Collets and concentricity

OK I will get some
I did do a build on this site but am unable to find it now.
 
Thanks Brino I thought there was more as well.
and heres the pin spanner for it
post 9832
and the wrench for the nut
er spanner.jpg
Dont forget I only made the chuck, I purchased all the collets, nut and special wrench.
 
I use an ER40 chuck for fine work. Before I clamp, I check for concentricity. Subsequent to mounting the chuck I indicate the taper inside, making sure it's as near zero as I can get it (Set True Chuck). after I've tightened the work I check it, usually it within .0005 to .001, but I bump it around to nearest zero I can get it. Then I re-tighten the chuck and check the part again.

It's tedious, but I get finished parts routinely under .001. When making tooling, this is ideal.

Edit; Correct automatic correction.
 
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To add to everything above...

My South Bend 14 1/2 lathe has 3 chucks, a 9 inch 3 jaw, a 10 inch 3 jaw, and a 12 inch 4 jaw. Because of the flats on the inside of the jaws, the smallest diameter I can hold is about 7/16 inch. I bought a 5C collet chuck for it and a set of collets... this allows me to hold pieces down to 1/16 inch easily.

My 12 inch Hendey lathe has a 10 inch 4 jaw chuck... I have the same problem with it. The jaws, when closed until they are all touching, leaves a hole in the center of about 7/16 inch. The Hendey has a very short bed... I think I may be able to get about 15 inches between centers. The 4 jaw chuck takes about 6 inches away from that. Because of this, I am considering an ER type collet chuck for it, which would only take 3 inches or so of my usable length.

-Bear
 
One of the reasons that I bought a 5C collet chuck was the increased clearance when approaching work from the chuck side. My ball turner couldn't get close enough with my three jaw to turn a complete ball unless I had an excessive stick-out.
 
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