RE: [CAD_CAM_EDM_DRO] Re: Timing Belts and Pulleys

I've bought many piloted pulleys and bored and keyed them to size.

I have never found one where the bore is really out of centre at least not
that you could measure with simple machine shop kit.

Nowadays to bore and key them we use an EDM wire machine, it's easier for
the keyway.

I have had some measured on a CGM, and the pilot is normally within 3 to 5
micron of the teeth, but not true to the outer belt guide rim, which is
perhaps what you are experiencing, but practically doesn't really matter.



If you are buying them piloted and out of centre, I hope you are demanding a
low price since they would appear to be seconds. The whole basis of buying a
pulley with a piloted bore is that the bore is centre and true to allow
simple machining.



Regs Mark



_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Steve Stallings
Sent: 19 November 2006 14:57
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: Timing Belts and Pulleys

>
> I just chuck them in the "Griptru" or 4 Jaw, clock the bore central

then

> bore them out.
>
> Steve Blackmore
> --
>

In my experience, this misses the main problem,
that the manufacturer supplied bores are often
off center as delivered. I get better results
from centering based on the outer diameter of
the teeth of the pulley.

Regards,
Steve Stallings





[Non-text portions of this message have been removed]