What end mill for brass? Copper?

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Bill Kahn

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I am going to mill about 100 notches into brass. 1/4” end mill. 3/8” full depth (cannot step down bit by bit to the 3/8”). Have to go through a 3/8” piece. (Will be notching out a 3/8 by 3/8 square by 1/4 wide). What end mill would be best? I am guessing a two-flute, like for aluminum but is there something better? Speed isn’t really important—I have a PM25 which does 2500 rpm and am a hobbyist, so I have time. Or, is brass so easy to machine anything will do fine? What might I gain from something like http://www.2linc.com/endmills_aluminum_1fl_std.htm.

I hate working in copper, though the end result can be beautiful. Is there an end mill for the above that will work well with copper without grabbing/chattering/gumming?

Thanks. -Bill
 
I probably do not know your answer, but it will help all of us to know what alloy of brass you are using, if you know what it is.
 
The wisdom of the reference books says to blunt the edges of a standard end mill with a stone, similar to how you would modify a drill bit for brass or plastic. I believe Karl Moltrecht and Harold Hall cover this in the cutter sections of their books. It may even be in the Army technical manual. Anyway, the idea is that you present a square or negative raked cutting edge to soft metals.
 
I would use a new and sharp (not blunted) carbide end mill. Carbide because it’s more rigid and will not flex as much when you make that cut all at once. And choose your lubricant wisely, especially when cutting copper.
 
I agree, do the above (stone edge of HSS EM). I also find liberal amounts of WD40 for coolant work well on copper. Its gummy stuff.

I find brass just plain easy to machine, no special requirements. I do use HSS and hi feeds.
 
I believe the word you are looking for is "sharp".

Clickspring mentions (in one of his videos) that filing of copper and brass require files that are sharper than would be necessary for aluminum and steel.
 
Bob Korves said:
I probably do not know your answer, but it will help all of us to know what alloy of brass you are using, if you know what it is.
Click to expand...
Planning to buy 360, but will be happy to buy something else if it would make a difference.

Would like to use C101, maybe C110 copper, but if like C111 or C182 machines much better I'll look for that.
 
C145 is the best to machine. Mills like brass. Not cheap though.
 
Wow, I was interested in the answers to your question.
Please let us know what you choose and how it works out.
 
pontiac428 said:
The wisdom of the reference books says to blunt the edges of a standard end mill with a stone, similar to how you would modify a drill bit for brass or plastic. I believe Karl Moltrecht and Harold Hall cover this in the cutter sections of their books. It may even be in the Army technical manual. Anyway, the idea is that you present a square or negative raked cutting edge to soft metals.
Click to expand...

I'm not disagreeing with you here but typically, cutting edges on tools used with brass are blunted to prevent the tool from catching or grabbing and pulling the work into the cutter. We have all had this happen with drills. However, I've never seen it happen with an end mill and wonder if you know how Mr. Moltrecht and Hall justify their recommendation. I've milled a fair amount of brass over the years and always used a sharp end mill with no problems but maybe there is something I should know here?
 
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