On Fri, 23 Dec 2011 10:28:50 -0500, Randy333
wrote:

Any here have some real experience machining bronze castings? I have
to do a job with a 4"deep bore 1.750 dia. and a 32 finish. Can I do
it with a long carbide end mill? I use 4" LOC hanita vari-mills in
cast iron and they leave a really sweet looking finish when they are
new. (when they get dull the start to chatter).

Or is this boring head territory? I have a tooling guy quoting me
some boring heads.

Remove 333 to reply.
Randy

As Ed said, a lot depends on the alloy. I used to be in the marine
hardware business and have machined a lot (1) of 85-5-5-5 and
manganese bronze castings. We used round inserts for most of the work
on the 85-5-5-5 castings -- stuffing boxes, stern bearings, etc., and
though we had no specific finish requirement, I'm going to guess it
was in the 32 neighborhood.

The manganese bronze was tougher, and less tolerant of large tool
radii on a long tool.

(1) Enough that after a day of running stuffing boxes on the J&L
turret lathe I'd have what felt like a pound of bronze chips my pants
pockets.

--
Ned Simmons