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Crazy Ed
07-17-2004, 02:26 AM
Being 'Crazy Ed' I was wondering IF you could make a 'cheap' collet closer by buying a nut to fit the spindle size and thread, Turn both sides flat and even then weld on a thick plate to one side that had been drilled out. Then, after welding it to one side, machine bevel to fit the front of the collets to 'close' them?

Just wondering.

Wouldn't that work?? And why/not.

SGW
07-17-2004, 06:50 AM
Not having specific details, it's hard to give a specific answer.

The collet closers I'm familiar with are tapered, to fit the internal taper of the headstock -- they don't screw on. I guess you're thinking of a different kind.

I seriously doubt you'd ever find a 1 1/2-8 or 2 1/4-8 nut, to buy -- again, you may be thinking of some other size that is available.

As for welding, I think you'd want to do all your welding before doing any maching, as the welding would almost certainly cause some amount of warping. Maybe not much, but here you're chasing accuracy of tenths of a thousandth and it doesn't take much. After welding you'd want to anneal, to take out any internal stresses. Then do your machining.

nheng
07-17-2004, 07:49 AM
If your spindle has a taper which accepts a collet then you have a chance. If your spindle, for instance has a Morse taper, you might be able to find Morse taper collets in that size. Small Emco machines had a funky taper for a precision collet which is now part of history except for ebay.

This gentleman fabricated a closer from a shank:

http://www.lesgrenz.homestead.com/Projects.html

Collets not specifically designed for workholding, such as the Morse taper ones, are a BEAR to get out sometimes due to their long, shallow taper.

You may want to consider building some sort of closer that will hold a 5C collet, depending on the size of your lathe.

Den

sidneyt
07-17-2004, 08:15 AM
It depends on what you define as "cheap". You might want to consider making a closer like I did from a couple of articles that appeared in Home Shop Machinist magazine. Norm Telleson wrote a two part article starting in the May/June issue of 2000 on how to make the collet holder from a MT5-MT4 adapter (these run about $12-15). The rest of the parts consisting of the tube and handwheel cost me less than $25 so the total was $40 or so. You may be able to scrounge the parts for less.

I am making a few assumptions about what kind of lathe you are using. The lathe I own and the one that Norm was dealing with had a MT5 headstock taper with a 1.5" through hole.

Phil Teague

J Tiers
07-17-2004, 08:23 AM
By the time you do that you might as well make a real drawtube one. Should take a couple evenings max.

If you wanted to make a no-tube type similar to the jacobs rubberflex closer, then some of what you describe could be a good approach. But I think a drawtube type would still be more convenient to remove the collet from.

Three parts. Collet closer, fits in taper and holds collet. Drawtube, pulls collet in. Nose protector, does that, and also pushes closer out after use...they get wedged in place.