In article ,
Tim Wescott wrote:

On 11/12/2010 07:51 AM, Bob La Londe wrote:
From the Sherline website.

"Due to the nature of the design of a 3-jaw chuck, it cannot be expected
to run perfectly true. Even 3-jaw chucks costing five times more than
the one made for this lathe will have a 0.002" to 0.003" runout. If
perfect accuracy is desired in a particular operation, the use of a
4-jaw chuck or a collet is recommended. Both are available for your
Sherline Lathe."

That's certainly been my understanding of 3-jaw chucks all along -- if
you want perfect accuracy you use a chuck with individually adjustable
jaws, and you run the part in with a dial indicator to establish runout
before you cut.

Or a collet, depending what you are doing and how fast you need to be
doing it (especially if it's over and over again on parts the same size.)

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