OREGON FOREST PRODUCTS
LiBRARY
LAIIr4 LALiIJS CF USCCLCIfL
i
AII2CIAFi VFFLI2S
wcu
Novcmbcr 1944
)Qt41fl
ThIS
L?FIDOF?T IS
ONE 0E A SUiES
ISSIJEt
WAL? I)L?OGL?AM
TO AIE
¡I-lE
ForQst
IDithoIoy SpQdaI LcIeusc No. 22
NATION'S
.
UNITED STATES DEPARTMENT OF AGRICULTURE
AGRICULTURAL RESEARCH ADMINISTRATION
BUREAU OF PLANT INDUSTRY.
SOILS, AND AGRICULTURAL ENGINEERING
DIVISION OF FOREST PAThOLOGY
MADLSON, WISCONSIN
IN COOPERATION WITH THE
FOREST PRODUCTS LABORATORY
FOREST SERVICE
.
LAR
,-._
--
B:EAIcnTa PAD lUS OF DISCOLOPD
Py
THEODORE C.
WOOD flT
SCH'FER,
ans. CATHERINE G. DUNCAN,
AIRCRAFT VEIEERS
Patho1ogit
Patho1oist
Division of Forest Patho1oy1
Bureau of Plant Industry, Soils, and. Agricultural
Engineering
Agricultural Research Administrat ion
United. States Department of Agriculture
Sutnmary
:e IDreaking radii of
hardwood.
cate that
.
s:ecìes
riously discolored veneers of six different
were small enough, for most of the discolorations, to indimich veneers can be used- successfully on members
having curved sur-
faces. rnen expressed in terms of the
radius of curvature attained
without fracturing, the ìreaking radius minimum
in
nearly
cases was small enough
to be aomly covered by a ninimum factor of safety all
of
3,
as suggested in ARC-19,
Wood. Aircroît Inspection and.
Fabrication.
The only definite exception was
veneer discolored by decay fungi. Some uncertainty as to
sharply curved surfaces was indicated, however, for mineralsuitaMlity for
in yellow
birch, for the dark reddish-purele variety of mineral stain streaks
in yellow-poplar,
and. for gum streaks in mahogany and.
khaya.
Introduction
?he
principal discolorations of yellow-poplar, sweetgui4, yellow biroh,
lIn cooperation with the Forest Products Laboratory,
Service, United
maintained. by the
States Department of Agriculture, at Madison, Wis., Forest
in
cooperation with the University of Wicconsin.
-?Credit is due Francos N. Lombard. for oubstantial
assistance in preparing a
portion of the test material. Tue veneer was collected.
and the toughness
tests were made by the authors of articles cited in footnotes
3-7.
Hepting, George H., Roth, Elmer R., and Luxford., R. F.
The significance of
the discolorations in aircraft veneers:
yellow-poplar.
Forest Prod. Lab.
i4imeo. 1375. 8 pp., il1s. Nov. 1942.
.Scheffer, Theodore O., arid Hansbrough, John R. The significance of
the discolorations in aircraft veneers: sweetgurn. Forest Prod. Lab. Mimea.
1376.
B pp.,
illus. Oct. 1942.
j. R., Waterman, A. II., andLuxford., R. F. The significance of
the discolorations in aircraft veneers:
iirnoo. 1377. 7 pp., illus. Jan. 1943, yellow birch. Forest Prod. Lab.
Hansbrough,
Por. Path, Spec. Release No. 22.
-1-
OREGON FOREST PRODUCTS
LIBRARY
mahoany.9-, khaya, and. American beech2. have reont1y been claBsifle6- and- dOescribed. The utility of the discolored veneer for aircraft as evaluated from
tougbness tests, was discussed in the same reports. With the exception of the
gum streaks and the brown streaks in mahogany zd khaya, all of the discolora
tion not associated with decay listed in this report were previously determined
to be accetab1e from the standpoint of tougbnoss.
