I'm machining an iron casting, class 30, in my VMC, 3/4" dia mill 4" loc, yes it's long and I can't go bigger in dia as I need a 3/8 radius in the corners.
Niagara end mill HSS TiN, 4.48 fpm, 360 rpm flood coolant. Tech guy at niagara said go higher in rpm so I tried 636 and the mill sings. Problem is I get a wave in the finish, like it's cutting with a end mill that varies in diameter, About 2" down from the top I get a bluge and at 3" down I get a bulge instead of a flat surface.
hold it ...much worse, I went out to measure the bulges and I also have a .050 taper in the last 1/2" at the bottom, how does just the bottom of the mill spring away?
I did several of these by hand on my index mill, now I have 8 pcs so I'm trying to do it CNC.
Carbide end mill? I was using a plain HSS mill before but it has chips in some edges and leaves lines.
Thank You, Randy
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