Machining copper

HI

Can anyone advise on machining copper. I am working on a boiler and I have trim some plates in the lathe, would I use the same shape of tool as for machining brass?

I also have to drill a large number of holes, what would be the best drill bit shape. Should I modify the drill bits as if I was drilling brass?

I obviously don't want to 'tear' or otherwise damage my prepared copper plates/barrel.

Thanks in advance.

Trefor

A tool with more top rake will work better like you would use on aluminium or a **GT insert if you prefer inserts.

For larger holes to take bosses and firetubes I would go with a step drill and have never bothered to alter smaller twist drills for brass, bronze or copper.

Full fat milk makes a good cutting fluid.

As a full time copper boiler maker I do quite a bit of this.....I only ever use CCGT tips (as per JB) for turning copper as they out perform everything else by a country mile - no grabbing and clean cuts. Standard drills are fine but beware that your holes will all come out slightly under size. You need to lubricate when drilling copper, and it gives a better cut when turning, I use wd40 as it does the whole machind good and doesnt smell bad. Good luck!

Lots of rake. Definitely not zero or negative rake as for Brass.

Drilling holes, twist drills ground to a brad point wood bit form work well. The sort with a central triangular bit in the middle and the corners proud so they start cutting before the flanks. This gives a clean hole with no burr on the reverse side.

regards Martin

It's always a good idea to try the recommended tooling on any offcuts of the metal first to get a feel for yourself. That way there will be no danger of spoiling the actual workpiece.

Thanks everybody for your replies. I'm going down to the workshop now to do some tests/practice on some scrap copper.

Thanks again

Trefor