2@.6i
2S.7N
1.2.S7H
1.2s73-12
1.167>16
1.1876-16
m
lm
la
w
2um
1.0320
:.0970
1.1200
1.1270
1.1330
1.1490
83.4
83.6
83.1
63.s
83.9
83.0
1.0672
1.1073
1.12S3
1.1355
1.1U2
1.E51
74.1
?4.1
72.9
mc
am
LQr
1.0950
1.1150
1.1600
1.18m
1.1900
1.1960
1.2110
83.5
63.1
83.1
83.8
03.1
23.1
84.1
1.3125
1.1297
1.169S
1.190s
1.3980
1.m37
1.2176
14.1
74.1
14.1
72.9
72.1
71.3
69.8
1.1770
3.22m
1.2450
1.2520
1.2528
1.2740
a3.4
83.6
83.1
03.8
83.9
03.0
1.3.922
1.2323
1.2533
1.2KD5
1.2662
1.2801
74.1
74.1
72.9
72.1
71.3
69.S
1.367 s-m
1.1873-26
1.350-7
1.LE.O-8
l.mu
1.250-16
I.nc-in
1.250-20
1.250-26
lRN
mm’
2m
1.3226-8
1.3326-32
1.3225-16
1.3123-24
1.3125-20
1.3323-26
see
.8650
.9100
.9230
.9320
.940d
.9460
.9610
.9660
e3.5
83.1
83.1
83.8
e3.1
83.1
84.1
-34.1
74.1
14.L
12.9
72.1
71.3
69.8
%:
69.8
1.37+6
1.373-8
1.376-12
1.373-16
1.373-18
1.375-20
1.373-28
ma
am
m
lKN
UNm
‘3uLN
2m7N
1.39s0
1.2400
1.2850
1.3070
1.3160
1.3210
1.3360
83.1
83.1
63.1
83,8
83.1
63.1
84.1
1.2346
1.2547
1.2948
1.315=9
1.3230
1.32s7
1.3426
74.1
74.1
74.1
72.9
72.1
71.3
69.6
i.4373-6
1,4315-8
1.4373-12
1.4375-16
1.4373-38
1.4376-m
1.4376-20
a
m
Uz31
lQ.7N
mm
Zfxm
2MN
1.25’70
1.3020
1.3470
1.3700
1.3770
1.3830
1.3990
83.4
83.4
03.6
83.1
03.6
83.9
83.0
1.2771
1.3172
1.3573
1.3703
1.2855
1.3912
1.4051
74.1
14.1
14.1
72.9
72.1
71.3
69.6
fwbwtes
at erd
tie.
48
Source: http://assist.dla.mil -- Downloaded: 2024-05-14T13:44Z
Check the source to verify that this is the current version before use.
I
I
22!&E 11.A.4 ; ~
tule Size limits befnre thre.dq
13nifiedad snm W
thzezdz, c3dss 3
Iule size Ltiits for differentk
m
d
Inclldlng0.320
@r different kqti
(3ee 30.1) lJ - m~~
)JDve 0.330 thru 0.670
AtOw o.6m tflc”1.50
bird
size in fnches
ard threadsPL?ri.mh
Mnimm
mximm
Rlnim.m
Faxham
!linimm
mximm
7
8
9
10
32
12
1
.8:0
.9100
.9220
.9320
.94M
.9460
.9610
.966o
.0s2
.9148
.9271
.9366
.9440
.9498
.9645
.9691
.8:4
.9123
.9269
.9344
.9U9
.9477
.9620
.9665
fn
.8759
.9173
.9293
.9387
.9460
.9517
.9660
.9705
.8%.
.9148
.9271
.9365
.9439
.9497
.9636
.9679
.8:7
.919B
.9335
.9408
.9400
.9537
.9676
.9729
1.00+8
1.000-12
1.00W14
1.00v-16
1.OM-lS
1.000-20
1.OW-26
1.000-12
.9270
.97m
.9850
.9950
1.0020
1.0020
1.0240
.9347
.9773
.9B96
.9991
1.0065
1.0123
1.0270
.9309
.9748
.9874
.9965
1.0044
1.0102
1.0245
.9364
.9798
.9918
1.0012
1.0085
1.0142
1.02$25
.9347
.9773
.9896
.9990
1.0064
1.0123
1.0261
.9422
.9833
.9940
1.0033
1.0105
1.0162
1.0301
1.0S5-9
1.062S-12
1.0435-14
1.062516
1.0635-18
1.0625-20
1.0625-28
0.9700
.9900
1.0350
1.0570
1.0650
1.0710
1.0860
0.9790
.9972
1.0398
1.0616
1.0690
1.0748
1.0095
0.9747
.9934
1.0373
1.0594
1.0669
1.0727
1.CS70
0.9833
1.0009
1.0423
1.CK37
1.0710
1.0767
1.0910
0.9789
.9972
1.0398
1.0625
1.0689
1.0747
1.0886
0.9075
1.0047
1.0448
1.0658
1.0730
1.0787
1.0926
1.125-7
1.3258
1.12512
1.22516
1.125-3.6,
1.125-20
1.133-28
1.0597
1.1023
1.12U
1.3333
1.1373
1.2.520
1.0559
1.0998
1.1229
1.1294
1.3352
1.1495
1.0634
1.1048
1.1i52
1.1333
1.1392
1.3.335
1.0597
1.1023
1.3240
1.3314
1.1372
1.2.5U
1.0672
1.1073
1.1343
1.1355
1.1412
1.2551
1.1875s
1.3675-12
1.187516
1.2272-32
1.1075-20
1.3.87+28
1.1040
1.1222
1.1648
1.3.s66
1.3940
1.:998
1.2345
1.0997
1.3284
1.1623
1.le44
1.1929
1.1977
1.2120
1.1083
1.1239
1.1673
1.1887
1.1960
1.2017
1.2160
L.1039
1.1222
1.164s
1.3S65
1.1939
1.3997
1.2136
1.2225
1.1W7
1.1698
1.1908
1.1980
1.2037
1.2176
1.250-7
1.250-0
1.25C-12
1.350-16
1.2X-18
1.250-20
1.250-28
l.lno
1.2220
1.2450
1.2520
1.2ss0
1.2740
1.1047
1.2273
1.2491
1.2S65
1.2623
1.m70
1.1809
1.2248
1.2469
1.2544
1.2602
1.3745
1.1884
1.2298
1.2522
1.2585
1,2642
1.2785
1.1847
1.2273
1.2490
1.2564
1.2622
1.n61
1.2922
1.2323
1.2533
1.2605
1.2662
1.2801
1.3125-8
1.31>12
1.312516
1.31~25-le
1.312520
1.3135-28
1.1950
1.2400
1.285o
1.3070
1.3150
1.3210
1.3360
1.2046
1.2472
1.2098
1.33.36
1.3190
1.3248
1.3395
1.1996
1.2434
1.2873
1.3094
1.3169
1.3237
1.3170
1.2096
1.2509
1.2923
1.3137
1.37.:0
1,3267
1.3410
1.2046
1.2472
1.289S
1.3133
1.3M9
1.3247
1.33B6
1.2146
1.2547
1.2948
1.3158
1.3230
1.3287
1.3426
1.375-6
1.373-8
1.375-12
1.37516
1.375-18
1.375-20
1.375-28
1,2570
1.3020
1.3470
1.3700
1.3770
1.3030
1.3990
1.2671
1.3097
1.3523
1.3741
1.38s
1.3873
1.4030
1.2622
1.3059
1.3490
1.3719
1.3794
1.3852
1.3995
1,2721
1.3134
1.3548
1.3762
1.3835
1.3092
1,4035
1.2671
3.3097
1.3523
1.3740
1.3814
1.3872
:.4011
:.2771
1.3172
1.3573
1.3783
1.3855
1.3912
1.4051
1.4375-6
1.4375-E
1.437+12
1.4375-16
1.4375-18
1,4375-20
1.4375-28
See fcotmtes
stardard
, .,
~ of~t
e
I
of engqeuent,
at end of *e.
