End Mill Grinding Fixture review

[churchjw]

Since I got my surface grinder up and running I purchased the Enco "End Mill Grinding Fixture" http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=949927&PMAKA=287-6840 With discount code and free shipping is was about $40. I already had a set of the 5C collets.

Over all the finish is good. The markings on the collar are laser etched into the part and hard to read when being used. I ended up marking the 4 positions for grinding a four flute end mill with a sharpie so I could see them.



Here it is on the grinder in the two positions for cutting the two angles for each flute. The thumb screw on the end locks the rotating collar into position. Its sometimes hard to get it to lock it into the right location. There is a small ball that sits in front of the thumb screw that should fall into the hole on the collar to indicate the position but I found you had to turn the collar back and forth to find the hole or it would lock in any position. There is no indicator line on the block to line up the collar marks. After a few end mills you get the feel of positioning it.

The block not only has the main two angles it is also tipped sightly to one side. This adds a clearance angle on the leading edge of he cutter. This also means you have to grind with the wheel on the flute closest to the operator. The first grind I made was on the flute on the back side and was all wrong. :banghead::banghead:

I was a little concerned with the small amount of metal touching the mag chuck when cutting the relief angle but so far it held just fine.

A big issue I had with the fixture is with the collet nut. This is the nut that tightens the 5C collets.



As shipped the nut uses two pins and a pin spanner to tighten. However, the nut when on the fixture is down in a hole. :nuts::nuts: You can remove the collar from the block and then tighten the collet but this makes lining up the end mill flutes very hard to do and I kept dropping the little alignment ball. I could not figure out how to do it. Maybe I am just missing something here.



So I cut a slot in the other side of the nut and made my own spanner wrench.



You can see the nut here down in the hole.



Now I just put the block on a flat surface "relatively flat", use a square to align the flutes, and then snug the nut down.



Here is about two hours of work. I got much faster as I went. A bad one takes about 5 min now. I got a box of these from .500" to 2.000" from a friend. He got them in an auction box lot with some stuff he wanted. Most of the flutes are really chewed up. He gave them to me so I could practice grinding. So far they all cut great as long as you don't try to cut to deep.



I am not going to put any pro sharpeners out of work but I am pleased so far with my results.

So far I have been very pleased with the tool.

Jeff

 

[4GSR]

Looks nice so far, Can I send you my twenty lbs of end mills to sharpen?:biggrin:

I can't wait to get my SG running to try what you are doing too.

 

[Hawkeye]

I like your custom wrench. Much better than their method.

I'm a bit concerned with the position of the fixture relative to the curve of the wheel. It looks to me like it would cut the primary angle downhill. I would expect that the edge being sharpened should be directly below the centre of the wheel shaft. The picture of the finished end mill doesn't calm my apprehensions. Have you tried cutting with it yet?

 

[churchjw]

I like your custom wrench. Much better than their method.

I'm a bit concerned with the position of the fixture relative to the curve of the wheel. It looks to me like it would cut the primary angle downhill. I would expect that the edge being sharpened should be directly below the centre of the wheel shaft. The picture of the finished end mill doesn't calm my apprehensions. Have you tried cutting with it yet?

I think I understand your question. Sorry very new to the grinder so I hope I am answering the right question with a good answer if not maybe someone with more experience can help us both understand it. First the pictures are staged after the fact but the set up was the same as I was using. Was mainly trying to show the position of the fixture. The wheel moves fully across the flute when grinding so the (you move the table length wise all the way across the tooth.) cutting edge it makes is dead flat to the travel of the wheel. The fixture set the angle of the flat. If you look at the second picture the flute with the big chip out of it is the one being cut. The wheel moves completely over and past the bit cutting the angle flat to the chuck/table. Does that make since. I tried a few of the bits and they seam to cut great.

Jeff

 

[Hawkeye]

Thanks, Jeff. That clears that up.

 

[jgedde]

Those end mill fixtures aren't half bad! I have one and it was worth every penny. I have the Eagle Rock version which uses an Allen bolt for collet tightening. http://www.amazon.com/Eagle-A1-20500-WEM-99-Grinding-Fixture/dp/B0006567Z6

I haven't figured out if I can sharpen end mills to be center cutting or not, but I have sucessfully sharpened a number of gashed mills.

Be really careful grinding the secondary relief as there isn't much meat holding the fixture to the chuck. I've had it move screwing up the end mill, the grinding wheel and dinging the chuck. I now block the fixture in and put a piece of masonite on my chuck to the left of the fixture to protect it in case the fixture comes loose.

John

 

[xalky]

I got one of those fixtures from a bulk purchase of tooling I had made last year. I wasn't sure how it was used. Now I know. I also bought a magnetic vice in that lot of tooling. But I don't have a surface grinder or 5c collets. Maybe I could rig up a grinder attachment for my mill?