"Roy" wrote in message
...
I am in the process of making an item for my sal****er setups, and
have to thread the inside diam of a 3" socket joint (happens to be
correct bore needed for my application and only needs threads) which
are 13 tpi. My biggest problem is if I tighten the piece up in the
chuck it distorts it. I ruined a bunch of pieces trying to find a
sweet spot n chucking prressure with out distortin oor without having
it slip. Even with light cuts its gone wrong. Perhaps I need to put it
all away and give it a try on anaother day, unless someone can suggest
something that may work to hold this piece in the chuck without
distortion or slipping. I have played with super glueiing it, double
faced tapes, but one thing I have not tried net is to glue two or
three lugs on the outside of the piece I am turning and allow them to
hold against the chuck jaws sides.........hmmmmmmmthat idea just hit
me, is there anything else that may work?

PVC is neat to machine, but it can get awfull flimsey and such when
chucked up.....

Roy,
This is an excellent place for soft jaws. If you make some jaws that are
broad enough, they'll enclose the piece almost totally, eliminating
distortion. It's worth the effort, for then you'll have the jaws for other
applications, and you'll be surprised at how often you'll use them once you
have them. Nice part is you'll be able to take the piece out and put it
back and have it run nearly perfectly. The advantages of soft jaws are
almost endless.

Harold