Section 408.10115. Machine spindles.

(1) A wheel or flange that is secured by a spindle nut shall have the direction of the thread opposite that of the spindle rotation  so that the nut will tighten as the spindle revolves.

(2)   A spindle shall be long enough to engage all the threads within  the nut.

(3)   Spindle threads shall extend inside the flange, but not more than halfway within the hole of the abrasive wheel.

(4)   The spindle shall not be larger than the nominal size, with the undersize tolerance limited as required to prevent a hazardous condition.

(5)   A spindle on which a threaded-hole wheel is  mounted  shall  be threaded to allow the abrasive wheel to be screwed flat against the  back flange. In addition, all of the following requirements  shall   be   complied with:

(a)    The direction of the thread shall be such that removing the abrasive wheel requires rotation of the wheel in the same direction that  it  turns when in use.

(b)   A spindle shaft shall not touch the bottom of a blind hole in an abrasive wheel.

(c)   A back flange that is specified in this rule  shall   be  flat, unrelieved, and square to the spindle axis.

History: 1979 AC; 1990 AACS.