ANSI B7.1-2010
Explanatory Information
6 Mounting
(NOT PART OF ANSI STANDARD)
6.1 Inspection
E 6.1 Inspection
Prior to mounting, all wheels shall be inspected
for damage and cracks.
Defective grinding wheels are unsafe and must
not be mounted. A damaged or cracked wheel
might disintegrate while in operation which
could result in personal injury.
Wheels which show any evidence of cracks,
abusive handling or abusive storage shall not
be mounted.
If any evidence of cracks or other damage is
found, the wheel should be destroyed or the
information should be reported to the manufacturer and arrangements made for inspection.
6.1.1 Inspection methods
E 6.1.1 Inspection methods
The user shall visually inspect each abrasive
wheel and should apply an additional crack detection test when a suitable test is available.
Defects such as broken wheels, chips, and
gouges can be detected visually.
6.1.1.1 Visual inspection
All wheels shall be carefully inspected visually to make sure that they have not been
damaged in transit, handling, storage or from
other causes.
Cracks in abrasive wheels are frequently not
visible to the naked eye. Effective test methods
have been developed to detect cracks which
are not detected by visual inspection. Two of
these methods are the ring test and the vibration test.
6.1.1.2 Ring test
E 6.1.1.2 Ring test
The ring test depends on the damping characteristics of a cracked wheel to alter the sound
emitted when the wheel is tapped lightly. It is
subject to interpretation by the inspector and is
primarily applicable to vitrified bonded wheels.
To perform the ring test, wheels should be
tapped gently with a light nonmetallic implement, such as the handle of a screw driver for
light wheels, or a wooden mallet for heavier
wheels.
If the wheel is not too heavy, it may be suspended from the hole on a small pin or finger.
(See illustration 69.) Heavier wheels may be
allowed to rest in a vertical position on a clean
hard floor.
Tap wheels about 45° each side of the vertical
center line and about 1″ or 2″ from the periphery
as indicated by the spots in figures 44 and 45.
Rotate the wheel 45° and repeat the test.
Illustration 69
87
ANSI B7.1-2010
Tap the wheel gently with a nonmetallic implement such as a wooden screw driver handle
for light wheels and a wooden mallet for heavy
wheels. The best spot to tap a wheel for the
ring test is about 45 degrees either side of the
vertical center line and about 1 or 2″ from the
periphery. (See figures 44 and 45.)
Figure 44
Figure 45
Large, thick wheels may be given the ring test
by striking the wheel on the periphery rather
than the side of the wheel.
A sound and undamaged wheel will give a clear
tone. If cracked, there will be a dead sound
and not a clear ring and the wheel shall not
be used.
Limitation: Wheels must be dry and free of sawdust when
applying the ring test, otherwise the sound may
be deadened.
The ring test is not applicable to certain wheels
because of their shape or size.
Examples are:
1. small wheels (4″ diameter and smaller);
2. plugs and cones;
3. mounted wheels;
4. segments;
5. plate-mounted wheels;
6. inser ted nut and projecting stud disc
wheels.
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If struck directly along the vertical center line,
the ring, even in a sound wheel, is sometimes
muffled and may give the erroneous impression
that the wheel is cracked. This is especially
true with large wheels which are supported on
the floor when conducting this test. (See figure
45.) Also, it is sometimes noticeable when the
wheel is suspended from the hole. It is recommended that the test be repeated after rotating
the wheel 45 degrees to the right or left.
Apply this ring test immediately before mounting either a new or used wheel on a machine.
Comparison of the sound with other wheels
of the same lot and specification will allow
rejection of any wheel with a suspiciously different ring.
ANSI B7.1-2010
6.1.1.3 Vibration test
E 6.1.1.3 Vibration test
The vibration test is based on the way that loose
sand or similar material is distributed on the
side of a wheel when the wheel is vibrating.
The vibration test can be used either in lieu of
or in conjunction with the ring test. The test is
applicable to all bond types and is not impaired
by ambient noise.
