Re: [CAD_CAM_EDM_DRO] Re: Timing Belts and Pulleys

Steve Blackmore wrote:

>On Sun, 19 Nov 2006 18:52:05 -0600, you wrote:
>
>
>
>>Mark Vaughan wrote:
>>
>>
>>
>>>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.
>>>
>>>
>
>I've got to agree with Mark - I've bought Chinese makes from RS and my
>local bearing stockist, and also from HPC Gears (who make their own).
>
>Never had one where the bore wasn't concentric, including sintered.
>
>
>
>>I have bought them at various times from W. M. Berg, SDP and McMaster-Carr.
>>ALL had easily measurable runout! Just use a dial caliper from the bore
>>to the
>>OD and take 3 measurements at random around the circumference. I've never
>>seen one that was better than a few thousandths of an inch, ie. easily
>>measured.
>>
>>
>
>Send them back and change suppliers.
>
>
>

OK, if W. M. Berg, Stock Drive Produts/Sterling Instrument and McMaster
Carr are out, where
do you get YOUR pulleys from? I'm not quibbling about a couple
thousandths of an inch, that
is certainly acceptable for this use, but when you can see the
eccentricity, that's pretty bad.
Not all of them are that bad, however.

Jon