MT#4 to collet?

[Bill Kahn]

I have a PM1030V lathe.
http://www.precisionmatthews.com/wp-content/uploads/2017/01/Spec-Sheet-1022V1030V.pdf
Having a blast.

I want to be able to turn a part around--when I do that though the chuck jaws chew up the lovely OD I just made. I have tried wrapping with thin copper. Sort of works. And sort of a pain (I guess I will get better.). And ensuring the new axis of rotation is exact on the original one--a real pain. I am slowly learning to indicate in (even on the three-jaw) but it is painstaking.

So, I figure a collet system.

My question--how do I connect the MT#4 internal spindle taper to a collet system? I have some R8 collets for the mill. Is there an adapter for that? Or which collet system is best to connect to the MT#4? ER32? ER40? Why one or the other? Other options? Pointers to anything I can read on this are always welcome. Opinions and experience are of particular interest.

And, related, what if I am working on say a 2" OD and want to turn the piece end-for-end? Any efficient system for doing that? Or just protect with copper and carefully indicate in?

-Bill

 

[Downwindtracker2]

I picked up some TG 100 collets and will be using on my lathe. I have them for my mill as well. I have an R-8 to TG 100 chuck. They are very industrial. But in my searching about the TG, the ER collets were very highly rated and much more common than my TG 100. It was suggested the ER were a much better option.

 

[brino]

MT4 collets are less common than MT2 and MT3, but can be had:

https://www.ebay.com/itm/4-Morse-Ta...132253576490?_trksid=p2385738.m4383.l4275.c10

The above set uses a 1/2"-13 threaded draw bar which is easy to make custom length from threaded rod.
The use of a draw bar does mean you can only hold a limited length of piece.

Here's some useful reading:
http://hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/post-308226
http://hobby-machinist.com/threads/need-advice-about-lathe-collets.59971/
http://hobby-machinist.com/threads/collet-help.54008/#post-448345

-brino

 

[mikey]

Bill, if that were my lathe, I would buy a back plate from Matt and attach an ER-40 chuck to it. The ER-40 series collets go up to 1", which just happens to be the bore capacity of your spindle. This allows you to pass long work pieces through the spindle while holding them solidly with the ER collet. It doesn't make sense to use an ER-32 system that only goes to 3/4" capacity, right? You are right in that a collet will grab a finished work piece and do very little, if any, damage to the surface; this includes threaded sections.

Matt sells a 5" plate for your lathe, which will allow you to attach a 125mm diameter ER-40 chuck that is usually readily available on ebay. Tormach also sells one: https://www.tormach.com/store/index.php?app=ecom&ns=prodshow&ref=33286

You can use MT collets but they have a limited clamping range and will be expensive to cover a wide range of sizes. Very accurate, though.

You can also go with a 5C set up. Again, attach a 5C chuck to a back plate. Some guys really like the 5C system but most hobby guys don't always work with nominal sized stock so an ER system is more flexible.

And, related, what if I am working on say a 2" OD and want to turn the piece end-for-end? Any efficient system for doing that? Or just protect with copper and carefully indicate in?

Your best bet here is a good 4 jaw chuck and a decent dial indicator. A 4 jaw chuck is necessary if you need to re-chuck something accurately so I suggest getting really good with one; it is extremely handy to have.

I use aluminum flashing instead of copper and it works well. If I'm really concerned about marring the work piece I wrap it with several pieces of tape, insert the flashing and then indicate the work true. You cannot take huge cuts like this but if you take your time, it works pretty well.

 

[talvare]

If your chuck has two piece jaws, make or buy yourself a set of aluminum soft jaws. These are very useful for many lathe operations and can be modified to fit exactly just about any configuration you may need.

Ted

Here's an example : http://www.abbottworkholding.com/chuck-jaws-jaw-nuts/american-standard-tongue-groove-jaws

 

[Downwindtracker2]

ER collets hold better than either R-8 or 5C. flatter angle.

 

[Bob Korves]

ER collets hold better than either R-8 or 5C. flatter angle.

ER collets work better in some situations, in others not as well. Same with R8 and 5C. Each have their advantages and disadvantages. It depends a lot on what kind of work you do and how you use them.

 

[brino]

Beall Tool (USA!) has the smaller ER32 collet adapter: http://bealltool.com/products/turning/colletchuck.php
and a bigger ER50: http://bealltool.com/products/turning/bigchuck.php

You would need a back plate to fit either to the lathe.
-brino

 

[Moper361]

Do you have a good 4 jaw indipendant chuck if so this is what i used

I machined a er40 collet chuck up and made it with bore going all the way through then mount it in the 4 jaw chuck and dial it in with zero run out seems to be fine for what i do and the work piece can go right through the chuck .All it cost was a to buy a small bit of material and a er nut total about 10 dollars as i brought 3 er nuts for 8 dollars .I also made mt5 to er40 collet chuck that will fit direct into my lathe spindal however i prefer tbe chuck that is held by 4 jaw chuck

 

[woodchucker]

So I use copper or aluminum on my jaws. But there is another way. And that's to make a holder that fits the item you turned. You bore it to size, then turn the outside down to a reasonable size, then cut a slit in it. The slit will allow you to clamp down on it and grab your part in the chuck.
Very effective and protects the part. Aluminum is a good material. Make it thin that you can easily tighten down on it, but thick enough to protect your piece. Save it when you are done.