I have a 1/2" Kennametal HARVI I TE endmill in a live tool position on an Emco 365MC lathe. I am short on positions/holders in the turret so want to use this endmill to plunge (i.e., drill) the end of a 4140 part before boring an id. Kennametal has a video demo of the tool showing it plunge/drill 4140 at 1.5D (1.5" deep). They give F&S as 590 SFM, 4500 RPM, .002 IPT. (video is here: HARVI™ I TE - The Magic Solid End Mill From Kennametal - YouTube)
My turret live tools max out at 4000 RPM so 0.002 IPT (4 flute) at 4000 rpm is 32 IPM. Which is 0.008" IPR.
I set my F&S to 3000 RPM, 0.006 IPR (thought I was being a little conservative) and plunged in to a depth of 0.25" with coolant on. Seemed to be going ok at the start but about 1/8" in the endmill stalled. I immediately hit reset (stop) backed the EM out and see I broke two flutes off the end of the endmill. Not really sure why this was a problem or what F&S I should be using?
-Tom
My turret live tools max out at 4000 RPM so 0.002 IPT (4 flute) at 4000 rpm is 32 IPM. Which is 0.008" IPR.
I set my F&S to 3000 RPM, 0.006 IPR (thought I was being a little conservative) and plunged in to a depth of 0.25" with coolant on. Seemed to be going ok at the start but about 1/8" in the endmill stalled. I immediately hit reset (stop) backed the EM out and see I broke two flutes off the end of the endmill. Not really sure why this was a problem or what F&S I should be using?
-Tom