49
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Check the source to verify that this is the current version before use.
FED-S’IWH2i3/Z3
Imle size limits &fore thretiimg for different lerqths of erqagecent, stamdrd
‘27WLE11.A.4 - maurendd
Unified UX5 scue m
thmaka, *
38 (.80230.1) ~ . ~tin~
.- -.
.=
..
..
nternd thred3
fAmina3sizo b, Ltis
C.n5threadspesindl
Y
%, ies
im
designat
9wmltY
of
mrezd
2
5
~
ox
1.5470-6
1.500-8
1.50C-32
1.500-16
1.600-28
1.50C-20
1.50C-28
6
L3
1.3200
1.36S0
1.6200
1.4320
1.4400
1.4460
1.4610
83.1
83.1
a3.1
03.8
03.1
83.1
84.1
1.33%
1.3791
1.63s8
1.440a
1.4480
1.4537
1.4636
74.1
74.1
74.1
72,9
72.1
71.3
69.8
1.3820
1.42m
l.zom
1.5080
63.4
83.4
03.6
83.1
83.8
83.9
1.4023
1.4422
1.4823
1.5033
1.52n5
1.5162
74.1
74.1
14.1
72.9
72.1
71.3
1.625-6
1.625-8
1.625-13
1.623-16
1.625-18
1.625-3Q
1.44;0
1.4900
1.5350
1.5570
i.%%
1.5710
83.1
83.1
83.1
03.8
83.1
83.1
1.4646
1.5047
1.5448
1.5659
1.5730
1.5787
74.1
14.1
74.1
13..9
72.1
n.3
1.6875-6
1.6875-8
1.6875-11
1.6875-16
1.687518
1.6875-20
1.5a70
1.5520
1.5970
1.6200
1.627o
1.6330
03.4
83.4
83.6
83.1
83.8
83.9
1.57/1
1.5672
1.6073
1.6383
1.6355
1.6h12
74.1
74.1
74.1
72.9
72.1
71.3
1.5340
1.s700
1.6350
1.6600
1.6am
1.696o
83.1
83.1
83.1
83.1
83.8
03.1
1.5575
1.58%
1.6297
1.6698
1.6908
1.m31
74.1
74.1
14.1
74.1
72.9
71.3
1.632o
1.6770
1.7220
1.7430
1.7580
83.4
83.4
83.6
83.1
83.9
1.6521
1.6922
1.7323
1.7533
1.7662
74.1
14.1
74.1
72.9
71.3
1.695o
1.74m
1.7850
1.8070
1.8210
03.1
83.1
83.1
63.s
83.1
1.7146
1.7547
1.7940
1.815%
1.8287
74.1
74.1
74.1
72.9
71.3
1.1510
1.8020
1.8470
1.8100
1.8830
83.4
83.4
83.6
83.1
03.9
1.7771
1.0172
1.8573
1.8783
1.B912
74.1
74.1
7<.1
72.9
71.3
03.5
83.1
83.1
83.1
83.6
83.1
1,7061
1.83%
1.8797
1.9298
1.9408
1.9537
74.1
74.1
74.1
74.1
72,9
71.3
83.1
2.0033
72.9
W8
IO@
16WN
m
m
m
1.5635-6
1.5625-6
1.5625-12
1.5625-16
1.5625-18
1.5625-20
&m
lmll
la
In&P
2L2m
1.75C-5
1.750-6
1.75C-8
1.750-12
1.750-16
1.750-20
UC
1.B125-6
1.8125-8
1.Lu26-12
1.8125-16
1.8125-20
ml
1.m25-d
1.6325-6
1.8125-22
1.6225-16
1.0225-20
L%
mm
m
12LN
lam
2LI.54
13W+
lam
lam
2ow4
1.9375-6
1.9375-0
1.9375-12
1.9375-16
1.9375-20
1.47m
1. 49s0
2.00C-4.5
2.000-6
2.MO-8
2.000-12
2.000-16
2.000-20
m
m
m
201M
1.7590
1.820U
1.S650
1.9100
1.9320
1.9460
2.0623-16
w
1.9950
lam
lam
Se8 fcotnotes at ez-dof talzk.
50
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Check the source to verify that this is the current version before use.
FEE+lD-H28/2B
‘mEG? 11.X.4 - ~
●
bale size 1 hits before threading for different lengths of engagement, starxkd
Unified ard U2G threa5s, class 30 [see 30.1) ~
- -t~~
—
—~ed
hale size Mm.@
k
fur difierent 1,
0.33D W“
0.6772thm 1.50
NAn?.1size in &s
ard thmods per tih
?