To perform the vibration test, an abrasive
wheel is set on a test fixture in the horizontal
position and coated with a thin layer of fine,
dry sand. The wheel is vibrated gently. As the
wheel vibrates, the sand granules respond to
the vibration energy. If the wheel is cracked,
the granules move away from the crack; if the
wheel is sound, the granules will continue to
be uniformly distributed over the entire surface
of the wheel.
Perform the vibration test before mounting either
a new or used wheel on a machine.
The test should be conducted on both sides
of the wheel.
6.1.2 Metal centered wheels
Steel center abrasive cutting-off and diamond
cutting-off wheels with cracks in the metal center
shall not be used.
6.2 Spindle speed
E 6.2 Spindle speed
It shall be determined at time of mounting that
spindle speed does not exceed the maximum
operating speed marked on the wheel or wheel
package. Spindle speed shall be measured
at free running speed of the machine. When
a partly used wheel is remounted, spindle
speed in revolutions per minute may exceed
the maximum revolutions per minute marked
on the wheel provided the maximum peripheral
speed (surface feet per minute), established
for the wheel when new, is not exceeded. (See
sections 1.2.72, page  8, 1.2.88, page 10, and
1.2.97, page  11, for explanations and calculation of peripheral speed from revolutions per
minute. Also, wheel speed conversion table on
page 10 may be helpful.)
Illustration 70 – Free running speed of
spindle being measured with a tachometer
89
ANSI B7.1-2010
6.2.1 Tension speed
E 6.2.1 Tension speed
It shall be determined at time of mounting a
steel centered diamond cutting-off wheel that
spindle speed is within +10%/-20% of the tensioned speed marked on the wheel.
If the cutting-off wheel is operated at a speed
substantially different from the speed it was
tensioned for, it will not run true, i.e., it may
wobble or flutter. Therefore, the user must operate within the recommended speed range.
Failure to do so could cause damage to or
failure of the wheel's steel center, leading to
serious personal injury.
6.3 Arbor hole size
E 6.3 Arbor hole size
Abrasive wheels shall fit freely on the spindle
and maintain proper clearance under all grinding conditions.
The machine spindle or adaptor size must be
maintained by the user. Worn or undersize spindles or adaptors can cause an out-of-balance
condition, contributing to wheel failure.
A controlled clearance between the wheel arbor
hole and the machine spindle (or wheel sleeve
or adaptor) is essential to avoid excessive
pressure from mounting and spindle expansion.
Therefore, wheel arbor hole size equal to or
exceeding the dimension shown in table  22,
page 92, and spindle dimensions shall meet
requirements of section 3.3, page  32.
Tolerance for the arbor hole for steel-centered diamond cutting-off wheels should be
+.002/–.000″ to the minimum size given in
table 22, page 92.
6.4 Surface condition
E 6.4 Surface condition
All surfaces between the wheel, blotters and
flanges that come in contact with each other
during mounting shall be flat and free of foreign particles.
Flanges can be distorted by excessive tightening
or burred by dropping and must be inspected
each time a wheel is mounted. (See section 5.8,
page 80.) Inspection for foreign particles should
be made on wheels, blotters and flanges.
Presence of foreign particles in these areas can
result in uneven mounting pressure against the
sides of the wheel causing stresses that can
lead to wheel failure.
6.5 Reducing bushings
E 6.5 Reducing bushings
Reducing bushings shall be specifically designed, properly manufactured and fitted when
used in abrasive wheels. The bushing shall
fit freely on the spindle and maintain proper
clearance under all conditions. Minimum machine spindle size as shown in table  1, page
34, should not be violated. Reducing bushings
shall not be used to mount a larger abrasive
wheel on a grinder than those for which the
grinder was designed.
If a reducing bushing is wider than the wheel
in which it is used, it will interfere with proper
tightening of the flanges against the wheel.
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The power required to drive a grinding wheel is
transferred through the flanges. If this power is
partially or completely transferred through the
reducing bushing, wheel failure may result.
