E40 COLLETS

[riversidedan]

been looking at e40 collets and see they have back plate then diffrent size collets that attach to the back plate....not .knowing anything about these things am assuming the collet back plate takes the place of the regular chuck plate so u can use different size collets.....is that correct? if so why use collets when u can just stick the part in the regular chuck....

 

[MikeInOr]

A good collet setup will have considerably less runout than a 3 jaw chuck. An independent 4 jaw chuck can be adjusted for minimal runout but that takes time. Collets are a quick way to mount work with minimal runout.

The back plate is used to mount a collet chuck to your lathe just like a backplate is used to mount a regular chuck. Usually you mount an oversized collet chuck backplate to your lathe then turn it down to fit the collet chuck. By doing this you are making the mounting shoulder on the backing plate concentric with your lathe spindle. When mounting the collet chuck on the turned back plate it too will be concentric to the spindle. This is part of reducing the runout of the collet chuck and collets to an absolute minimum.

 

[riversidedan]

A good collet setup will have considerably less runout than a 3 jaw chuck. An independent 4 jaw chuck can be adjusted for minimal runout but that takes time. Collets are a quick way to mount work with minimal runout.

The back plate is used to mount a collet chuck to your lathe just like a backplate is used to mount a regular chuck. Usually you mount an oversized collet chuck backplate to your lathe then turn it down to fit the collet chuck. By doing this you are making the mounting shoulder on the backing plate concentric with your lathe spindle. When mounting the collet chuck on the turned back plate it too will be concentric to the spindle. This is part of reducing the runout of the collet chuck and collets to an absolute minimum.

so the collet inserts must be only good for round stock

 

[stupoty]

You can hold threaded parts without damage in collets very easily.

Also useful for collet blocks for holding round stuff in mill or drill and basic indexing.

Stu

 

[SouthernChap]

so the collet inserts must be only good for round stock

Yep. The main reason to use a collet chuck on a lathe is to hold a workpiece securely and precisely and allow you to maintain concentricity.

This is a good video on collets and collet chucks dealing with the main types of collets:

One thing not focused on in the video is that stock isn't the only thing you can hold in collets when used with a lathe. You can hold tooling like milling cutters.

You shouldn't hold milling cutters in the jaws of your lathe chucks, but with a collet chuck you can hold an end mill or a slot drill or even a dovetail cutter in the collet chuck and a workpiece (of whatever shape) in a vertical milling slide (or an angle plate) fitted to your cross slide and do milling on your lathe.

Just as a heads up, the word collet refers to the 'insert' and you put collets in a 'collet chuck' (or 'collet holder' if you're using collets on your mill).

 

[Ischgl99]

so the collet inserts must be only good for round stock

You can get 5c collets for square and hex stock, but I believe ER collets only come in round. 5c also has emergency collets that allow you to machine the particular size you need if it is not a common dimension. The nice part about 5c is the back end has internal threads so you can install a work stop to get repeatable positioning when machining multiple parts.

 

[WobblyHand]

www.maritool.com sells specialty ER collets. They have hex collets in ER40. I bought a hex collet in ER32. I used mine to machine a Chapman screwdriver bit for a specific use. These special collets are not cheap, but if you need one, they work well.

Generally ER collets are for round stock or tooling. Unlike a 5c, there's no threading in ER collets, so adding a stop requires more ingenuity. But ER collets have a wider grip range for a size, reducing the number of collets needed.

Whenever possible I like to use the collets in my lathe as they have minimal run out. (I've measured them.) Just chuck and go. You can flip a part without much worry, save for the most critical applications.

 

[ChazzC]

www maritool.com sells specialty ER collets. They have hex collets in ER40. I bought a hex collet in ER32. I used mine to machine a Chapman screwdriver bit for a specific use. These special collets are not cheap, but if you need one, they work well.

Thanks for the link! As you say, not cheap, but if needed a great custom alternative. I also like the extended nose versions they have, and the storage options.

 

[markba633csi]

One caveat: I have heard those import collet chucks sometimes have a lot of runout- make sure you can return it if you get a bad one

 

[Ischgl99]

www.maritool.com sells specialty ER collets. They have hex collets in ER40.

Thanks for that, I don’t think I ever saw their hex ER collets, I will have to keep that in mind for the future. I noticed they have ER floating tap collets too for a decent price, I might get one to try out.