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Subchapter 7. General Industry Safety Orders
Group 3. General Plant Equipment and Special Operations
Article 21. Use, Care, and Protection of Abrasive Wheels

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§3583. Portable Abrasive Wheels.


(a) General requirements. Abrasive wheels shall be used only on machines provided with safety guards as required in Section 3577(b).
(b) A safety guard shall cover the spindle end, nut and flange projections. The safety guard shall be mounted so as to maintain proper alignment with the wheel, and the strength of the fastenings shall exceed the strength of the guard.
Exceptions: (1) Safety guards on all operations where the work provides a suitable measure of protection to the operator may be so constructed that the spindle end, nut and outer flange are exposed. Where the nature of the work is such as to entirely cover the side of the wheel, the side covers of the guard may be omitted. (2) The spindle end, nut, and outer flange may be exposed on portable machines designed for, and used with, Types 6, 11, 27, and 28 abrasive wheels, cutting-off wheels, and tuck pointing wheels.
(c) Cup wheels. Cup wheels (Types 6 and 11) shall be protected by:
(1) Safety guards as specified in this section; or
(2) Special “Revolving Cup Guards” which mount behind the wheel and turn with it. They shall be made of steel or other material with adequate strength and shall enclose the wheel sides upward from the back for one-third of the wheel thickness. The mounting features shall conform with all regulations. (See Section 3580.) It is necessary to maintain clearance between the wheel side and the guard. The clearance shall not exceed one-sixteenth inch; or,
(3) Some other form of guard that will insure as good protection as that which would be provided by the guards specified in subsections (a) and (b) of this section.
(d) Vertical portable grinders. Safety guards used on machines known as right angle head or vertical portable grinders shall have a maximum exposure angle of 180 degrees, and the guard shall be so located so as to be between the operator and the wheel during use. Adjustment of guard shall be such that pieces of an accidentally broken wheel will be deflected away from the operator. (See Figure A-22 of Appendix E.)
(e) Other portable grinders. The maximum angular exposure of the grinding wheel periphery and sides for safety guards used on other portable grinding machines shall not exceed 180 degrees and the top half of the wheel shall be enclosed at all times. (See Figure A-23 of Appendix E.)
(f) Mounting and inspection of abrasive wheels.
(1) Immediately before mounting, all wheels shall be closely inspected and sounded by the user to make sure they have not been damaged in transit, storage, or otherwise. The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel.
(2) Grinding wheels shall fit freely on the spindle and remain free under all grinding conditions. A controlled clearance between the wheel hole and the machine spindle (or wheel sleeves or adaptors) is essential to avoid excessive pressure from mounting and spindle expansion. To accomplish this, the machine spindle shall be made to nominal (standard) size plus zero minus .002 inch, and the wheel hole shall be made suitably oversize to assure safety clearance under the conditions of operating heat and pressure.
(3) All contact surfaces of wheels, blotters, and flanges shall be flat and free of foreign matter.
(4) When a bushing is used in the wheel hole it shall not exceed the width of the wheel and shall not contact the flanges.
TABLE A-1 MINIMUM DIMENSIONS FOR STRAIGHT RELIEVED FLANGES
 
A *
B
C
D
E
Minimum
Radial Width of
Minimum
Minimum
Outside
Bearing Surface
Thickness
Thickness of
 
Diameter
Diameter of
of Flange
Flange at Edge
of Wheel
Flanges
Minimum
Maximum
at Bore
of Recess
 
Inches
Inches
Inches
Inches
Inches
Inches
1
1/16
1/16
1/16
2
¾
3/16
3/33
3
1
3/16
3/16
3/33
4
1⅛
3/16
3/16
5
3/16
¼
¼
6
2
¼
½
3/16
7
¼
3/16
8
3
¼
½
3/16
10
3/16
¼
12
4
3/16
3/16
14
¾
½
3/16
16
½
1
½
3/16
18
6
½
1
20
7
22
7/16
24
8
¾
7/16
26
¾
½
28
10
¾
½
30
10
¾
36
12
1
2
¾
42
14
1
2
¾
48
16
2
1⅛
1
60
20
2
1⅛
72
24
1⅜
 
TABLE A-2
MINIMUM DIMENSIONS FOR STRAIGHT UNRELIEVED FLANGES FOR WHEELS WITH THREADED INSERTS OR PROTJECTING STUDS
 
B *
T
A
Minimum Outside
Minimum Thickness
Diameter of Wheel
Diameter of Flange
of Flange
 
