End Mill Sharpening jigs

OK.....

This sounds like an interesting idea. Would anyone care to share their knowledge on sharpening end mills?

Jerry

I have a cheap import from Enco, and it was not well made. The barrel that rotates the collet has a huge amount of play in it. They depend on the OD of the "plug" that pulls the collet into the barrel to center the back end of the collet. But, the thread inside the plug was not concentric with the OD of the plug! No WAY you can make it work like that.

You could probably buy one of these on eBay for a few bucks, that's all they are worth. Look it over, maybe try it out a few times, and then figure out how to do it right.

But, with end mills being sold so cheaply now, I haven't sharpened an end mill in years.

I also have a ripoff of the Suburban spin fixture. I think you could do most of the sharpening tasks with that with a lot more precision, as you can rotate the end mill exactly 90 or 180 degrees without moving the center or length, as the poorly-made sharpening fixture allows to happen. If you rig a "finger" to the spin fixture, you can also sharpen (or alter) the relief on the SIDE of the cutter. By accident I made some super-hoggers for aluminum doing this. They had about 3 times the normal secondary relief, and you could wail through aluminum at incredible rates. (Normal end mills with

5 degree primary and 15 degree secondary relief tend to rub the back of the flute if you turn up the feedrate too much. There was no way I could turn the cranks fast enough to cause that to happen on these "mistakes". But, it is just too much work to do this unless you have a whole batch of identical end mills (same dia, same helix angle) to do. You can also buy these special mills, but they are expensive.

Jon

It is a lot of trouble. I did figure out how to do this on a milling machine. You need a flaring cup wheel, preferably diamond. I have some atrocious pictures and text here :

about the pics, these are scanned snapshots from a 35 mm camera, done at least 10 years ago. I can't make new pics because I just don't do this anymore. I can get end mills so cheaply now, I'd be wasting my time FAR worse than my USUAL methods of time wasting to sharpen any more. I could use these setups to make special tools, however.

I should note the construction of the diamond flaring cup wheel shown is NOT really the right one for this job, and it is hard to keep the edge sharp. I now have a different wheel that has all the diamond on one face of a plate. It looks like a Baldor diamond wheel, but has a 1" (or maybe 1-1/4") hole for a stub milling arbor. I think this wheel would work a lot better for this purpose, and that's what I would use if I did it again.

If you have any specific questions, I'd be glad to answer them.

Jon

Thanks so far, guys - I have a rotary table, a flare cup wheel, (one friable, one diamond) and could proceed in that direction, but was asking specifically about those odd-shaped blocks which presumably aid in setting the angles corresponding to various reliefs.... My question stands...

cheers / mark

J> Mark wrote:

I have one of those 5C endmill jigs. It does have a little bit of excess play in it but I think I can fix it. With one of those, it's easy to sharpen the end of a common end mill using a surface grinder. No help at all on sharpening the sides. It helps to understand how to sharpen an end mill, and this knowledge isn't particularly easy to come by.

GWE

Mark wrote:

I am by no means any kind of expert on sharpening endmills, but have watched it done quite a few times, but did not pay any particular attention to it as it was something that would always be out of my reach or need due to associated equipment costs and space.

From what I have learned, it basically takes an ain spindle/arbor, and once it has the endmill mounted in the collet, and indexed, its merely pushed into the stone, with a finger following the flutes to rotate it along its helix. Thats for the side grinding of the endmills....Pretty hard to do it and do it correctly without the air spindles.

The ends are ground on a free sliding ..glideing type table after each endmill is indexed for the ends, and fed into a grinding stone, endmill rotated to next edge and slide back into the grinder again...This process is doable on a surface grinder or even on a mill with decent results for touching up or resharpening the ends, but unless you have the air spindle fisture your just spitting in the wind with trying to do any touch up of the sides.

I have always been amazed with the amount of grit and metal grindings on those grinders that do the ends, that they usualy always move with just the slightest touch.....you can practically look at it and make it move. Same for those air spindles.....think move and it moves...

The fellow I know covers all edges he intends to grind with red magic marker as a reference.