# 3AT Collets and Holder Question - Help



## MBfrontier (Jan 2, 2014)

I recently purchased a Logan 200 Lathe and it came with some tooling. Some of the tools include a number of 3AT collets and a collet holder. I can see how the collets fit into the holder but cannot figure out how I can use this in the 6 inch 3 jaw chuck that came on the lathe. The 3AT collets mount in the holder and after tightening the screw end the center section spins. Also, the center section has four flats not three. Can you tell me if this should mount in my three jaw chuck or is this meant for another mounting style? Here are the pictures of a 3AT collet mounted in the collet holder:


----------



## kd4gij (Jan 2, 2014)

It is home made looks it is ment to mount in a 4 jaw independent chuck. That way you can indacate it on center. It would prity usless in a 3 jaw chuck.


----------



## Terrywerm (Jan 2, 2014)

3AT collets are normally meant to be used in the lathe with a number of parts:
1. Collet adapter
2. Spindle thread protector
3. Drawbar. 

See post #4 in this thread on how to use them:   http://www.hobby-machinist.com/show...ng-more-collet-advise-MT4?p=155439#post155439

The adapter that you have is not meant to be used in the four jaw chuck but is meant for mounting a part in the collet, and in turn mounting the whole thing in a mill vice to be able to mill flats on one or more sides of that round part. It could be mounted in the four jaw, but you would have to dial in the collet and the part each time that you mounted a new piece in the collet. This would defeat the purpose of using a collet, where repeatability and little runout are the name of the game.


----------



## MBfrontier (Jan 3, 2014)

Thanks, guys.

It doesn't look like I'll be able to use these 3AT collets and the holder that came with the tooling. I won't throw them away or sell them but maybe someday I'll come across a draw-in collet attachment for my Logan 200 Lathe and I'll be able to use them.

Thanks for the replies.


----------



## Terrywerm (Jan 3, 2014)

There are several collet attachments for Logan lathes on eBay right now if you are considering looking for one. There were a couple that use a handwheel drawbar and there was one that uses a lever drawbar. I don't care for the lever type as you have to remove the gear train cover in order to mount them. 

Another option would be to simply purchase a new 3AT spindle adapter for about $30 on eBay, then make your own thread protector and handwheel type drawbar. Then you would be all set. You could make your own adapter, but they are usually ground to final dimension, plus they have a small internal key. You would need a good working drawing or an adapter to copy if you were to make your own.

Keep in mind that I am not saying that you _should_ do that, I am only saying that you _could_ do that if you wanted to get set up for doing collet work. I like using collets when I am making things from smaller sizes of round stock, concentricity is pretty much guaranteed and the collet will hold it better than a three jaw will in those small sizes. With some of the smallest sizes, a collet is nearly the only way to go.

You can use your collet holder in the four jaw chuck, but will need to dial in your part each time you mount one since to remove the part you will need to remove the block from the chuck so that you can get at the nut on the back. On second thought, you could remove the four jaw chuck from the spindle to get at the nut, but that is almost as much work as just dialing in for each part.

Whatever you choose to do, you will probably at some point wish that you had the rest of the collet equipment and a full set of collets, especially if you make small parts for firearms or model engines.


----------



## MBfrontier (Jan 3, 2014)

Thanks, Wermie.

I think I'll let them set in the toolbox for now. I think I'll concentrate on my lathe restoration since I don't have a specific application for the collets. Since I am new to having my own lathe I was wondering how these work. Thanks for all of the input.


----------



## Terrywerm (Jan 4, 2014)

You are most welcome, MB. More than happy to help shed a little light on the subject for you.  Feel free to smother us with questions as your project continues.

And don't forget to share some pics as you go!


----------

