Milling Issues???

The way I treat those speed and feed charts/formulas is they are set up for very good conditions (machine, cutter, workpiece, etc) and the maximum you can use. I don't run things that high on my machines and I would guess, as a general rule, I use 60-80% of those recommendations.

Especially for import cutters. Even in mild steel I've found when I use a 1/2" HSS import end mill I run it maybe 350-400 RPM for roughing. They just don't hold up like the better cutters.

Ted
 
Guys I did what was suggested,done file test and it did make a scratch.So this afternoon going to give another try but slow the rpm down maybe 200rpm.The 3/8 end mill running at 360 that didn’t work.Maybe for this end mill set need to just go slower than normal.
 
The feed part of this discussion is important as well. Feeding too slow is bad, which is kind of counter-intuitive. You have to feed fast enough that the tool is cutting, feed too slow and it will rub and quickly ruin the cutter. At the microscopic level, the cutting edge of any tool is pretty much rounded, and you have to feed fast enough to get that rounded tool point to go under the material and plow it up, forming a chip. Feed too slow and the rounded edge rides up on it and produces heat and wear. Good luck.
 
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