10
12
m
~—
-
~
1.3296
1.3722
1.4148
1.4366
1.4440
1.449e
1.4645
1.3246
1.3624
1.42.23
1.4344
1.44L9
1.4477
1.4620
1.3346
1.3759
1.4173
1.A387
1.446o
1.4517
1.466o
1.;96
1.3723
1.414B
1.4365
1.4439
1.4497
1.4636
1.3396
1.3797
1.4198
1.4400
1.44ed
1.4537
1.4676
1.50C-6
1.500-8
1.50C+12
1.50C-16
1.500-18
1.500-20
1.5oo-2e
1.4270
1:4720
1.4950
1.5020
1.5080
1.3922
1.4347
1.4773
1.4991
1.5065
1.5123
1.3871
1.4309
1.474e
1.4969
1.5044
1.5102
1.3971
1.4324
1.479e
1.5012
1.5085
1.5142
1.3922
1.4347
1.4773
1.4990
1.5064
1.5322
1.402L
1.4422
1.4822
1.5033
1.5105
1.5162
1.5625-6
k7625-e
1.5625-12
1.s623-16
1.562518
1.56>2S
1.4450
1.4900
1.5330
1.5570
1.5650
1.5710
1.4546
1.4972
1.539e
1.5616
1.5690
1.5?48
1.44%
1.4934
1.5373
1.5594
1.5669
1.5727
1.4596
1.6009
1.5423
1.5637
1.5?10
1.5767
1.4S46
1.4972
1.539e
1.5635
1.56e9
1.5747
3..4646
i.5047
1.5446
1.5658
1.5730
1.5787
1.625-6
1.5070
1.5520
1.5970
1.62U0
1.6270
1.6330
I.wf
L.5597
1.6023
1.6241
1.63=
1.6373
1.5222
1.5559
1.599B
1.6239
1.6224
1.6352
1.5223
1.5634
1.6048
1.6262
1.6333
1.6392
1.5171
1.5597
1.6023
1.6240
1.6314
1.6372
1.5271
1.5672
1.6073
1.6263
1.6355
1.6422
1.607H
1.6075-.9
1.6275-12
1.687$-16
1.6675-18
1.6675-20
1.5340
1.5700
1.625o
1.6600
1.6820
1.6960
1.5455
1.5796
1.6222
1.6648
1.6e66
1.6998
1.5395
1.5746
1.6184
1.4623
1.6844
1.69n
1.5525
1.5S46
1.6259
>.6673
1.6887
1.7017
1.5455
1.5?96
1.6223
1.6640
1.6865
1.6997
1.5575
1.5E96
1.6397
1.6698
1.6908
1.7037
1.750-5
1.75+6
1.750-8
1.750-12
1.75C-16
1.75C-20
1.6320
1.6770
1.72X
1.7450
1.7580
1.6422
1.6847
1.7273
1.7491
1.7623
1.6371
1.6809
1.7248
1.7469
1.7602
1.6471
1.6884
1.7W8
1.7512
1.7642
1.6421
1.6047
1.7273
1.7490
1.7623
1.6522
1.6922
1.7323
1.7533
1.7662
1.8125-6
1.8125-8
i.e225-12
1.822%16
1.0L25-20
1.6950
1.7400
1.7850
1.8070
1.82L0
1.7046
1.7472
1.789e
1.0116
1.8248
1.6996
1.7434
1.7e73
1.8094
1,E227
1.71796
1.7502
1.7923
1.8137
1.8267
1.7046
1.7472
1.7e9a
1.8125
1.s247
1.7146
1.7547
1.7940
1.8L54
1.8287
1.S15-6
1.e75-8
1.e75-12
1.87S-16
1.875-20
1.7570
1.0020
1.8470
1.8700
1.8e30
1.7671
1.8097
1.8523
1.e741
1.0873
1.7621
1.8059
1.0498
1.n719
1.B852
1.7721
1.8134
1.e548
1.8762
1.8892
1.7671
1.0097
1.8523
1.8740
1.8872
1.7771
1.8172
1.es73
1.a783
1.8912
1.9375-6
1.9315-8
1.937>12
1.9375-16
1.9373-20
1.1590
l.ezoo
1.86s0
1.9100
1,9320
1.9460
~.nn
1.8296
1.8722
1.9148
1.9366
1.9498
1.7661
1.8246
1.e6e4
1.9123
1.9344
1.9477
1.7194
1.0346
1.8759
1.9173
1.93e7
1.9517
1.7728
1.8296
1.8722
1.9148
1.9365
1.9497
1,7861
1,8396
1.8797
1.9196
1.9408
1.9537
2.000-4.5
2.000-6
2.000-0
2.000-12
2.0K+16
2.000-20
1.9950
1.9991
1.9969
2.0012
1.9990
2.0033
2.0625-16
1.2s20
●
P&W
~
in
1.3200
1.3650
1.4100
1.4320
1.4400
1.4460
1.4610
●
0.67u
UAnnm
Minimm
7“
Ch9 of engagemnt
see fmlnotes at end of m.
51
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Check the source to verify that this is the current version before use.
1.625-8
1.623-12
1.625-16
1.623-32
L.625-20 ‘
EED-sm-H213/273
l!ALu.2 11.A.4
●
-.
-“R&rrrdd
hole size limitstefare threadingbr differentlengthsof erqag~nt, st.artiard
Lhifiedad =
W
*e*,
.=3d69= (* 30.U Y - ~~@
tiI
Minimum
diameterof internalthreads
Fercentv
Ferrem&
of
‘Iluead
of
Tluead
6rJN
II
3
4
2.325-8
2.12522
2.125-16
2.125-20
2.1875-16
2.250-4.5
2.250-6
81R4.
Mm
Mm
2orm
II w
II
2.500-4
2.750-4
3.000-4
3.250-4
6
h.
in
2.125-6
s
1.9450
1.9900
2.0350
2.0S70
2.0710
83.1
83.1
B3.1
03.8
83.1
1.9646
2.0047
2.0448
2.0658
2.0787
74.1
74.1
74.1
72.9
71.3
2.1200
83.1
2. 12S3
72.9
2.0090
2.0700
83.5
83.1
2.0361
2. 0!396
74.1
74.1
2.2290
2.4790
2.7290
2.9790
83.4
83.4
83.4
83.4
2.2594
2.5094
2.7594
3.0094
74.1
74.1
74.1
74.1
%
II=
see frxsnotes at eti of Gable.
52
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Check the source to verify that this is the current version before use.
FED-Sl’lH28/2E
w
m
23.A.4=~
--
Me sim limitsbfnre thredhq focdifferent
kqtb of tcq~k,
onifbd8rL2g=tkell&,c&M
2a(00e30.1)J/-amtillw2d
—
~
TO ad
bale slm
iIY%u3~
0.3~
Mni-
II A@ve
&
different luqttm of ~
0.3~ t&U 0.67D
~
II
I124andslx@lnimsEo
-o-~til,=
26nLimmll Mnioma
7
in
h
1.96%
1.99M
2.03n
2.0554
2.0721
1.9s63
L.9P73
2.0396
2.0616
2.0766
10
32
h
1.95%
2.0009
2.0423
2.0637
Z.om
in
in
1.9546
1.9977
2.039s
2.0635
2.0747
1.9644
ZO047
2.OUB
2.0656
2.0787
2.22s-8
2.32s-3.2
2.225-16
2.225-20
i
2.387+3.6
2.3300
2.2262 II 2.3229
2.3262
2.3260
2.2293
2.2C90
2.07m
Z.mn
2.07%
2.0294
2.cm6
2.0226
2.07%
2.m%
2.2539
2.5039
2.7539
3.0039
2.2444
2.4944
2.7444
2.9944
2.2m
2.4790
2.7m
2.9790
2.0361
2.0746
m
II
3f21=dlffe2ambmlht=arecq+dbthemkr
2.0263
2.2594
2.5094
2.7596
3.0094
dXbr2rhr-fc
2.Xu-4
II
II
2.250-4.5
2.2s0-4
2s00-4
:=
3.*
c3aytlmofc~t
bad
hSM3hlg o.3m. ~,t.b~mluesbr
d
hrocr am
pitch ~tmti
thsn o.3m in SIZZ2S0.25 tn.
klgthaoc UqagaEnt gmlk
ti5t62 - tkt Um differertm ~tbeen lidtn is 2eso tkm 0.0060 tn. Fur dbsee
other *
t.lm9Bgiven in this t8b3e, mc 30.2.
