Damaged endmill?

Ive beeing using a new 274z for a handfull of alumnuim projects and wow, single flutes really make a difference. the first few cut outs ran ok, but after that my cut outs from .064 alum sheet started getting a little rough. I took a good look at the endmill and it looks a little funky to me. Does this look like the endmill has been damaged? Using the speeds and feeds from CC

If that is not a coated bit I would say it has been over heated. The blue usually indicates that the bit got hot. Since it is a solid carbide I dont think it has lost its temper but if it were HSS I would say it lost its temper. Loss of temper means the material is softer. You could try to clean the bit. There are commercial bit cleaners, Some use Easy Off Oven cleaner Lye will also clean bits that have caked aluminum on them (again caution this is bad stuff).

The Lye gives off fumes so use them in a well ventilated area preferably outside. Whichever cleaning method you use wipe the bit dry and make sure you let it dry completely. Nylon brushes will not damage the cutting edges. I would not use steel or even brass brushes.

Take a look at Winston Moys youtube video.

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It’s hard to tell from the picture, but this area (the primary edge you’re cutting with) looks like it’s getting dull. It can be sharpened, if you know how or know someone who does. Otherwise it’s probably time to replace it.


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