02-04-2013, 06:59 AM
(02-03-2013, 06:01 PM)PixMan Wrote: As for 3-flute vs. 2-flute or 4-flute end mills, I use them all. They all have their best applications. In HSS end mills a 2-flute is nice for small diameters (under 1/8") because it can be stronger. Also good in larger diameters for aluminum. I like 3-flute anytime I'm slotting, as they offer the best balance between core strength and chip evacuation. The 3-flute are also the best choice when you need a center-cutting end mill for plunging. Four flute end mills are best for steels and stainless steels, primarily for side cutting (rather than true end milling.) As material hardness goes up, so should the helix angle. Hook, clearance angles, secondary lands, grind quality and raw material quality all play a part in how well your HSS or solid carbide end mill will perform. There are many grades of HSS, and it seems only the very best makers will state the type.
I have some beautiful HSS-PM (powdered metal) 3-flute TiAln-coated end mills for aluminum from Cleveland Tool, and they just kick butt. Those are the ones from right to left, a 3/4" and two 5/8". I have a few solid carbide that I wouldn't be without, and many in between. Buy quality tools and treat them as such. You'll be rewarded with good parts and fun making them.
Wow! That's a lot of great information. Thanks for taking the time to post it. I certainly learned a thing or two. I did not know that a 2-flute end mill is stronger than a 4-flute in smaller diameters but it does make sense.
Ed