Mmiil125(21rRta?r+tctl
.adi=laticmahtlk
41Lbr0tq
QrMrin
va.bs&thiswpm96&2u!er9 iwadk~ikheilnthmin
2k.3eslw
thiatah2e mlyhc&lMrledbyuR0s
tbtaae!
(1) Ulthtbmpiaml
[2)wiuladi=mtAE
ttmtis3es9
bianintI?911J cuultuwal
t3B3dhm@.tec
0itbdt5!EtH-Qiml a&iMtimti
oimk?sdtbml.ooin.~
14ucb &
tin ~
are&sired. ou3z:vahua 3nt.tmtabf0rmalna2
trJw05&tMdpu6me.)
~i
~8aw2.m
m*taint&.
va2mdf0rt&
4.0m3-m3+m thremf. U3f 2.OQO In S2.2m ti &e 2.c@o-m tkueti
6kam Jn the t8b2e. =
Vd83S tudd thn ~:
3.6630, 3.8722, 3.8684, 3.8759, 3.8m2,
3.67P7. mm pantagm
of thread vLu -III
Lmdmqel.
~.cau&d
Offint.hpr&irq
mlum.
100 prxcsnt of thred - 0.75B (m
53
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Check the source to verify that this is the current version before use.
20.2.3).
I
I
I
I
I
l?EIF.SSD-H28/2B
APPENDIXB
—.
--
IE.SIQ4@UNIFIED—~
40. ~.
fiis apg=dix prwides guidelines which rcay be used in the
parts.
It is not a rnardatory
design of unified screw threads for threaded
of
the
standard.
The
information
IXX-Itained
herein
is
intended
for
part
guidance
only. It supplementsinformstim rnntainedin ApperdixB of J@i8 Bi.1-1989.
50.
General.
general,any given prcblem in threaddesignmay te
==@ible
tO ==~
mre
or less Satisfacbxy sdutiona based on the
preljndnaryselecticnof certainelem?ntaof the designand the prcper
In other mrds, threaddesign is to a large
adjustmnt of the O*
elenmw.
extentempiricaland is partiallybasedon previouse~riene
with similar
designsad the j~nt
of & designer. Acmrdir@y, it is not practicable
to presenta definitesystemof approachto the designof a threadedassembly
but nrely b presenta discussia of variousdesign factirs.
50.1
Intrcductim.
In
50.2
Factor relationships.The interrelation
of lengthof engagement,
minimmnmajor diameterof the externalthread,maximumminor diameterof the
internalthread,ard the stre@h of the assembledthrecdneeds to be urriersbrrl ti carefullyconsideredin order to produce tlm?optimumdesignof a
specialthread. It is not eccmunicalta use either a ler@I of threadergage
uent which is longerthan required @.sbor@r than thatwhich will davelopthe
full strengthof the externallythreadedmember. Other factors,such as
controlof tap breakage,prcparseatingof a threadedpart on a sbcul.der,
the
preventirmof cross threading,omditicns of loadingwhen the assenbl.dparts
are not concentric,SIXIpassiblecollapseof a hol.lcw
externallythreaded
mmber, requirecarefulanalysisti adjustmnt of the design with respectto
selectionof the diameter-pitih
curbination,the classof thread,lengthof
en9a9~nt, and major and minor diametertoleran=s.
50.3”Thread fit consideratims. A close fittingthreadassemblytier acme
Ccrr3iticns
may fail,whereasthe causeof failuremsy k elimina&d by
providinga Icoser fit. A cap screw that seats only on one side of the tearing
surfaceorder the hea3 may breakoff when the screw is tightened. Wken a screw
has a largetearingsurfacetier the head or when the head must be squarewith
a projectingpin, sufficientpitchdiameterclearancemust be providedto allrw
for any out-of-aqdareness
of the screwaxis with the bearingsurfaoeurder the
head. Thus, as largea pitch dkuretertoleran~ as pcssible,togetherwith
providingproper toleranceson squarenessof face with the threadasis where
seatingis reguired,may avoid the necessityfor specifyinga heat treated
tmlt.
54
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Check the source to verify that this is the current version before use.
●
??Eo-s!m-H2e/2B
50.4
.Staniardthreads. use of standardthreadsis reguiredin accordance
with 4.●
threads
7— Informationon preferredsizes ad classesbr .sp3cia2
appeSZSin 5.1 and 5.2. Wheneverpracticable,lengthsof engagementfor
cc.srse,
fine, 4, 6 and 8 threadseriesshouldbe tetween5 pitihes1 l/2
diamters; for all other seriesthey shouldte’betwsen“5”
@
15 pitches.
A&i=
theseprincipleswill help keep costs of nwinufatiread gsging
60.
mtriciti
of as-ly
and cross threadinq.
Note: Tat& 6 of Xi&E B1.1-1989 inch.deetabk.s
of “O.375H,0.75H h
H.
In aesemhlyad use, tk crxrbired
kkmnces
ad armarms
on both mating
shouldnot allow threadsto disengagecm o= side W&en assemblyis
eccentric. I’& axis of the internalthreadcan be displacedradiallyfrrsa
coinc~with
*asisofth
ex=nalthread byamaimuntequd
totheaum
of the pitch dizureter
tolerancesard the alkwame. This radialdis#acement
may be sufficient= that the flankom~t
is entirelycm one side ad on the
opposi~ side the crest of the externaltbre~ will bs. in line with tl-e crest
parta
of
the
uternal
in
sti
a ~sition
thread
in a
with
tq@i
the
following
hole:
(1)
results
*
There
will
*
&
screw
danger
is constrained
of
aossiq
the
starting,iux3(2) the screw may @
out of the tole when tensionis
exertedin this constrained~sition. The minimumanuuntof overlapis
arbitraryaml controversial,tit the followinggeneralrule can be used in lieu
of mre specificdata:
threads
in
* the first step to assure tk minim.nnsafe overlapon hth sidestin the
assemblyis amcentr ic, the differencebe~
tl’eminirmmmjor ditmeterof
the externalthreadad the n!axti minor diamter of the internalthread
slmld not te less than twice the addendumof the externalthread (0.75E).
O*rwiae stated,the sum of the major+ iaretertoleranceand allowsnce,if
any, of the externalthreadad the minor-diametertoleranceof the in&xnal
threadshouldnot be greaterthan 4/3 the addendumof thz externalthread,
0.5H. This provides tir a minim.mof 50 percent threadengagement. As the
aeccnd step, to assure that mininunsafe overlapon one side when the assembly
is ~tric,
tte differencebetweenthe nbsximum
pitch dianeterof the internal
threadand th? minimumpitch di.amterof tk externalthreadshouldnot be
greaterthan the basic threadheight (O.625H). otherwisestited,the ~ of
the pitch-diaretertolerancesof troththreadsand the allowance,if any, should
not be greaterthan the basic tfueadheight (0.62513).