The present report gives the
results of bending tests made to ascertain which of the discolorations may cause
veneer to have such a large breaking radius as to present objectionable dif
ficulty in the inanufact-ure of curved parts of aircraft.
,'
Test Methods
The breaking radius of the veieer was deternined on a step-type series of
constructed of wood and designed at the Forest Products Laboratory
for determining the relationship of radii of curvature at breakage to elope of
grain through sheets of veneer. The radii of curvature of the mandrols ranged
from 3.50 to 0,125 inches, in steps of 0.25 inch between 0.75 and 3.50 inches,
and of 0,125 inch between 0.125 and 0,75 inch.
rnandrels,
In testing, specimens of veneer, 2-1/2 to E inches long in the direction
of the grain and 1/2 to i inch wide, were bent around mandrels of decreasing
radius until definite evidence of fracture was obtained.
The radius of curvature last preceding the one causing fracture was recorded as the breaking radius.
This radius was determined usually for 2 portions of each specimen and the
results were avoraged. The bending was done with the fiber direction at an
angle of 90° to the axis of curvature, and with.the "tightt side of the veneer
toward th mandrel. To insure a reasonably accurate evaluation of the breaking
radius, the veneer was pressed as firmly againt the mandrel as possible over
the entire length of the bend, which usually was not greater than about l-1/2
inches, Each test, moreover, was started. on a radius of curvature several steps
larger than the breaking radius, This was done in order that all of the specimens might be subjected tri about the carne amount of flexing preceding fracturing,
Specimens for the tests were taken from etraight-grained areas on the
veneer sheets and as nearly parallel with the grain as cöuld 'ne determined by
eye.
In t1e majority of determinations each individual test was represented
by at least two specimens, one being taken foni the discolored area and the
other, serving as a control, being taken from an adjacent area of clear, sound
wood. To get both specimens as nearly as possible from the saine growth rings
of the wood, the control was taken from wood extending frrim the end of the discolored specimen in quarter-sliced veneer or from wood. either at the end or
side of the discolored specimen in rotary-cut veneer. Tacts of this sort are
Hansbrough, J. R. and Krause,R.L. The significance of the discolorations in
aircraft, voneers:
mahogany and. khaya. Forest Prod, Lab. Mirneo, 1379. 7 i?P.
,
illus,
Nov, 1943.
.ZHansbrough, J, R, Waterman, A. M,,, and Krause, R. L.
discolorations in aircraft veneers: American beech,
Release o, 16, 6 pp. illue, April 1944.
For. Path. Spec, Release No, 22
-2-
The significance of the
Forest Path, Spec.
commonly known as matched tests, and are particularly useful in that differences
obtained between the sound and discolored wood. ascribable to factors other than
those related to the discoloration itself are reduced to a minimum.
With rotarycut veneer, the discolored and control specimens
could
not
be SO
9ömetimes
closely matched, because of the way in which the discoloration was distributed.
Clear veneer anywhere in the same sheet then had. to be used for the controls.
Supplementary tests showed that the reliability of tests was riot consequentially
reduced by matching of this kind.
In fact, it is necessary to have some such
matching in order to sample centers as well as the margins of discoloration zones.
With sorne of the material, discolored, and adjacent clear wood was included
in the same test specimen.
This was done to find whether any consequential weakness existed along the line of juncture.
Prior to and during the testing, the specimens were held at a relative
humidity of 30 percent and. a temperature of 800 P. This resulted in an equilibrium moisture content of the wood of approximately 6 percent.
Results
and.
Conclusions
The mandrel-bending results shown in tables 1 through 6 are summarized. in
tbree ways:
(1) as the actual 'breaking radii of both normal and discolored
veneer of irarious thicknesses, (2) as ratios of the breaking radius to veneer
thickness, and (3) as ratios of the breakiig radius of the discolored veneer
to that of the matched normal
on any of these difComparisons can
ferent bases, as desired. However, the results expressed in terms of the ratio:
discolored veneer
9
may be evalulated. without regard to veneer thickness-,
and
normal Veneer
it is from this ratio that the conclusions were largely derived.
