Re: [CAD_CAM_EDM_DRO] Timing Belts and Pulleys

Steve Blackmore wrote:

>On Sun, 19 Nov 2006 00:08:30 +0000, you wrote:
>
>
>
>>Jon Elson wrote:
>>
>>
>
>
>
>>>Depending on
>>>how accurately the hubs are bored, there may be some small cyclical error
>>>every turn. That's why I always buy the pulleys with undersize bores and
>>>bore them up to whatever size I need. I turn rings out of aluminum scrap
>>>that have an exact ID to match the pulley's OD, then split the rings.
>>>
>>>
>
>
>
>>Jon you need to make yourself some softjaws, much easier ;)
>>
>>
>
>I just chuck them in the "Griptru" or 4 Jaw, clock the bore central then
>bore them out.
>
>

If the original bore is off-center, then you have made an eccentric
pulley. Not a good idea where
positioning accuracy is important. On a number of pulleys, the runout
of the bore was
CLEARLY visible! So, I either use an indicator on the major OD or
something that will
guarantee centering the teeth. Also, on flanged pulleys you can't
assume the flanges
are concentric to the teeth.

Jon