On 2008-12-17, Michael Koblic wrote:
Wild_Bill wrote:
Something I discovered while looking at minilathe accessories is that
a MT3 to 3C adapter and drawtubes are available for using 3C collets
with the 7x models instead of using Morse Taper 3 collets.
These adapters are for use in any machine that has a MT3 spindle with
a 3/4" (.750") thru hole. This includes 7x models, South Bend and the
9x20 series lathes.
The 3C collets are self-releasing, so they don't need to be
driven/tapped out like the locking MT collets do.
Additionally, the 3C collets allow the material to pass thru the
collet, which MT collets don't. This allows longer lengths of
material to be fed thru the headstock.

OTOH am I correct to assume that I could use my MT3 collet set from my
mini-mill?

Yes -- though you might need to make a drawbar of the right
length for the lathe's spindle. It is likely to be longer than that on
the mill (or at least different).

Check the thread pitch on the drawbar for the mill, and see
whether it is in the lathe's list of threads.

And -- what you *won't* have that the 3C with the adaptor would
give you is the ability to pass long stock through the headstock
spindle, turn a part, part it off, advance the stock, and repeat. The
MT3 collets use a solid drawbar, not a hollow one as the 3Cs (and 5Cs)
use.

The MT3 collets are supplied only in a few sizes -- to fit the
common shanks of end mills. The 3C and 5C collet sets are available in
1/32" steps to handle almost everything you are likely to hold. (Though
1/16" steps are more common, since they are cheaper.)

Good Luck,
DoN.

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