In interpreting
such a ratio it should be kept in mind that since increase in the breaking radius
meant decreased bending capacity, lowered bending capacity is indicated 'by ratios
greater than 1.
.
.
Measured by these ratios, the 'breaking radius of veneer containing most of
the different types of discolorations was somewhat larger in general than that
of veneer of normal color, but because of the comparatively large factor of
The breaking-radius ratioswere averaged geometrically.
The geometric average
th root of the product of
is the
n values.
With the present data the
geometric averages are, for the most part, not much different from those obtamed 'by ordinary arithmetic averaging. They were used because they give
discolored
normal
normal
is the reciprocal of the geometric average o± the values
which
discolored
is not true for the arithmetic average.
Althcugh the minimum breaking radius increases markedly with increases in thickconsistent relative values,
ness of veneer, the ratio
The geometric average of the values
radius item
breaking radius control
if at all, related to veneer thickness,
Por, Path. Spec, Release No. 22
-3-
apparently was
'but
slightly,
safety
generally used in bending, the increase was not enough to be of concern in the fabrication of curved aircraft surfaces. For a few of the
discolorations, however, the averare breaking radius was enough larger than that
of the normal veneer to suggest an
objectionably low bending capacity.
Discolored veneer with a breaking radius represented by a ratio greater
than 3.00 would fracture if bent to the degree permitted by a factor of
safety
of 3 for the associated normal veneer.
If the normal veneer itself were in the
low range of bending capacities for material meeting Specification
AN-NN-P-511b,
a ratio
presumably could be substantìally less than 3.00 and the veneer still
fracture on the radii of curvature prescribed by a factor of safety of 3 applied
to the breaking radii indicated by figure 5-90 of ANC-19. Since the
normal
veneer used in the present tests was of about average aircraft quality, it is
not possible to define precisely what ratios would be indicative of
excessively
reduced bending capacity if the discoloration were in veneer cf otherwise low
capacity.
It is regarded as conservative, however, to assume that with discolorations that in these tests gave ratios of 2.00 or higher, there is likely
to be an objectionable proportion of material of inadequate bending capacity.
Although none of the ratios exceeded. 2.00 on the average, they d-id in
many individual tests, With the decayed birch and. beech veneer, 58 and 45
percent, resuectively, of the ratios were greater than 2.00, and 15 and 11
percent
of the respective ratios were as great as
3.00.
Slight decay may not increase
the breaking radius to this extent; it did not in the
sweetgum and yellow-poplar
samples. Nevertheless, veneer with incipient decay should not be used since there
is always the possibility that the
bending capacity may be severely reduced.
Of much greater importance is the critical
weakening caused by decay.
Of the discolorations not associated with decay, only the dark
reddishpurple mineral stains in yellow-poplar, mineral streaks in yellow birch, and
gum streaks in mahogany and khaya had a bending capacity seemingly inadequate
for the more severe aircraft curvatures. Aproximately
1 percent of the ratios
for each of these discolorations
except for the gum streaks in khaya.21, exceeded 2.00. Gum streaks, because of their general lack of strength, might
well
be restricted on a basis such as is applied to splits
and open joints. The
other two cliscolorations might be restricted to
flat-panel construction or
moderate curvatures insofar as is practicable.
There wa no marked tendency for the veneer to split along the margin of
normal and discolored wood. as a result of bending.
It is suggested in ATC-l9, Wood
.ircraft Fabrication and Inspection, that a
minimum factor of safety of 3 be used, in which case the bending radius used
would be at least 3 times as large as the average breaking radius for veneer
of the same kind and condition. For
example, if the average breaking radius
of the specified veneer is 2
inches, a minimum working radius of 3 times 2,
or G IflCilGS, is suggested.
iGum streaks were found in supplementary observations to be quite brittle for
the most part, and it is probable that their true bending
deficiency was not
developed in the lthaya tests because of the large proportion of streaks that
were so narrow as to involve only part of the width of the test specimen.
