Adding a 2 groove pulley to motor shaft

OK. I am "following" two "threads" having to do with a need for either M6-428 (the 1/2" bore 2-step otor pulley that is no longer made) or M6-429 (the 5/8" bore 2-step motor pulley that is still available). Must have been the other one that needed both M6-427 and M6-428.

For the edification of ALCON (all concerned), sometime between the printing of the 1945 and the 1950 Atlas 6" parts manuals, Atlas discontinued the M6-428 and only made the M6-429. Apparently if you needed the former (1/2" bore motor pulley), you got the latter plus a 5.8" x 1/2" reducing sleeve or bushing. This quickly became the standard way of doing things for most US companies. The reducing bushing was most often made of steel and had a slot to clear the key, which the set screw (or one of them) tightened against, instead of bpth being against the bushing. Apparently, if you ordered the M6-428, you were supposed to automatically get the M6-429 and the bushing.
 
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