Lathe collets

Can someone please clue me in on the difference between 3C and 3AC collets? I have a handwheel type collet closer for my 10" South Bend and some collets that are marked 3C but they will not tighten down on the stock. Any and all information offered will be much appreciated by this relative newbie.


Nick Faymoville

Reply to
Nick Faymoville
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Are you sure that those 3AC collets aren't 3AT? The latter were used by the Atlas/Craftsman lathes and probably other brands (logan?). 3C and 3AT collets look identical at first glance but there are some differences. The nose taper and length, I think.

Reply to
Mike Henry

I'm not sure of the 3AC type, but the SB typically uses 3C collets.

3AT are quite similar and would work in a 3C setup, but not the other way round. To use 3C in a machine that wants 3AT one must lengthen the keyway on the 3Cs.

Suggest you give a better description of how they don't grip the stock in your machine. Does the drawbar not thread onto the collet all the way? Ie drawbar crossthreaded? Or is the drawbar too long or too short?

Maybe the key inside the nosepiece is smeared over and the collet is not dropping in all the way?

Exactly where are things binding up is what I'm asking.


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Reply to
jim rozen

Logan's website (sorry, I don't have the URL handy) has the dimensions on most of the types of collets.

Reply to

Jim, thanks for your input. I'm sure you are correct - I am trying to use

3C collets with a 3AT drawbar and nosepiece. The keyway on the 3C collets is too short to allow the collet to close completely. Thanks to you and others for the help.


Reply to
Nick Faymoville

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