This providesfm an
ecxx?ntric
assemblyccmditionequal @ half the beic threadkight (O.3225H)
and zeromini.mmoverlapon cme side. If the resultsfrcm the limitsof size
selectedviolate & atmve rules,the toleran~s shouldbe reducedby using a
closerclass of tolerance,assumingtolerancesconsistentwith nnnufactur
ing
pxsibility, or a marser pitch shouldbe used to increase the amunt of
overlap. The nujor~iameter tileranceof the esternalthreador minor-diameter
toler~
of th internalthreadshr@d not te less than the pitch-diareter
toleranceof tk respectivethread~ maintainthreadform. Also, it shouldbs
noted that, if the toleranceon the minor diarreter
of tbe internalthreadmust
neeeearily be large, &s nmjor diameterof the externalthreadmust be held
close to the msxinummajor diameterad vice versa.
55
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FED-SID-i128/2B
factors.
70. .-Str engtb
that externallythreade3psrts
70.1 Tensilestressarea. Testa have *
fail,in tensinn.atlnads corres@rxiQ in *,
of xntbreaded.parb.
nitb
diamters midway betweenttx?ir
pitch & minor dtiters. Formulas (la)and
(lb)in table 11.B.1providestress area tased upn a diameterapproximstdy
midwaytetkeenmininnnn
pitch diameterand mininn.nn
minor diamter. These
formulashave been applifsl
successfullykY steel.and otier nY2b.Ls
with ultimate
strengthsup to 180,000psi and are often used for productacceptance.mile
stressareas for s=ard
sizes are tabulatedin section11 of =
B1.1-1989.
70.2 Shear areas at minixmnn
material. The gatric
s~ar area of an
in~
threadat minimxnmaterialis ecaualto tb? area of that tbreulwhich
is intersected
by a qlider with a dians&r equal to tbe mininm najor
diareterof the matingex@’nal threadover the lengthof engagznt.
This
is
identifiedin figure2.B.1for a one pitch secticmad formuhs (2S)and (2b)
in table 11.B.1are used for calculation. Simil.srly,
the gemretricaheararea
of an externalthreadat minimummaterialis equal tm the area of that thread
which is intersectedby a cylirderwith a dianeterequal IXJthe maxiusnn
minor
diameterof the mating internalthread. ‘I?& is also identifiedin figure
2.B.1 for a one pitch sectionam5 firnndas(4a)and (4b)in table 11.B.1are
used for Calculatiral.
,.
56
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FED-sTD-H28/2B
TABLE 11.B.1 Formulasfor screw threadstrengthfactors
1-
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FED-!31!wIi2e/2B
II.B.2
TABLB
90cmlh
ic
Kfuueeter iat
mmbm
Iuuilc
[f-l)
(23)
I
Formulasfor screw threaddesign
~
Btresa, ‘zxterd.fy
prt - We fmsim
% -:.
~
tii2a
5:.5:+5
exwrnally
.t.mM,
tfueafd
km
(b) ~
mrmfd
Rferem=
P=$m@
(M)
70.6
a
70.6
&
prxt
2
I
WifbSt - ?
0.7654~d+w]
I
I
+E
I
I
““*g
I
6A: fzm (,d)0,
[13)
Ialgthof
~
rl?3ngEerlt fssrdltul.
*
fAilLUC 0~ ..&d
r.?-
(fb)
70.7.3
~
ad Intellnlfbra
3A; frm (3A)or (lb]
laq’tbOf0qag5mtfssmdqm
(M]
W
70.7.4
m.
.W.
of extxrnc.1 thread
fcus
Na) or
(w
(k.)
(fb)
fts
2A” fzlxl
[16)
or
70.7.5
of ergLgrs51t fused up
dQR3@ng fu12 tendle tieqth
of exturn, t.hmrd Wifb tfuti
●t -ic
Si’Z3 - W
vitb [161
12—~
M
m*Ofew+f==ntwA?arofintmnalfmuld
Iz-Izfrcm[Elx
Ia-@fl
(M)
frmd Mb)
tms
\
%7.5
LEEu
~ m
(9)
form (-
K+inl . im=h.
isgremcrtfml
)
k
,
I
I
fbmtim:
dpim
- mfnimnl mlmr dirllmtic,
xndmub
dh . me
diawter,
external
thcead,
flat
[12),dl.nin-d+-~fl-d~-~
eat.crrmlly tfxe?ded put,
inch.
If tic, is M tie, db - Q
58
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FEtWlWH28/2S
I
I
m
MAXIMUM MINOR OIAMETER
OF lNTERWAL TNREAO
sEmoNmMIN,M”M
I
SHEAR
I
AREA OF
INTERNAL
TNREAD
““’”’ ‘
MINIMUM MAJOR OIAMETER —
OF EXTERNAL
TNREAO
70.3 Shear areaa at basic size. The gearetric*ar area of an exkwnal
a=ic
size is equal
to tke area of a basic size threadwhich is
intersectedby a cylinderwith a dianeterequal to the basicminor diameter.
Formulas (6a)and (6b)of tible11.B.1are used fir calculation. ‘Fhsgecznetr
ic
shear area“ofan ~te&al threadat tasic size is not ordinarilyused for
calculations.
thread
Shear area simolif&~ formulas. ‘mnnulas (3)and [5) in -le 11.B.1
are sinipli
fied fornud.as
for Internal ad external thread shear areas. They are
based upn aqirical dati ad give shear areas whichvary frmn the gecan?tric
test dab agreesnxxe clmely
minimummaterialshear areas. In sczne-s,
with thesesimplifiedformulashearareas than with gecmstricsheer areas.
70.4
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59
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FED-S’i’WH2E/2B
70.5 Shear area, cabined failureof externaland internalthreads. When
the mstfng externaland internalthreadsare a parts Imnufacturedfran
materialsof a~roximstely equal strength,failurewill usuallytakeplace in
toth threadssimultaneously.Thread bendingduringfailurecharxp the thread
geometryin this mae sc that effec$ivesheararea is significantly
saaller
than tise -lculated fran formulasdiscussedin 70.2, 70.3 ard 70.4 above.
Formula (7) in table 11.B.1 is an ~irical formulawhich gives an approximate
equivalentfor this case. Numerically,it describesa failureat the pi&h
diamter of one of the threads.
●
70.6 ‘l@ns.ile
stress. Formula (1.1)
in table11.B.2 is often used for
acceptanceof externallythreadedfastenerswith ultimatetensilestrength,
yield strength,or rare other selectedstresslevelappliedto St in order b
determinethe requiredaxial test load. When threadsare used in a joint,a
tightening
torque
is applied
to overfrict ion, ard to develop
overthread
in a shear
stress,
which
load,
causes
an increese
friction
tier
a tdt
the axial
lcasd.
This
head or nut, b
torgue
results
when tiined
with *
tensile
stress
fran *
axial
Etxmula (12)in
in the effective
tensile
stress.
=e
II.B.2describesthis situation. Experien~ has slxnm that for a solid
externallytbrerdedpart, the ccmbinedstressis generally*ut 20% greater
than * tensilestresscalculatedfrcxnforrmd.a(n). Therefore,in this case,
the crrnbined
stress is often assuuedto be 1.2S or is not considereddue b
SStisfact.myexperiencewith tbe Facimrof Safe& used.
