Newsgroups: rec.crafts.metalworking
Subject: Re: Advice wanted in machining lead 
From: Doug White <gwhite@ll.mit.edu>
Date: Thu, 17 Mar 94 16:12:18 -0500

In article <pazcw-100394123957@ppacwz.nottingham.ac.uk>,
pazcw@uk.ac.nott.unicorn (Clive Washington) writes:
|> I'd like some advice as to the best way of machining soft metals
|> like lead.

This may not be practical in many situations, and I've never tried it on
lead, but freezing might help.  I knew a machinist who used to turn things
out of rubber (!) by freezing them with liquid nitrogen.  This made the
stuff hard enough to cut with some (?) precision.  He had to be very careful
to keep his cutting tools extra sharp to avoid heating things back up.
The tools were ground with a LOT of rake angle to work much more like a
knife than a conventional tool.  I haven't tried rubber, but I have had
some improvement in finish on soft plastics by cooling them with the 
spray freeze aerosol used for testing electronics.