ANSI B7.1-2010
When a reducing bushing is used in the wheel
arbor hole, it shall not exceed the width of the
wheel and shall not contact the flanges. Loose
reducing bushings (not mechanically held)
should not be used with wheels less than 1/8″
in thickness.
Only an appropriate reducing bushing may be
used to compensate for an oversize arbor hole,
and substitutes, such as flat shim stock, must
not be used.
Separate reducing bushings, unless supplied
or recommended by the abrasive wheel manufacturer, shall not be used to adapt larger hole
abrasive wheels to portable, hand held tools.
6.6 Blotters
See section 5.6, page 78.
6.7 Flanges
See section 5.1, page 72.
6.7.1 Uniformity of diameter
See section 5.4, page 77.
6.8 T i g h te n i n g o f m o u n t i n g n u t a n d
screws
6.8.1 Single end nut
E 6.8.1 Single end nut
The spindle end nut shall be tightened only
enough to drive the wheel and prevent slippage.
Overtightening of the spindle end nut may
spring the flange. A sprung flange can cause
stress concentrations which may break the
wheel. Under-tightening of the spindle end nut
can permit wheel slippage which may result in
breakage.
The means and procedure recommended by
the machine building for tightening the spindle
end nut should always be followed.
Illustration 71 – The above clearly illustrates the
results encountered when the spindle end nut is
excessively tightened
91
92
3/8″
1/2″
3/4″
7/8″
1″
1 1/4″
1 1/2″
1 3/4″
2″
+.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001
5/8″
2 1/2″
+.004
3 3/8″
3 1/2″
4″
+.002
5″
+.006
6″
DIAMOND and CBN
+.001
+.001 +.001
TOOL GRINDING
+.002
+.001 +.002
+.002
+.002 +.002 +.002 +.003 +.003 +.004
14″
16″
24″
+.005 +.005
+.005
20″
+.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001
+.001
+.001 +.001 +.001 +.001
SURFACE GRINDING
Horizontal
+.001 +.001 +.001
+.010
+.004 +.004 +.004 +.006 +.006 +.006 +.007
+.010
+.006 +.006 +.006 +.007
+.003 +.003 +.004
SNAGGING
Swing Frame
+.004
12″
+.010
+.001 +.001 +.001 +.001 +.001 +.001
+.001
+.001
+.001 +.002
10″
+.003 +.003 +.004
8″
SNAGGING
Mechanical
SNAGGING
Portable
SNAGGING
Floor Stand (Organic)
+.001 +.001 +.001 +.001
+.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001
SAW GUMMING
SNAGGING
Floor Stand (VIT)
+.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001 +.001
OFF HAND
INTERNAL
+.002
+.002
3″
+.002 +.002
2 3/8″
CYLINDRICAL
Centerless Regulating
+.001 +.001 +.001 +.001 +.001 +.001
1/4″
+.002
+.001
3/16″ &
Under
NOMINAL ARBOR HOLE DIAMETER
CYLINDRICAL
Centerless
CYLINDRICAL
Between Centers
CUTTING-OFF
WHEEL END USE
Table 22 – Minimum arbor hole sizes in inches ANSI B7.1-2010
ANSI B7.1-2010
6.8.2 Multiple screws
E 6.8.2 Multiple screws
Multiple screw flanges shall be tightened uniformly to prevent springing of the flanges and
to ensure even distribution of mounting pressure over entire surface of the flanges. Flange
screws shall be tightened in a crisscross sequence similar to that illustrated in figure 46.
Figure 46 illustrates only 6 and 8 screw flanges
but a similar sequence can be devised for any
number of screws.