For. Path4 Spec. Release
ITo,
22
-4-
Table
1.
---Breaking radiue of normal end diecoored 8weetUm1
-
--
Average ratio:
:Veneer:Number :Medlan breek1ng:Rtio of medien breakNormal
to
:ing
radius
radius
of
thiCese:Bre
:thickradius,'Çreakin radi
wood
of control
neas :watched: of item -'
used as
Control
Item
Item :Control:
testg
control
:
:
Item tested
:
:
:
:
:
:
:
:
:Inee:
:
:
Decay (varioe ehados of doll brown). :Heartwood:O.023
:eartwood: .035
.066
:Sapwooi
.086
:Sapwood
:1.11 testa:
:
:
:
10
g
:
16
:
:
;
Mineral streak
.022
Broad; rt-bron color ............ $apood
.066
Do .............................. Sap,od
Do ............................. :Eeartwood: .066
:
:
POOd
Ìarrov; reddie'-bon color .......
Do ............................ :Sapwocd
Do, ............................ :Sapwood
Heartwood streak ..................... ;Se.pwood
:
:
21
:
0.38
:
.60
:
.87
2.56
:
1.93
2.20
:
:
:
37
12
:
.031:
:
9
:
:
:
:
;
.3g
:
l.21.
:
1.52
:
.2Z
.
:
.5
.61
.7'4.:
.51.
13
:
1.0
i.g
:
:
.39
:
121
:
16
:
.714
:
.72
16.5
17.1
29.2
25.6
:
:
:
25.6
29)4
:
1,314
¡
1.32
:
1.65
1.91
1.11
:
:
:
l.25*
:
21.5
2g.O
;
1.20
:
:
1.15e'
:
:
:
ig.a
19.7
25.k
12.7
22.9
23.9
11.7
23.9
17.3
:
:
1$.
:
¡
23.0
:
1.13
1.07
1.10
12.1
:
i.o6
25.
:
:
16.14
:
:
i6.g
23.2
;
20.3
:
20.0
.93
1,25
1.12
:
:
Highly significant. Lese than i cnance in 100 of accidental occurrence.
Vlue not footnoted are no statisttca.ly significant.
F
:
:
:
.1O
Gecmetric average of ratios for the individual matched tests.
Z?6
:
2$.7
33.k
32.1
32.3
:
;
:
:
2.kk
:
Ahout 75 percent was rotary-cut material; remainder was quarter sliced.
Z M
:
.75
;
:
:
:
29
:
;
.066
0.66
1.17
2,12
2.7e
:
7
.024
:
Inches:
:
J
:
.022
or gra'-brown color....:Sapwood
Gt'eonish
.031
Do ............................. Sapwood
:A11 tests:
:
lachee:
io
;
O3
.037
:Sapwood
A11 teets:
;
:
:
:
:fl,tod;
Sap (blue) etain ......................
:
:
:
:
:
1,08e.
1.01
Tablí
-
.-rakin
radtu of noraal and d1co1ored
oraa1
:
Ttan testad
used au
:
control
no
:
to dar-bro,n color
breaking: Ratio of median breakAyera «e ratio
radine
:in radtn to
.._.Break1ng radtue,éBreang radlu
matched: --- te8tu ttin :Control: Ttaa
of
of control
Control
:
:
12
:
b
:
SapwOOd ande
heartwood
:!eartwood
color over1rtnr black
adneral itMn
.0I4
?A11
"!naral stain (inc1udtn bine bott)
an minra1 tra
'ark r,iih-nnrc1e color .........
.050
tet
:
:
:
1.79
2.99
:
:
J
116
:
1.70
:
0.93
:
:
24.l
1.59
2.70
22.7
:
:
:
:
:
:
35.
:
35.6
reanth-brown color .....
:
1.52
:
.052
:
1.1S
103
.95
.05
Taartwood
:
:
t*t
:
:
rethHah-ourole color ......... ;SOod and;
!A11
:
:
tst
.6
:
ig.
