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Unread 26-11-2011, 10:54
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Re: Timing Pulley Stock - Machining Question

Quote:
Originally Posted by Ninja_Bait View Post
If you're a lazy machinist who doesn't want to find a collet or make one, can you just wrap it in a thin layer of tape or a piece of belt?
Neither would be acceptable from a safety or accuracy standpoint. They simply cannot grip the workpiece well enough.

Another idea for a collet of sorts, assuming a 4-jaw is not available, is a band of metal about 3/32" thick, bent into most of a circle the size of the workpiece. The ends are left unconnected and separated by a distance about 1/6 of the circumference. You grip at all three jaw locations onto solid metal, which can contract to grip the workpiece. The metal is thick enough to not distort from the clamping forces, and since it rides on the teeth it will maintain concentricity.

For facing it's not important, but for boring the center hole it is.

Ah, yes: Don't "drill" the center hole, bore it with a boring tool, since a drill will wander and make an off-center hole, almost guaranteed.
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