I think a pair is gashes at 45 degrees to the cutting edges through the centre is the quick and easy solution with a saucer wheel if you have one- the centre portion has virtually no cutting effect anyway… while this may affect the aesthetic of the cutter, does it have a negative effect on the cutting action?

I find that once 'gashed' the cutter can be touched up several times before needing hashing again..

Hi Clive,

You have, of course, checked Harold's website? I don't know if these may be of some help: link1 , link2. They are not using the Quorn, but should give some guidance. When I sharpen the centre cutting edges of end mills I do that much the same way as slot drills.

Thor

RichardN,

Purpose of the over centre teeth is to permit plunge cutting (normally done with a slot drill), You cannot do that with a normal end mill.

Horses for courses.

Hi

Don't get mixed up with slot drills and end mills:- slot drills you can plunge cut and usually have two or three flutes, end mills are for cutting horizontally, the four flute jobs that cut across centre are a bit of a mix between the two personally I wouldn't use them as a slot drill

I've reground all these cutters the two on the left are slot drills the four flute on the right is milling cutter, the two slot drill I re-cut the gash with a hand held dremell I gashed the end mill on my home brew cutter grinder you can see I've reground it quite a few times and the original centre hole has gone.

This is how I gashed it

And sharpended the face

And proof of the pudding EN8 milled on my X3

Stew

The sharpeners such as the EMG-12 that ARC sell do the gash cuts as part of the sharpening process but leave one flute long so you can still plunge or ramp in with the cutter.

Correct, but it's normal to ramp or follow a helix instead of plunging. That way the centre isn't trying to cut at zero feedrate. When using a ramp or helix I normally reduce the feedrate to about half to account for the fact that only some of the teeth are cutting at the centre, and for the full length of cut on the bottom edges. Something that doesn't happen in normal constant depth milling.

Andrew

Ok

Her's the picture you can see that the cutter has been well used with the edges chipped but you can see the centre cutting configuration.

Stew

Stew: I'd hazard a guess that the cutter shown is keenly priced far eastern? It's not clear how the edges meet in the centre. This is what I would expect from professional cutters:

Of course, when all is said and done the cutters are intended to cut mostly on the sides, not on the ends.

Andrew

I sharpen those end mills on my Clarkson grinder by holding them in a R8 collet and using a simple index wheel on the back. It works very well indeed.

There is always one that has to state the bleeding obvious