turning copper

Peter Fairbrother wrote in news:BE718731.97B10% snipped-for-privacy@zen.co.uk:

Try a pcd (diamond) insert.

Use a constant flood of any kind of coolant/lubricant or it will gum up.

Guy Lautard recommended *milk*.... I've tried it, and it works nice. Ken.

I turn a fair bit of copper to make electrodes for EDM...

I always use HSS, very sharp, 0 rake angle, mist set so heavy its almost flood. Hi speed, low feed.

Karl

So how do you know this Guy Lautard fellow - I have a copy of his=20 Bedside reader here... Is that where you saw it?

--=20 Will R. Jewel Boxes and Wood Art

power of accurate observation is commonly called cynicism by those=20 who have not got it.=94 George Bernard Shaw

Whole or skim? Seriously--could make a diff!

Didn't someone around here once suggest freezing copper before turning it?? To stave off work hardening? Seemed like a neat idear.

possible. I'm

Like the other guy said, 0 degrees rake, basically a flat top tool. Any positive rake will hog in, as you've found out. I've turned a lot of commutators and usually take off about .005" at the most with that interrupted cut. I haven't had to use any coolant. I use HSS and use a diamond hone on the tool to polish before using it. Feed slowly and don't get in a hurry and the finish comes out just fine. A round-nose tool helps, too. Make sure it's dead on center, too high or low is as bad as having rake.

If you've got bucks and need the finest finish, use a diamond. I saw a picture of a copper drum that was turned with a diamond for some special optical purpose, looked like a mirror.

The only heat-treat possible with copper is to anneal it.

Stan

Yup - one of the bedside readers..... I've got 'em all and just keep re-reading them over and over - maybe because I enjoy them or maybe because it just doesn't sink in :-) Ken.

Use d-limonene for cutting fluid. Works a treat for copper and aluminum alloys. Any of the more concentrated citrus cleaners will work if you can't find the pure stuff.

I recently turned a commutator using it. I've turned many comutators over the years and have never had one come out as nice as that one.

Ted

Yesss!

I used:

sharp tool steel (HSS+) but no diamond honing, zero rake no breaker (_actually_ a flat top tool, I just polished up a 15 degree clearance blank on a fine wheel)

dead on center, fast speed, slow feed, small cut

milk (didn't have any d-limonene) fed on a soft paintbrush to limit mess and smell when it goes off, the prospect of a suds tank full of rancid milk didn't appeal

and it works great - lovely surface finish, like a mirror, very little force used ...

... and no hoggin, so I feel confident to turn the expensive (they aren't actually expensive, but they have had a lot of work done on them) work pieces.

Perhaps a little slow for quantity production, but perfect for my purposes.

Thanks very much all.

Did a bit of work on those books. :-)

The software wasn't really up to it when he did the first book -- but it =

got better and so did he.

=2E..another lifetime I guess. His buddy Jack introduced us.

--=20 Will R. Jewel Boxes and Wood Art

power of accurate observation is commonly called cynicism by those=20 who have not got it.=94 George Bernard Shaw

Great books just to have around for "enjoyment" reading... been through mine dozens of times and it seems I learn more each time. Well worth the bucks spent - for entertainment value alone :-) Ken.