Newbie question - End Mill Selection

[evena4]

I have gotten the metal machining bug and after acquiring a Mill and using it for various projects, I have some questions about roughing end mills.

I have just started to figure out how handy they are for quick clearing of the aluminum scraps I am playing with. The roughing end mills come in 30 / 45 / 60 degree helix formation and I am wondering what the difference is.

I live near Seattle and can buy used (sometimes slightly) endmills 2 flute, 4 flute and roughing from the Boeing Surplus Tool Crib. They run from about $2 for 1/2" and under to about $15 for a good sized 2" or better. I want to know how to get the most use out of them.

I pretty much am working with aluminum (6061) and I do not use coolant with my mill (yet) and want to know how to figure out how much material can be removed by a roughing tool and what the importance of the helix angle is. Does it affect the cutting speed, the finish which shouldn't be important on a rough cut, right or tool life?

Any help is appreciated,
Thanks,
-Manny

[BMackinnon]

If you are manily working with Alum. I would say two flute to eliminate rubbing cutting edges and to increase chip evacution. Four flute will rub causing wear and will gum/clog up easier, even more since your not using coolant.

I did a quick search and came up with this for helix angles:
http://www.manufacturingcenter.com/t...ing_around.asp

But for your best results I would look up the manufacturers callout for each tool.

HTH

[evena4]

Bmackinnon, thanks that link is what I was looking for.... should get me off to a good start. I will also check the manufacturer's specs.


-Manny