70.7
Lenqth
of engaqem?nt,LE.
●
70.7.1 If failureof a fasteningsystemusing stardardthreadedfasteners
shculdomur it is generallynure ecommical tit the externallythrezuied
part
will break ratir than that eitherthe externalor internalthreadwill strip.
In other mrds, the lengthof threadengagenmt stxnild
& sufficienttn devel.cp
the full strengthof the screw. ‘Ihua,the lengthof internalthresdard the
diuensirmsof this thread,particularlyits mimr diameter,shouldbe such
that, takinginto acrmunta pxsible differen~ in strengthof materialof t&
internalad externalthr.swls, the threaded pxtion of tbe externallythreaded
paxt will break before eitbsr the external or internal threads strip. Due to
this situation, lengths of engagement formulas are dez ived fr.an shear fornulas
with tensile stress area ~ replaced by X
because the reguired area in
skar is twioe tlBS tensile stress area in order b develq the full strength of
*
externally threaded part. This relationship is baaed upm experkmts
mile
by tbe National 3ureau of Sta.r&rds in 1929,
in which it was foundthat for
kt-roll@ arxlcold-rolledsteel,and brass screwsand nuts, this factorvaried
fran 1.7 to 2.0. The effectof ccmbinedstressis not tiken into acmunt in
calculationof 12?becausethe added @ear lcxd affectstoth tensileard shear
stressesin approximately
the Sanb2 prqrtion.
●’
60
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EwsmB28/m
70.,? :2, All
Iimmlaa
-r
@gth
of engag-t, given‘intable11.Bi2yield
apprQX_te Val= Since they are based in part upn shear areaswtiic.h%re
not
exact due to nut dilatim which varieswith gmtry,
frictionforrs, ard
materialproperties. Also, the effectivemss of partialthreads,in *
countsrsinkfi
~or dmnifer6)ciitliie*” of the intird thiead,‘isiiitalways
the Smle. For calml.atirxu3,
approximatiy ba.lfthe crxmtersinkd@I may te
ccmsideredin the -length
of ~t.
It is advisablethat ~tirms
of
lengthof engag~t
and correspx-ding hd capabilities
of a threadedjointbe
cheokedby actual tests,for criticaljoints.
70.7.3 Wls?nthe ex~y
ad internallythre?skaputs are made frrml
matir*
of approximatelythe same strength,requiredlengthof engagauentin
formu2a (2.3)
of table II.B.2may be applied. This assumesa cmthatirzl
failureof both threads (see70.5).
70.’7.4When *
internalthreadmaterial.lv
exceedsthatof
of engagementin form&
(14)of table
II.B.2uay be spplied. !RIisassures shearof the externalthreadd uses the
gecmetricshear area of the minimumexternalthread (see70.2) . A slightly
I.mgeror abrter lengthof eng~-t
will te fiicatad if the simplified
formula (5) in Uahl.e11.B.1 is used.
*
external
thread,
strengthof *
r+ired
kr@
70.7.5 When the strengthof *
externalthred materiallyexceedsthatof
the internal thread, reguired hrqth of engag~
in @rmula (16)of table
11.S.2 is used. This is based qxn the internalthrezdstrippingload M.ng
equal b the ncminalexternalthred stri@ng load which will develcpfull
strer@ of W.externally,threadedgmrk. Zf &
ia.Jaas.thsn.1,see
70.7.4ard if approximetilyequal to 1, see 70.
7.3.
70.7.6 For an adjustfigor lead screw of if the ~ctim
will be
frequentlyunscrewed,* *ulsted
IE simuldbe increasedto a.1.kwfir the
e~titear
On * flanksof *
threadsduring tk usefullife of tbe
.
I
I
I
I
“~0.?17:For”t&ed)n2es”in ahi?et”
*M,
,* kinum size of th6’screwto be
~ifid
stxd.d b such”that the thicknessof sheet equak the LE requiredto
deve@ full StKel@h. In order to use the largestpssible screw,it is
n~ssary that tbe tolerance,~,
cn the minor diameterof * b.la slx.ndd
be * practicalminimun. If it should“prove.ti& inpracticahle
to reduce tk
diametertoleranceb such a vslue, it may be n~
to decreasethe
inimr
minimumminor dizmter of tl16internalthre~ arxlto increasetb minor
i6 daqa,.
.tlp.Jmximum
@BJK
dbtar
bleranca by the:=
arxnant.If this..
di,amStar
of t.hsscrewmust be reduc@ ~“ th ~
auxwnt to prevent
interfermce aIX3the.rniuxdianeterof the ~ threadring gage must likewisete
decreiisd,as this is W cnly controlof the minor dianeterof the screw. In
all awh cases, wtw?redimensionsare alteredfrrznthosecalculatedacmrding to
tk standard,the threadas.bu.ld
be designatedas specifiedin sectirm6.7 of
AQ4?.B1.1-2.989.
I
o
.
..
61
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FEESTD-H28/28
~r’ retainingus
iiishafti“tie * ‘**
aiial firce
70j.&
resi-by
the collar is appreciablyless then the tensilefir02 that““the
shaft iiself is“capableof resisting,LE need orilybe lcmg etx)qh b withstad
the expec~ axial.forcgw the mllar. If,FC is.QK axial..for~.
.@...@.
carriedby the mllar, UIS~ is the tensilestrengthof the shaft ad W1’Sn
is the tensilestrengthof the collar,calcolatethe requiredlengthof
engagenrmtfran one of the followingfornmlas:
Z?c
a.
ColJ.ar thread
strip: I.E=
~
x ASn from (2a), (2b)or (3)
.—
LE
2??=
b.
Shaft threadstrip:
LE =
L71S5x ASS fran (4a), (4b)or (5)
z
c. Cmkinatirm threadstrippingwhen WIS.s= W1’Snapproximstily:
2FC
~.
UIS5 or WfSn x X
frrxn(7)
-FE
Note: Numbers in
parenthesis
are
&mmila
v’mmters
,frcxn
table 11.B.l.
For I_dlow,thin wall threadedperts as the wall thicknessof either
internal
ad
externalumbers-~s
thin, the temkncy of tlE
external
mmker
WY enlarge
ad
the internal
Xremker to neck dcnm in *
threcd
means thatsn I.Egreaterthangiven by fornulamustbe used, also that the
tilersnceson minor diane@r of the intxmal threadard major diamti of ths
external‘thread,~
ad ‘M, must be smll to obtain * maximumpracticable
depth of threadengagement. For cxqanents having~eeds on thin-selltubing,
tests@e? actualtmrkingconditionsslmld be made ti determineprqer
selectirnof wall thicknesses,lengthof engagement,and pitch of thread.
70.7.9
or bth
the
80. l’bredm-qxxtims
in relationto tapping.
