On Tue, 14 Oct 2008 22:34:15 -0500, RoyJ
wrote:

The D series have a short taper that centers the chuck, along with 3
pins with cam holes to positively lock things into place.

I'll add my .02.
The number of pins varies with the size of the mount. A D1-5 like my
lathe has 6 pins, although my 5C collet closer only has 3 on it, I
guess they figure you can only put so much cutting force on a peice
small enough to go in a 5C collet.

Thank You,
Randy

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