On Jun 26, 2:27*pm, Searcher7 wrote:
On Jun 19, 6:55*pm, Jim Wilkins wrote:
...

And I assume deflection is why steady rests were made.

...Follower
rests don't help if the part has shoulders. If you tried to turn a 6"
length of 1/4" aluminum without the tailstock it would just climb up
onto the lathe bit.

Of course. (But I don't know what you mean by shoulders).

Changes in diameter. The gauge with all the different threads has
shoulders or steps between sizes. It's too short for a steady rest and
a follower rest would hit or fall off the steps even if they weren't
too rough. IIRC I threaded the first half with it held in a collet,
then tightened a nut on one of the threads for a lathe dog and
threaded the second half between centers.


Yes. My determination is that with my lathe 9/16" would be the maximum
diameter I could pass through the spindle using 3C collets, because
that is the largest diameter these collets are made for.

Higher than that would require a 5C collet chuck for the 5C collets.

Not if you needed to turn some 3/4" thin walled brass tubing, or thin
a washer, or remove the part to test a fit and then replace it to cut
some more, or turn it around to machine the other end, or file it
without risking precious body parts, or face a batch of pieces to the
same length. An MT3 collet would be fine for all those.

But Isn't MT3 a "tool holding" collet?

We don't have Purity Police in NH. It's a "something round holding"
collet. If that something is long it belongs in a hollow work holding
collet, if short either will do. They both grip well enough to
withstand the forces of cutting metal. If you want to be an inventor +
machinist, look beyond what things are "meant" to do.

Ask yourself why they are used on rotary tables. An MT2 collet holds
the centering rod he
http://picasaweb.google.com/KB1DAL/H...10360947850418

But wouldn't an MT2 dead center be better?

A pointed dead center wouldn't have held the blank while I slid the
parallels into place and tightened the bolts. Faceplate setups are
awkward. Theoretically a dead center might give better centering
accuracy IF the hole wasn't burred or unevenly countersunk, but this
is only the steering gear for a garden tractor.

In this case the blank would be located by too many points unless the
center is spring loaded, and then you couldn't tell if the blank
shifted and pushed the center inward when the bolts were tightened.

These are $309 in Enco's latest flyer:
http://www.kalamazooind.com/products...re-for-chucks/

I think the right place for 5C collets is in the spindle of a lathe
meant for them, but you could clamp that in a 4-jaw.

jsw