PDA

View Full Version : Atlas 6" spindle / collet



Rough Cutting
10-19-2005, 12:35 PM
My lathe is an Atlas 6" with a spindle threaded 1-10 and has a No. 2 morse taper. I have a set of Morse taper collets to 1/2 and use them, but often I would like to chuck longer material and not have to close with a draw bar. Is there a collet design that will adapt to this size spindle?
Thanks, Gerry

SGW
10-19-2005, 12:46 PM
I think you want 3AT collets to go with that lathe. They have a capacity up to 1/2". Maybe somebody else can say for sure.

JCHannum
10-19-2005, 05:23 PM
I am not sure what the collet designation is, but the collet set supplied by Atlas for the 6" lathe only went to 9/32", not much use.

IOWOLF
10-19-2005, 05:48 PM
3AT collets are for the 10 & 12" lathes.IIRC

------------------
The tame Wolf !

ARFF79
10-20-2005, 01:50 AM
When I bought my Atlas 6"x18" in 1980, the paperwork stated that it used a 6AT collet along with the draw bar and nose cap. Until I sold the lathe I searched for those collets and never found any . Hardinge no longer made them, Clausing's parts list said they were discontinued and no one seemed to have any in "old old back stock". I wish you luck in finding them. your best bet would be to make a spindle nose adapter for ER collets.

[This message has been edited by ARFF79 (edited 10-20-2005).]

TGTool
10-20-2005, 11:14 AM
I'll second that suggestion. ER collets are widely available from all the industrial suppliers. They're front closing so you can use your full spindle through-hole. The closing nuts are available as replacements so the minimum machining would be the body (and a metric OD thread for the closer).

Jan M

Rough Cutting
10-20-2005, 07:00 PM
Thank you for your replies, I didn't think of ER collets. I will start to gather dimensions and get a closer and a few collets.
Thanks again, Gerry

Tinker2
10-20-2005, 07:37 PM
Rough Cutting

I too have a Atlas 6" with a spindle threaded 1-8 with a No. 2 Morse
taper. Let us (me anyway) know what you make, ER collets, or not.

Good luck

Rough Cutting
10-26-2005, 08:40 PM
I was sketching out an adaptor for ER 25 collets and it occured to me that I have a Jacobs headstock chuck I don't use very often. I chucked up a precision pin and indicated 1.2 thou TIR. I don't think I can do much better with a home made collet closer. I never would have guessed that the runout would be that small.

Gerry

J Tiers
10-26-2005, 10:25 PM
<font face="Verdana, Arial" size="2">Originally posted by Rough Cutting:
I chucked up a precision pin and indicated 1.2 thou TIR. I don't think I can do much better with a home made collet closer. I never would have guessed that the runout would be that small.
Gerry </font>

For collets that sounds large..... lots of 3 jaw chucks are almost that good... when new, anyhow.

By making yourself, you should be able to do better.

Why?

Because you will make it on the machine that will use it.. Once you get the OD and taper right, which is tricky, but quite do-able, then you will machine the inside with the closer in place.

That means you can mark its orientation with respect to something fixed, like the thread start on the spindle. Any errors will be reduced by always putting it back in with same orientation.

You should get in the tenths unless the spindle bearings are toast, or you are remarkably careless with the machining.

Machining in the spindle will mean you get it on axis even if the nose is bent, or the taper off center.... all it has to do is spin smoothly, and it has to be right... it generates a true cylinder.

Then if you put it back the same way, it will still be right.... (of course the error would be double if you put it in 180 deg away).



[This message has been edited by J Tiers (edited 10-26-2005).]

poway_bob
10-28-2005, 01:14 AM
Hi folks,
Years ago I bought a Jacobs headstock chuck.
#56B 0-17/32" 1"-10 Thread. It screws on the spindle. Not as good as a collet, but still pretty good.

Bob

JeffG
10-28-2005, 08:55 AM
There's an Atlas/Craftsman group on Yahoo that's dedicated to the 6" lathes. Someone there will probably have a source for collets, and perhaps plans/advice if you want to go the ER route.