Collet for Atlas Clausing ?

[minsk]

I purchased on-line an ER40 / MT2 with drawbar for my MK2. Not perfect, but I made a support for it that once the drawbar was set, I screwed (1"-10) my support against the back of the collet. It gave it considerable stability.

any pics sir?

 

[markba633csi]

There's a good writeup on making an ER collet chuck for an Atlas here:

Atlas 618 Lathe Projects

mark

 

[Skowinski]

There are basically three choices of collets for the Atlas 6", 2MT, the Atlas M6-751, and the smaller ER's.

If all that you need to do is hold milling cutters, the 2MT is probably the least expensive option. AFAIK the 2MT collets only came in 1/16" increments and each size only has a gripping range of about +/- 0.005". For gripping parts, you would be limited to 1/16" increments. So not a good choice for general use.

The M6-751 sold by Atlas is rare in a complete set and is almost certain to be the most expensive option. Plus the largest diameter that is available is 9/32". So I would judge it not a good choice unless your only need for collets was working on parts always under 5/16" diameter and you find the set cheap.

ER32 or ER25 holders or closers are available from several sources, or buy the nut and make the rest. There are three types or styles.

The first and least desirable is mounted on a 2MT arbor either with or without a draw bar. Avoid the one without a drawbar as sooner or later, the arbor will get loose in the taper and probably ruin the part. The arbor with drawbar works OK except that you can't pass long parts or stock through the spindle. And you need to use a spindle thread protector with it. However, it and the 2MT's are the only ones safe for machining with in Reverse.

The second type is mounted on a face plate that screws onto the spindle. The only disadvantage to this one is that it sticks out farther than the others. It is advantageous to a seller as the same chuck or closer can fit a face plate for any lathe.

The third type screws directly onto the spindle and in most cases is the preferred type.

That's a nice summary of options, thanks!

There's a good writeup on making an ER collet chuck for an Atlas here:

Atlas 618 Lathe Projects

mark

I hadn't ran across that website, lots of good information there. The collet closer chuck is beyond my skill level, for now anyway...

 

[T Bredehoft]

any pics sir?

I"ll try with an image.

It and the lathe it goes with. (Pix maybe available, I've Photoshop, can't tweak images) are on the market. I"d like to sell it all at once to someone needing a small reliable lathe.

 

[wa5cab]

Tom,

If I understand your 2MT to ER setup, the actual collet chuck screws onto the part with the 2MT arbor sticking out its left end. What are the threads between the collet chuck and the 2MT adapter?

 

[wa5cab]

Skowinski,

Where did I write what you copied? I just noticed that I left out the word "collets" after "2MT" in the first sentence of the second paragraph. I added it to what you copied but would go back and add it to the original.

 

[T Bredehoft]

Robert

Tom,

If I understand your 2MT to ER setup, the actual collet chuck screws onto the part with the 2MT arbor sticking out its left end. What are the threads between the collet chuck and the 2MT adapter?

The collet chuck is mouted on the 2MT, solid. the collar behind the chuck is free floating in the image, but screws onto the 1 10 nose of the spindle, then lightly pushes against the back of the collet chuck, to give it more stability. I suspect that if it were tightened too much it could affect concentricity. Without the collar, the chuck is fairly limber.