2.0e
:
:
i.o6
1
:
27.9
32.0
1.09
1.09
:
1.13**
:
:
24.6
34)4
23.7
30.2
:
i.06
;
1.13**
:
tests
:
:
:
:
:
:
:
:
Sapwood
:
:Allteste
:
:
:
:
:
;
:
:
:
:
:
:
:
:
:
:
23
31
19
:
:
:
:
:
1.21
1.20
2.62
:
:
1.08
1.06
1.5k
2.k9
:
:
:
:
:
:
1.12
1.56
2.29
:
:
:
;
:
23.7
22.5
:
sapwood
:Sapwood
:
:Sawood
:
043
:
:
.04$
.056
.062
27.9
:
27.7
11
;
:
12
:
:
$2
:
:
1.05
:
:
25.3
23.3
:
:
19.0
30.1
:
25.1
:
2.k
:
28.6
:
:
21.k
23.5
25.7
26.3
:
:
:
1.05
1.13
:
2Q.4
1.03
:
19.3
22.0
23.6
28.3
1.1
1.10
1.0$
¡
:
:
:
1.09**
:
10
:
1.09
:
TI
stain ......................
:
:
:
.3
:
:
26.k
:
:
:
.92
1.20
1.70
2.29
214.5
:
:
1.09
19.1
:
:
1.4+
:
:
:
:
:
:
.051
.066
.081
:
:
1.145
28
30
21
10
22.5
:
1.40
.97
:
:
:
:
1.02
6
:
.th3
1.30
:
j
:
:
:
:
:
orma1 heartwood ..................... :Sapwood
:Sapwood
:Sapwood
j
39
:
:
.82
.97
:
:
Lavender color .................... :Sapwood. and:
heartwood
.043
:Heartwood : .052
:Eaartwood : .063
:Heartwood.
.087
All teste
:
:
:
:
tests
;
22
:
Black ............................. Sawood and:
eartwood
.O43
:Sapwood and:
lieartwood
.052
.99
.95
1.29
:
:
1.3
:
:
.99
1.06
1.23
1.50
23.0
:
:
:
19$
23.0
23.1
:
:
23.0
22.1
22.0
2k.2
:
.95
.92
1.02
:
:
:
cut.
Geometrtc average of ratios for the individual matched teste.
e
Reasonably significant. Less then 5 chences to 100 of as lar,e a deviation from 1.00 occurrin$
High17 sinhutcant. Less than 1 chance in 100 of accidental occurrence.
Values not footnoted are not statistically significant.
E
1.1
:
24.5
29.7
;
1.02
1.51
1.72
19.5
;
:
:
57956
1.22
:
:
;
;
23.2
:
1.30
1.93
:
J,
keartwood
.043
:Sapwood and:
eartwood
.053
:Sapwood
:A].l teSt,
1)4e
6
Sapwood and;
AU
1.02
36
11
0
;
.0l
.050
22.7
:
33
:
1.15
:
:
21
:
:A11
:
17.4
:
:
:
.01;4
fl
1.11e
:
:
:
heartanod
30.4
:
20.0
:
fl
:
heartwood
eartwood
74.0
:
75
Sanwood and:
A11
Purp1h-brown oobor ..............
0
:
:
tet
heartwood
Sawood and
:
M
1.06
1.1v
32.1
:
:
.&43
h,artwood
?A11
t
1.07
:
31.
:
:
:
apwood and
i11 rotar7
:
anwood and
heartwood
Blue (sap)
0.99
ie /
:
ieartvood
.
p*1
:
3
rown
green to
:
:
.0
:
:
,
:
:
:
beartwood :O.Ol
tbcea:
:
:
apwood and
:
--
Nber :ledian
of
:
ecay
Lit
:
:thick-
wood
:
yelloN-poplar1
Veneer
pre1y
by
accident.
Pable
3.-Brean
rMiu.
bircb
of normal and diecolored ye110
Normai.