80.1
In the productionof threadsit is rxms.idered
impracticalto tap a
threadunless its nmninaldiameteris greaterthan six timss.the lxsic thread
height;therefore,wtr?nti ratio of D to h is less than 6, tk use of a larger
diamter, a finerpitch of ~e@,
or both, s~~d te mnsidered.
is a factor in cmtrolling tap breakage. Tap breakage
80.2
‘l’he size of
is infrequentif the9 larm2tir
of the tap is over 0.5 in. or if the lengthof
threadto be tappedis less than 0.5D. For sizes less than 0.5 in. and length
that
of threadover O.5D, tap breakagecsn be minimizedby use of a large ~
is ~
trash.
Howsver,thismeans thatLE may have to be increased
developthe full strengthof * screw.
62
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FEO-8TD-H28/2B
,.
90.--Bxal&s Rf.hreaddesim.
.
:
.. ....=
.,.90a ‘&m &rel thread. A gun barrel is subjectedb an internalexplosive
pressurethat producesa tensilestressin the threadederd. The lengthof
~~t
of the ~
~
be -SUfficient‘toprcducea &*
-~ea in
shearon tk threadsof tk e.crm in line with the mi.mr di~ter of the tap~d
FOle thred.sequal to twice * stressarea of the threadedporticnof *
barrel. Assume that *
thread on the barrel is 1.500-8aN-fiad the minimum
internaldiaus?ter
of the baxrel at tte threedederxlis 0.792 inch.
I
Note: 8ymbol KAaticm
ard fornuib
accordancewith tables 11.B.1 ad 11.B.2.
a. Pe@red lengthof engag~t
l?dl.ow
part.
~
.
numters
in
parenthesisare in
is titi using formula (14) fix a
2 (As - o“7fJ54d;
)
= 0.7854 dw
(
\
read as
with ~
- 0.9743 2. In this case, As may te
\
ni
1.492 fron table13 of ASM3 B1.1-1989.
dh = 0.792
n
. 8
%=
= 1.390 fran table 34 of ASME B1.1-l!389.
d@n
= 1.4093fran tah.le3A of ASME El.1-1989.
b. Calculatingfrcsnthe atnveyields a requiredlengthof eqagemnt of
0.777 inch. By reducingthe internalthreadmi.mr diameter
toleranceby half, the resulting nsu is reducedto 1.3775
inches,zud the reguiredlengtho? engagemnt is reducedto 0.714
inch.
63
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screwsnmmt@
bracket.b Cask irm part. lb dimeosirm.iarequired
.——
for the largeststsae.1
asp Z=
tit can.k@used .tobald a ,bracketon ,a.uaat
ira-:x@. ‘@e tgrisile
strengthof the steel is 60,000psi, the t@aile
strerigti
“ofthe cast iron 20,000psi, SIXIthe thiclmessof the cast iion is
sti that the lengthof threadcmgageanenk
canmt exceed1.750 in. Tbe screws
-.on*
*.eide *f--ti-ba!*”wilJA-iJl-tassios. ---.
------’
-------------------,, ...
..
..,., ... ,..
....... .. .
~te: .Symbl mtatinn and formulanumbers in parentbesiaare in
=rdane
With tables11.B.1ard 11.B.2.
90.2
a.
●
tkexkrnal
threadnxiteridis considerablystmqer than
that of the internalthreadmsterial,in -rdanCz
with 70.7.5,
formula (16)wi.U te used to d.culdte the lengthof engagement
required. This Ermmil.a
is appliedfor LE tased upn shearof the
internalthreti. ‘R3rmnfirm this asswuiptim,Ij4
shouldbe
Since
Calculated.
b.
Rl cannot be calculatedfrcm formula (8)until a threadsire is
selected. BY definitim, however,R1 is *
ratioof ex-nal
threadshear area ti internalthreadshear area. M approximation
of RI, ran be readeusing * simplifiedformulasfor shar
area5 so
ApproxhsNz R1 .
c.
~
is calculatedfran fonrnd.a
F&Ida
(5)
.
0.833
ZziEm
(9).
U&
%=
d.
~;=-
=0.333
Fran b end c abve, R1/R = 2.5 approximtdy. This *W
being greaterthan 1 m z“
mm tbe use of formula (16) for
calculationof lengthof engagement.
. .
e.
. .
(16)it is seen that * lengthof engageumt must
formula
k approximately2.5 timesas lmg es that requiredif shear in
the externalthreadwere tke omtrolling factor. Thusr Since *
maximunavailableLE is 1.750 inchs, the approxiOataLIZrequired
for tbe screw to develrpfull strengthis 1.750/2.5
= 0.700
inch.
Fran
f. J.mmuch as the hole is tappedin cast iron,a relativelycrarse
threadmuld be reguired,that is W
or coarser. The mat
readilyavailablescrewsvmuld be UK. Select threadsi7-esfran
figure2.B.2which yield LE of a~roximately 0.700 inch. Figure
2.B.2 was devel~
fron formula (1.5).
For 1’ - 8uK, LE/D = 0.594and LE = 0.594
For 1~8
7’UK,LE/D = 0.592 (est.
) and U? = 0.656
For lL - 70’N2,
L@
4
= 0.600 (est.) and E
64
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= o.750
I
EZD-S7TD-R28/2B
!0
I
h. The threadskouldke checkedin zciwrdancewith formula (16).
Formula (16)may be exprb
as follcws:
3.1416~min XL
4
(
with ~
= 0.7854 db
be read
as
- 0.9743)2. In this case,As IMy
-
‘}
\
0.763 frr.en
tahl.e8 of ASMR B1.1-1989.
r+lnin= 0.970 fran table 34 of ASME B1.1-1989.
FOrIIU.&I
‘1 = Fo@
.,.
.
. ..
(6b). +X%*
. . .
.!n ihnin:
Lax. 0.57735
[
(dQin
;-
I&sax)
1
n=7
dmin = 1.1064 fran ixib.le
3A of ?!SkiE
El.1-1989.
D2max = 1.0416 fran We
3A of M24E B1.1-1989.
so R1 = 0.863
RI
.
0.333
fK!IUC *W.
i. Calcuhting frmn 0s atme yieldsa requiredlengthof engagement
of 1.729 inches. This is acceptablesince it is less than the
masimumavailableengagmt
lengthof 1.750.
I
65
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FED-Sl!D-H28/2B
(-4
!3
E
tmmwcammmmm
m msttn
‘am
66
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P’EMm+w29
..
-
APPENDIXC
..~ _=-,
.. ...
AMERIC2N NWX2QLFWU4CF
THREAD
100. ~.
This appsrdixprovid~ gemxal informiticm
‘atimtthe obsolete
Iimerican
Nati.trial
form screw thr~s.
It is not a mardatorypsrt of the
stiard.
See 5.2.1
for eelecticmof atamiardlhified screw threadclassesto
replacethe AnericanNational form threads.
110. Profiles. Basic profile is the same as that of M Unifiedscrew
threadexceptthat the width of the fbt at the root is 0.125P. The design
profile
for internalthreads ia the W
as that of tbe Unifiedscrew thread,
i.e.,
widthof flat at the root is 0.250P.
