(1) You must mount all abrasive wheels between flanges that have a diameter at least one-third the diameter of the wheel.

EXEMPTION:	This flange requirement does not apply to the following wheels:
	1. Mounted wheels (wheels permanently bonded to a shaft or mandrel).
	2. Abrasive disc wheels (inserted nut, inserted washer and projecting stud type).
	3. Plate mounted wheels.
	4. Cylinder, cup, or segmental wheels mounted in chucks.
	5. Types 27, 28, and 29 wheels.
	6. Internal wheels less than two inches in diameter.
	7. Modified Type 6 and 11 wheels (terrazzo).
	8. Types 1 and 27A cutting-off wheels.

(2) You must make sure flanges are:

(a) Dimensionally accurate.

(b) Properly balanced.

(d) Free of rough surfaces or sharp edges.

(3) You must make sure the driving flange is:

(a) Part of the spindle; or

(b) Securely fastened to the spindle.

(4) You must make sure, if a wheel is mounted between two flanges, that both flanges:

(a) Are the same diameter; and

(b) Have equal bearing surfaces.

EXEMPTION:	The following wheels do not require same diameter, equal bearing surface flanges:
	1. Types 27, 28, and 29 wheels with adaptors.
	2. Modified Types 6 and 11 wheels with tapered K dimension.
	3. Internal wheels less than two inches in diameter.