:
WOOd
used as
contrai
Iten teeted
:
test8
:
Decay (cream colored to broan
diacolorations) ............... Heartwoo&
:Eeartwood
:Heeztwood
A3.1 tests
streak
Yellow to yellowish-white color. . . Sapwood
Do ............................. Heartwood
;
:O.Okk
.052
;
.060
:
:
:
.032
;
:
.05
;
.052
.07ê
:
Striped zone ......................... ;HeartOOd
:end sapwood: .062
.072
:Heartwood
:
.108
:Heartwood
:
:Allteets
Normal h.artwood ..................... $apwood
:Sapwood
:$epwood
:fll testa
Eeartwood streak ..................... ;$ep,od
:Sapwood
¡Sapwood
¡Ail tests
Light streak. ........................ ;Eeartwood
:Heartwood
¡Ail tests
1.21
61
:
:
13.2
13.1
13.5
:
:
:
li
6
:
3
;
lê2
;
:
;
.87
:
13
:
1.08
1.35
:
j
:158
:
2
16
.76
.9
:
.91
:
1.l
:
:
:
:
.071&
. 62
1.01
1.12
17.«
19.3
28.6
:
;
2.00CC
:
:
:
15.8
¡
1.10
1.23CC
:
:
1.25
1.21
1.51
:
1.19
;
;
16.9
18.1
:
:
:
l7.
:
:
18.2
:
lk.7
15.k
:
:
:
:
:
1.19CC
:
:
;
;
1.10
1.20
2.12
17.2
:
:
;
:
:
:
;
1.19
1.16
2.3?
19.5
:
;
.
:
:
:
20
:
:
:
:
:
;
;
.98
:
.
1.k9
:
:
..3
.0k9
.060
:
;
:
:
2.13
2.00
:
:
:
17.2
:
:
:
:
19.2
16.1
21.9
:
:
:
17.7
16.7
19.6
1.09
.93
:
:
1.070*
. 62
.99
.99
:
:
12. 6
12. 6
16.8
15.1
16.5
l3.k
00
1.06
i.
:
1.03*
23
¡
.0143
l
.052
.062
8
¡
:
.062
.110
181
89
:
.71
.87
1.03
91
¡
.69
.68
.98
16.5
16.0
1.03
16.7
16.6
13.1
15.3
1.08
¡
:
1.05*
:
¡
...a
1.05
2.37
1.10
2.37
¡
¡
¡
17.7
21.5
:
16.9
21.5
1.05
:
:
AI1 rotary cut.
of ratios for the indivithial matched tests.
a deviation from 1.00 occurring purely by accident.
Reasonably significant. Less than 5 chances in 100 of as large
occurrence.
of
accidental
SCHigh].
in
100
Lese thar 1 chance
significant.
not tatisticaily significant,
Talues not footnoted
0eometrtc average
*
ar,
Z
M 5795? F
,
radine
Z Breaking
of control
:
29.1
31.1
25.7
:
:
.55
:
:
:
:l9b
:Allte.ts
.55
:
:
:and sapwood: .062
Sapwood
:
:
:
;
:
:
.63
.81
:
:
:
3
:
:
:and sapwood: .062
:111 tests
Do .............................
:
:
:
:
:
:
:
0.58
:
35
:
Broen to greenish-brown color .....
