Re: collets

--- In CAD_CAM_EDM_DRO@y..., dougrasmussen@c... wrote:

> initial statement, I'm pessimistic about "home-made" collets.
>
> You've both mentioned the use of a spindle as a holder in final
> sizing the collet's ID. That's "cheating", since the collet then
> becomes spindle-dependent and not general purpose. IMHO, a collet
> should be concentric and accurate by itself, making it
> interchangeable between machine spindles. That's the part where I
> see the major problems.

We described methods that you can use to make a collet that will be
as good or better than the id taper of your spindle. That's as good
as it gets and if you spend the money to make it better, the quality
of the work held will not improve. Typical TIR on a spindle ID is no
better than .0002 for a good lathe with a couple years service. For
a home shop machine they usually are not that good out of the box.

> Fred, it's not my experience that the typical CNC shop is about to

go

> out of business. Where are you located that you see this?

USA. Watch the Auction listings to get a feel for the action. Many
of the CNC shops have one or two contracts that comprise a major
portion of their cash flow and volume. If they have trouble with the
customer they have business distress. Automotive is one of the
largest sectors in this business and it has been sputtering since
last spring. Commercial aircraft took a major nosedive in
September. Electronics is in the toilet. Work continues to be sent
from US to Mexico, China, Thailand, Malasia, etc, chasing the $/hr or
equivalent. I am referring to metal working and jobshop type of
work, not wood, fab, or vertical product oriented companies that
control their own destiny a little differently and are not usually
thought of as CNC businesses.

Best Regards, Fred Smith- IMService
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