The gradual tightening of screws on multiple
screw type flanges by use of a torque wrench
is recommended. The tightening should proceed
from one screw to one diametrically opposite
and then in a crisscross manner until sufficient
pressure is applied uniformly to prevent slippage. Care must be taken to avoid excessive
tightening as it may cause springing of the
flanges resulting in wheel breakage. Excessive
tightening is particularly dangerous if flange
screws are tightened when the wheel mount
is at operating temperature and then allowed
to cool. Spindle contraction during cooling
may increase flange pressure. If the resulting
pressure is excessive, it will spring the flange
resulting in stresses which may break the
wheel. The use of impact wrenches to tighten
the flange screws on sleeve adaptor flanges is
not recommended. This method will cause the
first screw to have excessive torque and then
every remaining screw likewise. It is an unsafe
method to tighten multiple screws.
Torque wrenches should be used to tighten
screws on multiple screw flanges. Applied
torque should not exceed 20 foot pounds unless greater torque is recommend or approved
by the machine builder.
Screws shall be clean and free running. Screws
shall be of such length as to ensure proper
clamping of the wheel by the flanges.
1
6
3
4
5
2
Order of Tightening
1-2-3-4-5-6
1
5
8
3
4
7
2
6
Order of Tightening
1-2-3-4-5-6-7-8
Figure 46 – Sequence of tightening
screws on multiple screw flanges
6.9 Direction and length of thread on machine spindle
See sections 3.3.4 and 3.4.1, page 33.
Maximum permissible applied torque is dependent on flange design and material. Since
flange properties are determined by the machine
builder, his recommendations as to maximum
applied torque must be followed. Applied torque
of 15 to 20 foot pounds is common with single
wheel mounting, however, some exceptionally
severe operations require greater torque.
Screws must be free of foreign material and
threads of screws and tapped holes must be in
good condition. Otherwise, equal torque applied
on all screws will not provide uniform clamping force. If clean screws are not free running,
they must be replaced and/or holes retapped
to provide adequate threads.
If flange screws are too long, they may bottom
in tapped holes resulting in a loosely clamped
wheel. If screws are too long, they must be
replaced with screws of correct length.
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ANSI B7.1-2010
6.10 Threaded hole wheels
E 6.10 Threaded hole wheels
Special consideration must be given to threaded
hole wheels of the following types: 6, 11, 16,
17, 18, 18R and 19.
When threaded hole wheels are used, as in
cups, cones and plugs, the size and mass of
threaded hole wheels must be kept within limits
which have been found safe by experience for
this mounting procedure.
The direction of the thread shall be such that
to remove the wheel it must be turned in the
same direction it rotates when in use.
The length of the spindle shall be such that
it shall not bottom in blind threaded hole type
wheels.
With this type of mounting, a relieved back
flange must not be used. If made with a relief,
it can pull the busing out of the wheel. See
illustration 72.
Spacers shall not be used between threaded
hole wheels and back flanges.
Threaded hole wheel mounting should not be
used with wheels larger than 6″ diameter.
Threads in threaded hole wheels should be of
class 2B and should be relieved on the side
fitting against the flange so as to allow the
wheel to be screwed firmly and flat against
the back flange.
Illustration 72 – Mounting of threaded hole wheels
6.11 Mounting of abrasive discs (inserted
nut, inserted washer and projecting
stud type)
E 6.11 Mounting of abrasive discs (inserted
nut, inserted washer and projecting
stud type)
Machine face plate (steel disc wheel) and
mounting surface of the wheel shall be flat and
free of foreign particles.
For other requirements for mounting abrasive
discs see section 3.9, page 39.
6.12 Mounting of plate mounted type
wheels
Machine face plate (steel disc wheel) and
mounting surface of the wheel shall be flat and
free of foreign particles.
For other requirements for mounting plate
mounted t ype wheels see section 3.10,
page  41.
94
Illustration 73 – An inserted nut type
abrasive disc showing proper mounting
ANSI B7.1-2010
6.13 Safety guards
E 6.13 Safety guards
At the completion of wheel mounting and prior
to starting the wheel, the safety guard shall
be secured in place. The safety guard shall
be inspected for condition and adjustment. All
safety guard fasteners shall be in place and
properly tightened. (See section 4.1, page 50,
for full information and exception.)
