DIYbanter - View Single Post

(Ed) wrote in message . com...
I'm considering purchasing a 5C collet chuck for my lathe. I'm
currently using 3 & 4 jaw chucks and want the added accuracy of 5C
collets. Having no experience with 5C collets, can someone tell me if
they will hold my work: I work a lot with bar stock in the range of
0.7" to 1" diameter, in pre-cut lengths of 0.120" to 0.5". I need to
bore these pre-drilled pieces to ID's ranging from 0.5" to 0.8". This
is not production work - I can't build a specialized fixture or modify
a collet for each piece.

I plan to have 5C collets in 1/64" sizes for my OD range. Will
standard 5C collets hold my work for boring? What I mean is, I don't
want to bore a step in the collets (I'm not doing production work) to
hold the piece a fixed depth in the collet. I'd like to have some
sort of internal collet stop that still allows the 3/8" boring bar to
pass through the center. Any help is appreciated.

Regards,
Ed Ferguson

If I understand your question, the solution is to buy a standard
Hardinge style collet stop (screws into back of collet) and make your
own stop rods which are hollow for boring bar clearance. Hardinge
uses 1/2-20 threaded stop rods so you'll need ones with a bigger head
on the "stop" end. Over the years I've had the same situation you're
in and accumulated a whole bunch of home-made stops of various end
diameters.

Here's a hint to same some machining...buy those cheapo adaptors used
to mount grinding wheels on motor shafts. Most have a 1/2-20 thread
with a hollow big end to slip over the motor shaft. A couple bucks or
so. Machine the big end to suit your job.