Inches
Inches
Inches
1
2
1
3
1
3/16
4
1⅜
3/16
5
¼
6
2
Note: * Must be large enough to extend beyond the bushing. Where prong anchor or cupback bushing are used, this footnote does not apply.
TABLE A-3
MINIMUM DIMENSIONS FOR STRAIGHT ADAPTOR FLANGE FOR ORGANIC BONDED WHEELS OVER 1¼ INCH THICK *
 
E
B
D
Minimum
F *
Wheel Diameter
Wheel
Minimum
Minimum
Thickness of
(D-E)
Hole
Flange
Thickness of
Flange at Edge
Minimum
Diameter
Diameter
Flange at Bore
of Undercut
Thickness
 
Inches
Inches
Inches
Inches
Inches
Inches
12
4
6
½
to
5
7
½
14
6
8
½
 
Larger than
4
6
½
14
5
7
½
to
6
8
½
18
7
9
½
8
10
½
 
Larger than
6
8
1
18
7
9
1
½
½
to
8
10
1
½
½
24
10
12
1
½
½
12
14
1
½
½
 
Larger than 24 to 30
12
15
1
½
½
 
Larger than 30 to 36
12
15
1⅜
½
 
* For wheels under 1¼ inch thick F dimension shall not exceed 40% of wheel thickness.
TABLE A-4
MINIMUM DIMENSIONS FOR STRAIGHT FLANGES-FOR MECHANICAL GRINDERS
$12,500 S.F.P.M. to 16,5000 S.F.P.M.1
 
‘E‘ Minimum
‘B‘ Minimum
‘D‘ Minimum
Thickness of
F * (D-E)
Wheel
Wheel Hole
Flange
Thickness of
Flange at Edge
Minimum
Diameter
Diameter
Diameter
Flange at Bore
of Undercut
Thickness
 
20
6
8
1
½
½
20
8
10
¾
¾
24
12
15
2
1
1
30
12
15
2
1
1
36
12
15
2
1
1
 
1 FLANGES shall be of steel, quality SAE 1040 or equivalent, annealed plate, heat treated to R 25-30.
* For wheels under 1¼ inch thick F dimension shall not exceed 40% of wheel thickness.
TABLE A-5
MINIMUM DIMENSIONS FOR STRAIGHT FLANGES USED AS WHEEL SLEEVES FOR PRECISION GRINDING ONLY
 
E
B
D
Minimum
Minimum Outside
Minimum Thickness
Thickness of
Wheel
Diameter of
of Flange
Flange at edge
Wheel Diameter
Hole Diameter
Flange
at Bore
of Undercut
 
Inches
Inches
Inches
Inches
Inches
12 to 14
5
7
7/16
 
5
7
7/16
6
8
7/16
Larger than 14 to 20
8
10
7/16
10
11½
7/16
12
13½
7/15
 
8
10
¾
½
Larger than 20 to 30
10
11½
¾
½
12
13½
¾
½
15
17½
¾
½
 
12
13½
¾
½
16
17½
¾
½
Larger than 30 to 42
18
19½
¾
½
20
21½
¾
½
 
16
20
1
¾
Larger than 42 to 60
20
24
1
¾
24
29
1⅛
 
Note: These flanges may be clamped together by means of a central nut, or by a series of bolts or some other equivalent mans of fastening. For hole sizes smaller than shown in this table, use table A-1.
TABLE A-6
GUIDE FOR CONSTRUCTION OF BAND TYPE GUARDS
Maximum Wheel Speed 7000 SFPM
 
Maximum
Thickness
Distance
Minimum
Thickness
Minimum
between
Material
Diameter of
of Band
Diameter
Centers of
Specifications
Wheel
A
of Rivets
Rivets
 
Inches
Inches
Inches
Inches
Under 8
1/16
3/16
¾
Hot Rolled Steel SAE 1008
8 to 24
¼
1
Over 24 to 30
¼
 
TABLES A-7 through A-18
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New section filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
HISTORY
1. New NOTE filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).
HISTORY
1. New Tables A-7 through A-18 filed 7-26-78; effective thirtieth day thereafter (Register 78, No. 30).
2. Repealer of Tables A-7 through A-18 filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).

Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G

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