Do ............................. :Sapwood
Do .............................. Sapwood
Do ............................. Reartwood
:
1.2$
1.62
1.5k
:
Control
:
ration
e
radius
Ofit6
,,'
;
:
:
:
60
9
:
Item
¡Control:
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:
:
:
It
:Br8n
-
:
:
:
Ave
:
:ing radius to thickese:
radius
:
of
:thick-:
nose ;matched -
:Incbes:
z
Mineral
:Veneer:Nber :Mediau breakinRatio of median break-
1.050
Table 1--Break1n raì1us of nornal an1 diecolored merican beech
:
Item tooted
:Verieer:Nimiber :Hediaxz
Normal
usedas
:
:
:
:
Do .............................. Sapwoo&
:A11
:
tests
Sap (blue)
stain ...................... Sapwood
Pink heart ........................... :Heartwood
:1.11
Tau
heart ................ :Heertwood
Brownish-yellow
:B.artwood
:A11 tests
Mineral
strasic
(gray-brown
color).... :Sapwood
1A11
50
:
.0k
:
:
:
:
:
:
:
¡
:
:
:
:
_.3ì
13k
28
29
:
:
:
:
.$3
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1.3
57
32
.25
.73
.60
1.29
¡
¡
.67
1.62
:
:
:
:
.81
:
:
:
:
:
:
15.9
3$.7
32.0
3k.5
:
:
:
:
:
:
:
:
1.62
:
:
19.3
1.3
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:
:
:
1.59
:
:
:
16.8
:
10.0
16.2
1I.5
15.2
:
:
:
:
:
12.2
19.0
11.2
¡
:
10.8
¡
16.14
2J5
:
:
1,91**
17.0
:
1.12**
1.8
:
1.03
16.6
13.3
19.0
.92
:
1.27
:
:
1.01
:
1.02
10.0
17.8
12.2
18.7
.90
1.25
:
:
:
1.01
:
10.9
ik.o
:
.2k
1.07
2.10
:
:
u.k
:
:
17.8
:
:
.27
:
:
:
.2k
.59
;
17.14
:
.80
15.0
:
19.5
:
.73
.25
:
.25
:
108
:
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¡
.0142
:
.$0
:
.k
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:
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:
3k
:
:
2.93
:
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1.76
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kl
13b
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:
0.63
:
¡
:
:
:
:
:
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.085
:
:
1.03
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:
93*
:
9.6
1.09
:
:
.69
:
.70
:
¡
¡
16.7
¡
:
____
:
.99
rotary cut.
Geometrtc average of ratios for the individal isatched tests.
Reasonably significant. Less than 5 chances in 100 of as large a deviation
**Hjghl significant. Less than 1 chance in 100 of accidentai
occurrence.
Values not footnoted are not statistically significant.
*
Z M 57958
F
o1:___
;
:
:
0.67
1.7k
200
:
.055
.og5
:
:
17
:Sapwoodand:
heartwood:
¡Ail tests
:
:
.013
:Heartvoo.
¡Ail tests
36
:
heart ............................ ;Heartwood
:Heartwood
:Heartwood
:
36
:
tests
21
ratio
radis,"Breaking radius
-
Ip.he,: Inches;
:
:
.043
;
:Hsartwood.
:Heartwood
.085
:
Pith flecks ..........................
:
:
:O.O2
.045
.055
Sapwood
:Sapwood
Do .............................. Sapwood
Average
-
:Incbas:
With blue stain
Without b1ie stain
:
-
------
:
Decay
:atched :---------
:
__!:__
-
breakin;Ratio of median break:_r1 eto thiebiase
froa 1.00 occurring purely
by
accident.
ab1' 5.-:rea3c1ng radi
of nornaJ. aiid discolored mahoan.y
Normal
:
wood
:
I tern
tested
:
:
used as
control
;
Gwn
:Veueer:Number :Mediai breakiug:Ratio of median brea]o-
:thjc-;
:
;Ins;
........................... :Heartwood:
Brown streak .......................... Heartwood
End stain ............................. Reartwoo&:
rox streak ......................... :Reartwood.s
Water stain .......................... ;Reartwood;
:Haertwood:
tests:
............................'Eeartwood:
Brown spot ............................ Reartwoo&:
Red streak .......................... :Heartwood:
White ensthge .......................... Hsartwoods
spots
tests
:
:
Iron stain
Mold
of
ness :matched
streak........................... ;Heartwood:O.035
:A11
(Swietenia)1
.O3
.035
:
:
27
:
51
:
s
.0314
35
143
:
0.90
s
:
.89
s
s
.70
s
:
1.06
s
.75
.80
.99
.
