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Endmill
03-22-2005, 10:05 PM
I am curious whether brass can be readily cut with an unhardened steel tool. I was thinking of making some lathe forming cutters with a radius of 1/4 to 1/2 in out of some steel plate by drilling a hole and then cutting half away. Lifetime is not much of an issue as only a few brass parts would be made, And NO I AM NOT MAKING PARTS FOR A BRASS MONKEY !.

precisionworks
03-22-2005, 10:22 PM
Depends, could be 1/4 hard, 1/2 hard, hard or extra-hard. Brinell hardness can vary from 50 to 150, depending on alloy.

C36000 Free Cutting Brass is the easiest to work & has a machinability index of 100.

C86500 High Strength Yellow Brass is much stronger, much harder (130HBn) and has an index of 26.

Mike Burdick
03-23-2005, 12:20 AM
Don’t mean to be sarcastic here but why don’t you try it?

wierdscience
03-23-2005, 08:24 AM
Make your tool,then get a can of Kasenite and case harden the mild steel tool,should work fine.

SGW
03-23-2005, 09:31 AM
Places like MSC sell pre-hardened 4142 ground stock, that might work for this. It machines pretty well -- you don't need special tooling to machine it -- but it would certainly stand up better than generic "mild steel" as a brass-cutting tool.

Endmill
03-23-2005, 08:12 PM
I got part of the answer I was looking for, the Brinnel Hardness. I was re-reading an older machine tool book, and it set relative hardness as the first criteria for a cutter. If this and geometry alone suffice, then one should then be able to cut softer materials such as aluminum and brass with about anything.

One of the old standard jokes was to replace a lathe tool with a piece of keystock.) Theoretically, if shaped properly, it should cut brass and aluminum quite well.

Also Somewhere I have some relatively pure antimony metal, which according to memory is quite hard, i.e. could not be scratched with a file. It melts at a low temperature and this suggests the possibility of casting a formed cutter shape.

The answer is obviously to do some experiments.
Thanks, Bob

Boomer
03-23-2005, 09:26 PM
If you're only making a few you could use Marvs Ballcut utility...

http://www.geocities.com/mklotz.geo/#shop

This is an elongated ball made from 1.5" 360 brass rod...

http://img.photobucket.com/albums/v324/46boomer/Ballcut1.jpg

http://img.photobucket.com/albums/v324/46boomer/Ballcut2.jpg

Don't think I'd try it without a DRO though.

Bruce
P.S. Thanks Marv