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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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§3579. Flanges--General Requirement.

(a) All abrasive wheels shall be mounted between flanges which shall not be less than one-third the diameter of the wheel.

EXCEPTIONS:

(1) Mounted wheels.

(2) Portable wheels with threaded inserts or projecting studs.

(3) Abrasive discs (inserted nut, inserted washer and projecting stud type).

(4) Plate mounted wheels.

(5) Cylinders, cups, or segmental wheels that are mounted in chucks.

(6) Types 27 and 28 wheels.

(7) Certain internal wheels.

(8) Modified Types 6 and 11 wheels (terrazzo).

(9) Cutting-off wheels, Types 1 and 27A:

(A) Type 1 cutting-off wheels are to be mounted between properly relieved flanges which have matching bearing surfaces. Such flanges shall be at least one-fourth the wheel diameter.

(B) Type 27A cutting-off wheels are designed to be mounted by means of flat, not relieved, flanges having matching bearing surfaces and which may be less than one-third but shall not be less than one-fourth the wheel diameter. (See Figure A-13 of Appendix C for one such type of mounting.)

NOTE: There are three general types of flanges:

1. Straight relieved flanges. (See Figure A-16 of Appendix D.)

2. Straight unrelieved flanges. (See Figure A-17 of Appendix D.)

3. Adaptor flanges. (See Figures A-18 and A-19 of Appendix D.)

(b) Regardless of flange type used, the wheel shall always be guarded. Blotters shall be used in accordance with subsection (g) of this section.

(c) Finish and Balance. Flanges shall be dimensionally accurate and in good balance. There shall be no rough surfaces or sharp edges.

(d) Uniformity of Diameters.

Both flanges, of any type, between which a wheel is mounted, shall be of the same diameter and have equal bearing surface.

EXCEPTIONS:

(1) Type 27 and Type 28 wheels because of their shape and usage, require specially designed adaptors.

(2) Modified Types 6 and 11 wheels (terrazzo) with tapered K Dimensions.

(e) Mounts which are affixed to the wheel by the manufacturer shall not be reused. Type 27 and Type 28 wheels shall be used only with a safety guard located between wheel and operator during use. (See Figure A-14 and A-15 of Appendix C.)

(f) Recess and Undercut.

(1) Straight relieved flanges made according to Table A-1 and Figure A-16 shall be recessed at least one-sixteenth inch on the side next to the wheel for a distance as specified in Table A-1.

(2) Straight flanges of the adaptor or sleeve type (Table A-4 and Figures A-18 and A-19) shall be undercut so that there will be no bearing on the sides of the wheel within one-eighth inch of the arbor hole. (Figures A-18 and A-19 are illustrated in Appendix D.)

(g) Blotters. Blotters (compressible washers) shall always be used between flanges and abrasive wheel surfaces to insure uniform distribution of flange pressure. [See Section 3480(e).]

EXCEPTIONS:

(1) Mounted wheels.

(2) Abrasive discs (inserted nut, inserted washer, and projecting stud type).

(3) Plate mounted wheels.

(4) Cylinders, cups, or segmental wheels that are mounted in chucks.

(5) Types 27 and 28 wheels.

(6) Certain Type 1 and Type 27A cutting-off wheels.

(7) Certain internal wheels.

(8) Type 4 tapered wheels.

(9) Diamond wheels, except certain vitrified diamond wheels.

(10) Modified Types 6 and 11 wheels (terrazzo)--blotters applied flat side of wheel only.

(h) Driving Flange. The driving flange shall be securely fastened to the spindle and the bearing surface shall run true. When more than one wheel is mounted between a single set of flanges, wheels may be cemented together or separated by specially designed spacers. Spacers shall be equal in diameter to the mounting flanges and have equal bearing surfaces. [See Section 3480(f).]

(i) Dimensions.

(1) Tables A-1 and A-2 and Figures A-16 and A-17 of Appendix D show minimum dimensions for straight relieved and unrelieved flanges for use with wheels with small holes that fit directly on the machine spindle. Dimensions of such flanges shall never be less than indicated and should be greater where practicable.

(2) Tables A-3 and A-4 and Figures A-18 and A-19 of Appendix D show minimum dimensions for straight adaptor flanges for use with wheels having holes larger than the spindle. Dimensions of such adaptor flanges shall never be less than indicated and should be greater where practicable.

(3) Table A-5 and Figure A-19 of Appendix D show minimum dimensions for straight flanges that are an integral part of wheel sleeves which are frequently used on precision grinding machines. Dimensions of such flanges shall never be less than indicated and should be greater where practicable.

(j) Repairs and maintenance. All flanges shall be maintained in good condition. When the bearing surfaces become worn, warped, sprung, or damaged they should be trued or refaced. When refacing or truing, care shall be exercised to make sure that proper relief and rigidity is maintained as specified in subsection (f) of this section and they shall be replaced when they do not conform to this subsection and Table A-2, Figure A-17, Table A-3, Figure A-18, Table A-1, Figure A-16, and Table A-5, Figure A-19. Failure to observe these rules might cause excessive flange pressure around the hole of the wheel. This is especially true of wheel-sleeve or adaptor flanges. (Figures A-16, A-17, A-18 and A-19 are illustrated in Appendix D.)

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.

HISTORY

1. Amendment filed 7-26-78; effective thirtieth day thereafter (Register 78, No. 30).

2. Repealer of subsections (d), (e) and (f) and relettering of existing subsections filed 2-20-80; effective thirtieth day thereafter (Register 80, No. 8).

3. Amendment of subsections (j), (k), (l) and (p) filed 7-8-85; effective thirtieth day thereafter (Register 85, No. 28).

4. Repealer and new section filed 11-22-85; effective thirtieth day thereafter (Register 85, No. 48).

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