3.20. ‘llueti classes. ‘here
are 5 cbaees of AmeriainNationalfbrm
threads. Ebr informatirmon Class 5, see FEM?m+28/23, C1.aSS5
Interference-Fit
Screw Threads. See below tir other classes.
120.1 AUowaces.
my Class 1 externalthrede have an alkwmce. Class 4
externalthreadshave a negativealhance on the pitch diametexonly.
Allowancesare ehmm in Table 11.C.1.
120.2
‘lbleran02s.Piti diaretertiler-s
for externaland internal
threadsare .sl’nwn
in Table 11.C.2. External threadmajor diamter bkrances
for Uaaaes 1 ad 2 equal twim their respectivepitch diamebertoleranms; the
Class 3 ad 4 tolerancesare the same as the Class 2. Internalmi.mr diam=ter
tolersrms for Classes 1, 2, 3 and 4 are @
to 0.1 t~s the design
(minimum)minor di-ters.
120.3 Formulae.
per inch.
Note: Pitch, P = I./threads
120.3.J Internalthread.
Min. major
dia. = basic major dia.
Min. pitih dia. = min. major dia. - 0.649519P
Max. pitch dia. = min. pit@
dia. ‘“~
Min. mirxx dia. = min. msjor
dia. - 1.082532P
fr~
TFMe
11.c.2
!@.x.minor dia. = min. minor dia. + 0.1 (min.minor dia.)
120.3.2 Externalthread.
Class 1 max. major dia. = basicmjor dia. - esl franTable 11.C.1
masses 2, 3, 4 max. major dia. = basicmajor diameter
67
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FBHmx328/ZB
Min.
major dia. = max. msjor dia. - ‘I’d
frcanTable 11.C.2.
-..—.=.
Classes
I
Class
1,
4 max.
2,
3 mix.
pitch dia. = max. major dia. - 0.649519P
pitch dia. = ~.
rmjor dia. - 0.649519P+ es
frcnn
Table 11.$.1
tlin.pitch dia. = max. pitchdia. - ‘R32frcsnTable 11.C.2
Max. minor dia. = max. majordia. - 1.226869P
130. Desiqnatims. StandardAnericanNstionalfirm threadsare deaignati
the saue as the Unifiedthreadsexceptthat series i.rxiicatir
dces not we the
“Um and class does not have the ‘Ae or “Bm indkdth
fix “external”or
mintermal=. Thus, a stam3ardthreaddesignaticmmight read ‘1/2-131?l-2m,
br
crmhinatima of
exmple. A seriesdesigmstor‘W” is used for ~ial
diaueters,pitchesad lengthsof engagmnt.
140. -es.
~es are designedin ~rdance
with tte principlesof Unified
thr~ gage design. See ~8/6,
Gages and Gaging fir UnifiedScrfiw
Threads- UN ad UNR ThreadForms.
,.,
,..
I
68
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,.,
I?Ews!m+128/2B
.._.=.
‘““TRBLE 11.C.1- Albwance for AuericanNationilScrew ‘?lhreiuk:
.
Threads“per
inch, tpi
Class
4 negative
allWanCx2 , es4
inch
80
72
64
56
48
0.0007
0.0007
0.0007
0.0008
0.0009
44
40
36
32
28
0.0009
0.0010
0.oo1.1
0.oo11
0.0012
24
20
18
16
14
0.0013
0.001.5
0.0016
0.0002
0.0003
0.0003
0.0003
0.0004
0.0004
0.0018
0.0021
13
0.0022
12
II
9
0.0024
0.0026
0.0028
0.0031
0.0004
0.0005
0.0005
0.0006
0.0006
8
7
6
5
4 l/2
4
0.0034
0.0039
0.0044
0.0052
0.0057
0.0064
0.0007
0.0008
0.0009
0.0010
0.oo1.1
0.0013
10
10
69
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EnHTD-H28/2B
-*
.
11.C.2.-Tolerances@r
Ameria
National
Pibh diaseter tolerarmes
Internaland externalthreads
Threads
class
per inch,
tpi
l“D2/’m2’
1
inch
Screw
Threads
E&r
Y
,,:
1 threada
;laases2,3,4,
Class 2
claaa3
class 4
class 1
Trl.@32
m@32
‘rD#rd2
m
‘m
inch
inch
inch
inch
inch
80
72.
64
56
48
0.0024
0.0025
0.0026
0.0028
0.0031
0.0017
0.0018
0.0039
0.0020
0.0022
0.0013
0.oo13
0.0014
0.0015
0.0016
0.0048
0.0050
0.0052
0.0056
0.0062
0.0034
0.0036
0.0038
0.0040
0.0044
44
40
36
32
28
0.0032
0.0034
0.0036
0.0038
0.0043
0.0023
0.0024
0.0025
0.0027
0.0031
0.0016
0.0017
0.0018
0.oo19
0.0022
0.0011
0.0064
0.0068
0.0072
0.0076
0.0086
0.0046
0.0048
0.0050
0.0054
0.0062
24
20
18
16
14
0.0046
0.0051
0.0057
0.0063
0.0070
0.0033
0.0036
0.0041
0.0045
0.0049
0.0024
0.0026
0.0030
0.0032
0.0036
0.0012
0.00).3
0.0015
0.0016
0.001.8
0.0092
0.0102
0.0114
0.0126
0.0140
0.0066
0.0072
0.0082
0.0090
0.0098
13
12
0.0074
0.0079
0.0085
0.0092
0.0100
0.0052
0.0056
0.0059
0.0064
0.0070
0.0037
0.0040
0.0042
0.0045
0.0049
0.001.9
0.0020
0.0021
0.0023
0.0024
0.0148
0.0158
0.0170
0.0184
0.0200
0.0104
0.0112
0.01.18
0.0128
0.0140
0.o1.1.1
0.0124
0.0145
0.0169
0.0184
0.0204
0.0076
0.0085
0.0101
0.0116
0.0127
0.0140
0.0054
0.0059
0.0071
0.0082
0.0089
0.0097
0.0027
0.0030
0.0036
0.0041
0.0044
0.0048
0.0222
0.0248
0.0290
0.0338
0.0368
0.0408
0.0152
0.0170
0.0202
0.0232
0.0254
0.0280
11
10
9
8
7
6
5
41./2
4
1/
_.
Minor dianAer tolerance for internal thread is one-tenth of the
minimumminor diameter.
70
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●
I
FED-SIH128/2B
.. .; -T-,
CIVIL AmtcY
CustxMians:
GA-7FXE
Eur-Accl
NMiA-JFK
“~v+&
Air Force - 99
PREPARINGPLTMTY :
Review Activities:
Amly-cR,
E?i, ER, ME
Air Force - 11, 15, 82
ccoFu31rwrIm AcrlvITm:
D.I A-Is
(DcDProject‘I131X3-0082)
User Activities:
o
1.
Army -AT, MI
r
I
●
71
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SIANDARDIZATION
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S. DATE OF SUEIMl~lON
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Cl 0080
L@TE.
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flnddr
(YYMMDD)