Collet Chuck Questions

[SuperDave]

For those that use collet chucks:

1. What size collets do you use? (ER16, ER25, ER32...???)
2. What are the sizes you use most frequently for (a) Pens, (b) bottle stoppers (c) Other
3. If you use a MT collet system, do you "HAVE" to use a draw-bar?
4. What is the "acceptable" run-out on a MT collet system? Is .0006 acceptable?


May have more questions as I research my options...

Thank,

Dave

 

[alamocdc]

I have the Beall and it uses ER-32. I bought a set of 15 (up to 3/4"), but I don't remember the smallest... 1/4" I think.

 

[hilltopper46]

3. If you use a MT collet system, do you "HAVE" to use a draw-bar?
4. What is the "acceptable" run-out on a MT collet system? Is .0006 acceptable?

Yes, you have to be able to pull the collett into the morse taper in the head stock. You will also need to knock it out with a hammer.

IMHO a bit over half-a-thousandths (0.0006) would be acceptable. Most people can feel ~0.0015 or a bit more with their fingernail. A hair (really) is 2 or 3 thousandths.

 

[Randy_]

Originally posted by SuperDave
<br />For those that use collet chucks:.....2. What are the sizes you use most frequently for (a) Pens, (b) bottle stoppers (c) Other
3. If you use a MT collet system, do you "HAVE" to use a draw-bar?

Pen turners require a 1/4" collet to hold the 7mm or "A" mandrel and a 5/16" collet to hold the 8mm or "B" mandrel. I've never done bottle stoppers so I don't know what you need for them.

This is a fine distinction; but does need to be made. MT collets "MUST" be used with a draw bar. MT collet chucks may or may not need a draw bar depending upon the setup. If you are turning with a live center in the tailstock, a drawbar would not be necessary. If you are turning with the tailstock end of your work unsupported, use of a draw bar would be prudent; but I am sure there are those who try to get away without one.

 

[Randy_]

Originally posted by alamocdc
<br />I have the Beall and it uses ER-32. I bought a set of 15 (up to 3/4"), but I don't remember the smallest... 1/4" I think.

I suspect that Billy's collet set might be the 11 collet set in 1/16" increments from 1/8" to 3/4" sold by 800watt on eBay. But it might also be the set sold in 1/32" increments that contains 18 collets. Don't know why it is done; but this set skips the 13/32", 21/32" and 21/32" collets.

 

[SuperDave]

[quote
Yes, you have to be able to pull the collett into the morse taper in the head stock. You will also need to knock it out with a hammer.
[/quote]

I was under the impression that some MT collet chucks employed an eccentric ring style chuck collar that threaded onto the front of the collet chuck and compressed the collet. The MT end of the chuck was used to hold the chuck in the headstock... similar to the Woodcraft setup.

It would seem to me that the drawbar would add security in place of the tailstock but would it be absolutely necessary in turning a pen, especially after the blank was roughed to a cylinder?

<br />

 

[scubaman]

Originally posted by SuperDave
<br />

Yes, you have to be able to pull the collett into the morse taper in the head stock. You will also need to knock it out with a hammer.

I was under the impression that some MT collet chucks employed an eccentric ring style chuck collar that threaded onto the front of the collet chuck and compressed the collet. The MT end of the chuck was used to hold the chuck in the headstock... similar to the Woodcraft setup.

What he meant was you need to be able to knock out the collet holder. The collet itself is self-extracting - one of several mechanisms for that is built into the nut.

It would seem to me that the drawbar would add security in place of the tailstock but would it be absolutely necessary in turning a pen, especially after the blank was roughed to a cylinder?

Why even argue about it? A piece of threaded rod, a nut and a turned spacer of some sort is all that's needed and inexpensive. You can get fancier of course. I employ such a chuck on my metal lathe and have it such that I can extract the chuck w/o use of a hammer which is not the best thing for bearings.

As to your tolerance question: .0006" TIR is good and definitely adequate for pens. Most people have more in the mandrel itself.

I use all sizes - the ones under 1/4" the least. Most common are 1/4" and 5/16" for holding mandrels. Other sizes for all teh other stuff I do... from holding bushings to custom mandrels...

 

[Aderhammer]

Originally posted by hilltopper46
<br />

A hair (really) is 2 or 3 thousandths.

Actually it can be as thin as 1 thousandth. Measured mine in engineering and it's exactly one thousandth of an inch.