5C end mill sharpening fixture?

Question

Having relinquished my tool & cutter grinder, I'm now again thinking about how to sharpen end mills - just touch them up on the end. I know for sure you can't do as good a job but I'm thinking about part no. 287-6840 here:

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I've seen these before, but that was before I knew how to sharpen an end mill. I have a question for someone who has one of these: there are 3 angles to worry about sharpening the end of a fluted end mill. The first angle is the primary relief angle; the second is the secondary relief angle. I'm sure this fixture will handle those correctly. The other one is the so-called "fishtail" angle of maybe 1° on the very end of an end mill. If you haven't noticed it, if you hold a new end mill down against a piece of plate glass and look under a strong light with magnification you will see that the tips of the flutes touch but that the centers don't. This is the "fishtail angle". I want to know if this fixture (or similar) handles this angle correctly.

Thanks,

Grant Erwin

Steve Steven · Accepted Answer

Grant,I have a cheap Chinese-made end mill holder/sharpener like the one you are talking about, and it does have a "fishtail" angle built into it.  Mine is designed to work with 5C collets as holders, indexes about 12 points IIRC.Steve Steven

Karl Townsend · Answer

GrantBefore I got my Monoset T&C grinder I used one of these all the time. The trick to getting fishtail is to put the endmill in so the you set the unit at an angle on the grinder table , not square to the line of trave. Then part of your land angle goes to giving primary relief and part of it gives the fishtail relief.  IIRC, setting the unit about 30 degrees off the line gives 1 or 1 1/2  degrees fishtail.Karl

G.Tom · Answer

Hi Steve ,What is this sharpener and where is it sold?Thanks for any help.Tom Munroe"

Randal O'Brian · Answer

I have one.  The fishtail angle is built into the fixture and all you needto do is to align the base parallel with the grinder travel.Randy

5C end mill sharpening fixture?

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