314
s
s
38
:
.71
148
:
.80
:
s
z M 57959
F
:
25.7
:
30.6
:
22.6
214.7
:
s
22.6
28.2
;
s
20.0
21.9
25.2
:
21.k
of item
:
20.9
s
1.175*
:
1.11
:
1.07
:
23.0
s
ì.o6
19.1
s
1.03
1.01
21.6
23.6
s
1.02
22.0
s
.99
23.1
s
.98
:
:
.75
s
s
.81
:
22.8
:
23.5
:
214.1
s
.96
26.6
s
27.3
s
.96
.0314
s
27
s
.80
:
.82
.0141
s
16
s
1.09
:
1.12
quarter and flat sliced.
Geowetric average of ratios for the individual matched tests.
55Highly significant. Less than 1 chance in 100 of accidental occurrence.
Valuas not footnoted are not statistically significant.
Mixed
2
:
.83
.67
Control
:
;
.96
.79
:
.035
0.79
:
1.014
29
.037
.0142
Inches; Inches:
i
.035
.036
:
Itesi
:Control:
ratio
,
radiis
of control
,// 3reaking
radis
-
:
Item
37
Aver e
--------------- ---------------------
:
:
:
:lng radius to thickness:
radius
:
¡
Table
6.
--
--Breaking radius of normal and discolored kbaya (African
_____------
Item tested
:
Normal
:
wood
:
used a
:
.
Red
nd
etreak
.
control
:Veneer:Ninber :M.&ian breakin:Ratio of median break-
Ave
ratio
:ing radiusto thickness:
Breakin radiuB/ Breaking radius
ness :matcbM: of item ,,,'
of control
: te8te
Item :Control:
Item
:
Control :
:thick-: of
:
:
stain ............................ :Heartwood: .053
:Heartwood:
tests:
.ø6ê
streak .......................... :Beartwood: .036
Worm
:Heartwood: .055
:Heartwood: .065
:A1l tests:
streak ......................... :Heartwood: .053
Brown
:
:
:
:
:
:
:
30
33
J.
I9
Gum
streak
spot
Brown
tests:
........................... :Heartwoodr
:
r
29
:
rl.].ltests:
:
r
:
31
8
16
:
16
r
22
:
1.03.
l.74
:
:
.92
1.19
1.5k
:
:
1.05
:
:
1.68
:
21.9
19.0
27.2
:
:
:
:
:
:
i.ik
2.37
:
r
.97
1.29
1.62
.95
:
:
r
1.16
2.62
r
:
:
:
25.5
27.1
23.7
19.8
26.2
r
:
.93
2.05
2.87
:
r
:
21.5
27.5
18.3
3k.0
29.5
:
:
26.9
:
:
23.1
:
:
2k.9
:
r
r
21.9
30.5
r
:
r
17.9
3k.2
33.)4
r
:
Z M
96O F
.95
j3
1.01
.98
1.17
1.00
:
.98
:
r
r
97
1.02
1,01
:
r
28.9
20.0
i.06
:
:
:
26.2
21.k
:
:
:
:
1.07
1.12
:
:
:
:
r
r
.97
1.20
:
:
:
2.0k
2.5k
2O.4
;
:
:
:
1.06
:
r
quarter and flat sliced.
Geometric average of ratios for the individual matched tests.
Reasonably significant. Less than 5 chances in 100 of as large a deviation from 1.00 occurring purely by accident.
Values not footnoted are not statistically significant.
Mixed
j
:
:
r
:
31
l.l4
:
r
r
Inches: Inches:
:
:
1$
r
.037
:Heartwood: .056
:
:
:
:A1l
........................... :Heartwood:
:
3
:
.052
:Heartwood: .060
:Heartwood: .086
tests:
:
9
:Heartwood: .0g6
:A3.1
:
radius
;
:Keartwood:O.052
:1.11
:
:Inhe:
;
maìiogany)1
.98
.88
kQI
93