Need advice on roughing end mills

Rockytime

Active User
Registered
Joined
Mar 9, 2011
Messages
190
I have never used a roughing end mill. Viewing ebay results in confusion, there are so many. I'm looking for carbide. There are 2, 3, and four flute. Some are listed for aluminum (do they work also on steel)? I have downsized to a Grizzly G0781 mini mill. I work mostly in aluminum and brass and occasionally with 12L14. Projects are usually small and I never use larger than3/8". Any guidance is appreciated.
Regards, Les
 
Generally 2 & 3 flute is what you use for aluminum & soft materials. 4 flute for steels. Also use 2 flute for slotting not matter the material.

The ones listed for aluminum that are actually designed for aluminum (some people on ebay don't list accurate descriptions) have a high helix (usually like 35° & up, please correct me if I'm mistaken) & they work awesome. Usually you'll find these in 3 flute but they are available in 2 flute also.

2 flute was always normally recommended for aluminum but I now use 3 flutes like many others for aluminum when I can. Much better surface finish. There's a video by Stefan Gotteswinter where he shows that he uses regular 3 flute endmills for roughing steel.

Everything posted above is for endmills in general which applies to roughing & non-roughing. For roughing endmills you'll find 2 general different types, fine & coarse... profile, pitch, teeth, not sure of the actual terminology. Fine is better for hard materials, coarse is better for softer materials (mild steels included) & faster material removal. Then there are specialty profile roughers, like Niagara makes some interesting ones.
 
Use a 2 flute for roughing aluminum and 3 or 4 flute for light finish cuts.
Fewer flutes eject chips much better with aluminum. With more flutes, they tend to clog with material resulting in heat build-up and shattered end mills.
Trust me on that, I learned the hard way using a small 4 flute end mill on aluminum. I wasn't pushing it too hard, but the end still shattered off.
 
I normally use coarse pitch roughers for slotting; their larger teeth and the gaps between them clear chips more easily. For profiling cuts I use fine pitch roughers. They seem to cut very fast, require lower power and leave a nicer finish so there is less to clean up.

Almost all my roughers are 4 flute, though I have a few 3 flute cutters. I tend to use HSS most often but cobalt lasts longer, that's for sure. I don't use carbide roughers - they're too fragile and expensive; besides, my mill won't run fast enough to justify them.

I do have some hi-helix HSS roughers for aluminum work. These are 4 flute cutters that slot and profile very well. All of mine are fine pitch and seem to last forever in aluminum. I've been intending to buy some coarse pitch hi-helix roughers to try in aluminum; I should think they will clear chips better. Hi-helix roughers work really, really well on aluminum. If you have not tried them then you're in for a treat. I do not use these on brass or steel - I use regular roughers for those materials.

I would guess most of my cutting is done with roughers. I usually try to save my finishing end mills for finishing up a rough cut; they last longer this way.
 
Last edited:
Thanks for the quick responses. Not sure why I specified carbide as I have never had a carbide end mill. I use HSS 2 flute for slotting and HSS 4 flute for finish. My endmills last a long time as I am very careful with them. I have never, however , had carbide. Mostly I was interested in the roughing mills. I will order HSS in a couple of varieties.
 
Thanks for the quick responses. Not sure why I specified carbide as I have never had a carbide end mill. I use HSS 2 flute for slotting and HSS 4 flute for finish. My endmills last a long time as I am very careful with them. I have never, however , had carbide. Mostly I was interested in the roughing mills. I will order HSS in a couple of varieties.

If you can, take a look at Niagara roughing end mills as Will suggested; they are excellent, as are all Niagara products. I have not seen a 3 flute Hi-helix rougher but I admit I haven't looked. If they make them, I would certainly try them in aluminum.
 
Back
Top