Illustration 74 – A band-type guard used with Type
11 cup wheel
6.14 Mounted wheels
E 6.14 Mounted wheels
Machine speed shall be set and measured
to make certain that it does not exceed the
maximum operating speed for the mounted
wheel as used.
Since the overhang “O” of the mandrel of a
mounted wheel is a factor in determining the
maximum allowable operating speed, care
should be taken to assure that the overhang
conforms to the limitations shown in section  10,
page 117.
(See table 23, page 99 and tables 26 through 34,
pages 121-131, for explanation.)
6.14.1 Mounted wheels on portable air
grinders
The wheel mandrel shall be inserted to the full
depth of the gripping jaws of the grinder collet.
(See section 10, page 117.)
Illustration 75 – Dimension “O” indicates overhang
of the mandrel
95
ANSI B7.1-2010
6.15 Types 27, 28 and 29 wheels
E 6.15 Types 27, 28 and 29 wheels
Types 27, 28 and 29 wheels shall be mounted
with adaptors or flanges as specified in sections 5.1.2.2 and 5.1.2.3. The specially designed
adaptors described in section 5.1.2.2 shall be
used to mount only Types 27, 28 and 29 reinforced organic bonded wheels.
Types 27, 28 and 29 wheels are designed for use
on right angle head or vertical spindle portable
grinders. Type 27 wheels with flat outer area
are suited for notching and cutting operations
as well as flat area grinding. Type 28 wheels
with a saucer-shaped outer area are suited for
corner cleaning work and must not be used for
notching and cutting operations. The variance
in diameter between the back flange and the
adaptor nut and use of side pressure in wheel
operation limit the use of this mounting to reinforced organic bonded wheels.
Flanges and adaptors shall be checked for
flatness of bearing surface. Sprung or warped
flanges or adaptors shall not be used.
Mounts which are affixed to the wheel by its
manufacturer shall not be reused.
At the completion of mounting, a safety guard
shall be in place between the wheel and the
operator position. (See section 4.2.2.3 and
figure 13, page 53.)
6.16 Type 27A wheels
It is important when mounting Types 27, 28 and
29 wheels that proper contact is made between
the wheel and the back flange.
Flanges must be checked for flatness since a
warped or sprung flange will cause vibration
and possible wheel failure.
See section 5.1.2.1, page 74.
When these wheels are supplied with a throwaway type mount attached by the manufacturer,
the mount must not be reused.
6.17 Type 2 cylinder wheels
E 6.17 Type 2 cylinder wheels
Type 2 cylinder wheels have diameter, wheel
thickness and rim thickness dimensions. Grinding is performed on the rim surface. The wheel
is chucked or cemented directly to the machine
face plate which is securely attached to the machine spindle. The machine face plate shall be
flat, concentric and at a 90° angle as mounted
to the machine spindle. Cylinder wheels shall be
used only on machines equipped with band type
safety guards that conform to general specifications outlined in section 4.3.14, page 66.
Minimum thickness of machine face plate is the
same as that shown for disc wheels in table
2, page 39.
Illustration 76 – Examples of Type 2 cylinder wheels
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ANSI B7.1-2010
6.18 Segments
E 6.18 Segments
Segments individually chucked in suitable holding mechanisms to form a grinding unit shall
be mounted in a manner prescribed by the
manufacturer of the chucking device. The safety
guard should conform to that used for cylinder
wheels. (See section 6.17 and specifications
outlined in section 4.3.14, page 66.)
Some shapes are designed to be chucked
at one end for the entire segment life. These
tend to flare outward due to centrifugal force if
improperly mounted. To prevent this, it is recommended that two retaining bands be used
with these segments during operations. As the
segments wear, each band should be removed
to avoid interference with the work.
Newly mounted segments used in chucks which
are not designed to downfeed through the
chucking device should be securely mounted
with two equally spaced retaining bands. See
illustration 78.
Illustration 77 – A segmental wheel assembly
Illustration 78
97