QMT High Precision Adjustable ER-40 ER Collet Chucks and 5C chucks in D1-4 and D1-5

[mksj]

At one point I tried using a ER40 block in my 4 Jaw chuck and the TIR/skew was a problem as well as being awkward. I see no reason to have a 5C to ER40 adapter, you are limited by the diameter of the 5C, you have more stick out from the chuck and more compounded TIR from stacking. By the time you are all said an done you would be better off just getting a direct mount ER40 chuck and a 5C chuck. I have both, I made my own ER40 set-true chuck, I only use it for odd diameter work and prefer the 5C. Technically an ER chuck system has more holding power if the stock extends the full length of the collet, but I have never had an issue with holding power of my 5C.

The other advantage I see for using a dedicated 5C or ER40 chuck is you can use your hands very close to the chuck without fear that a jaw is going to rip off a part of your finger. The main reason for my initially posting the information on these set-true style collet chucks was that they were nicely made, accurate and reasonably priced. I know a couple of people that purchased the QMT 5C set-true chucks and have been very satisfied with them.
Mark

 

[HighWall]

My issue is my lathe is a Clausing and requires a L00 backing plate. I already have a 5C chuck as well and a set of ER32 collets I use with my 935TV. I was just thinking how I might be able to use the ER collets on both tools without significant expense. The same makers have 5C to ER32 adapters.

 

[mksj]

Something you might consider, you can purchase a semi-finished back plate, and buy a ER32 lathe chuck to mount to it. I would turn/drill the hack plate to match the chuck. If you want a set-true type you could either buy one or modify something like the one below and add some small Allen screws to the perimeter. You should be under 0.001" TIR if you turn the back plate on the lathe.

6" L00 Semi-finished adapter Plate for LATHE CHUCKS #ADP-06-L00SM-NEW | eBay

L00 Semi-finished threaded back plate for 6" lathe chuck. Thread: L00 standard. Keyway cut ready by EDM wire cut.

www.ebay.com

ER32 Collet Chuck 100mm Diameter Compact Lathe Tight Tolerance for Milling US | eBay

Can also be used as a fixture on a milling table. Mount to your choice of backplate to use on a lathe. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing.

www.ebay.com

 

[Christianstark]

Here's how mine trues up on my 1340GT.

 

[Jake P]

This is a simple question that I can't seem to see an answer for anywhere I've looked. And not currently having, nor have I ever used, said collet chuck and collets I ask the following:

I suspect that like the ER40 chuck that PM offers (which I own), the 5C chuck can pass a long rod through the headstock? And that would hold true up to the max collet diameter of 1 1/8"?

 

[mksj]

The largest stock that can pass through a 5C is 1", and if it is 1-2 thousandth over probably not if you have a internally threaded 5C collet. The larger size 5C collets, are stepped to a depth of ~1.6".

 

[Christianstark]

This is a simple question that I can't seem to see an answer for anywhere I've looked. And not currently having, nor have I ever used, said collet chuck and collets I ask the following:

I suspect that like the ER40 chuck that PM offers (which I own), the 5C chuck can pass a long rod through the headstock? And that would hold true up to the max collet diameter of 1 1/8"?

The back is open to pass stock through the headstock. The collet is closed with a key on the side, so no obstructions through the headstock.

 

[Christianstark]

The largest stock that can pass through a 5C is 1", and if it is 1-2 thousandth over probably not if you have a internally threaded 5C collet. The larger size 5C collets, are stepped to a depth of ~1.6".
View attachment 391932

The PM 5C collets go to 1 1/8 per their website. I am guessing it will not pass through the back if over 1" stock?

 

[ahazi]

The PM 5C collets go to 1 1/8 per their website. I am guessing it will not pass through the back if over 1" stock?


View attachment 391934

This is correct, it is a stepped collet, all the way through up to 1.000". The PM set go up to 1-1/8". I can check again in the shop to make sure that my answer is 100% correct.

Ariel

 

[mksj]

If you look at the picture you posted you can see the step in the collets above 1". As I said the inside diameter of the 5C collet is spec. at 1" or less. When you get into larger diameter or longer stock above 1" I move to my 3J or 4J chucls which have higher holding power over a longer section of the rod.