Collet for 618 spindle

As I have written before, the MT collet set is probably the lease expensive of the various collet sets. And if all that you use it for is to hold milling cutters, then it goes up to a larger size than the other type that was originally supplied by Atlas. But for holding work pieces it has the drawback of being available only in 1/16" increments whereas the other type was available in 1/64" increments. If you want to acquire the other type as well, have at it! They do turn up from time to time.

Also, although they were apparently discontinued by around 1940, Atlas did originally make a model 612 as well as the 618. I think that we have had 2 or 3 turn up on here. They are about as rare as the Craftsman 101.07300.
 
If anybody is interested , I found some information on the original Atlas collet offering for a 6" , it would work on a 618-612 as well of course .
By the way I have had no luck finding any 6AT collets .
Mark .
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Interesting the 6 inch model has a capacity of just over 1/4 inch stock.

It would be possible to use a MT2 - ER16 collet chuck (Gives 1/32 to 3/8 stock holding) in the lathe with a hollow drawbar. Drill thorough the bottom of the ER16 chuck to allow stock pass through large enough for largest stock allowing room to rethread. Maybe cut down the MT2 shank to have a larger diameter to work with and less depth of drill needed. Then rethread the bottom of the MT2 taper to allow a hollow tube to be used as the drawbar. So you get up to at least 9/32 inch pass through stock.

For the handle side of the drawbar you need to make an adapter with a taper that will go inside the spindle to hold the drawbar in the middle of the spindle so it is square and won't cause vibration.

Hmm, maybe talking myself into making one... Probably look for the cheapest MT2 - ER16 collet holder so less likely it is hardened for easier drilling...

I use my MT2-ER25 chuck already but no stock pass through to work on the end of a shaft...
 
I like to find original stuff for my lathe , this collet set up (M6-750) would be an example of that . There is a guy selling this set up on the bay right now , I want it but I don't need it . I think if he had all the 6AT collets , I might buy . My MT2 - draw bar set up is all I need . If I needed through hole capability , there are a few sources for a ER chuck . Most are for a 1"-10 spindle nose , I'm 1"-8 . Here is a discussion on that . https://www.hobby-machinist.com/threads/er-32-collet-chucks-for-a-c-lathes-with-1-10-tpi.77932/
Mark .
 
I would go with the ER32 set up. A lot more collets available. Thru bore work holing on longer pieces also.....
 
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