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Sharpening End Mills on a Junked Disk Sander

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vtsteam:
Because of interest elsewhere in the forum, here is a brief description of an end mill sharpener I've been using for several years, built from an old broken tag-sale belt/disk sander.

The start:

vtsteam:
The belt casting was broken but the disk was still good. I cleaned it up and added a new 80 grit disk to try it out (first photo).

I tried it initially for grinding lathe tool bits with a different jig than I ended up with. But then it occurred to me that I could use the existing table slot with a slide to possibly grind end mills. To make that slide I hunted up some small pieces of 1/8" flat bar -- one to fit the slot, and the other (2" wide) to serve as the sliding table. (second photo)

vtsteam:
I have a spot welder that I got a couple years ago from Harbor Freight. After cleaning off the two pieces of metal, I welded them together, and milled the narrow strip to fit the slot in the sander's table. It was a little oversize to start with -- 0.5" while the slot was 0.460". If you were building one like this you could also silver solder them -- or even probably soft solder. There is very little stress on the parts. Or you could mill it out of the solid -- a piece of 1/4" plate.

vtsteam:
I needed some cross pieces to serve as guides on the sliding table. So I spot welded one on at 90 degrees. But the angle needed for end mills isn't 90 degrees so it needed a little modifying.

First step was to blue the slide piece, and mark a line 1-1/2 degrees off square. I decided to do this using a little math since that's a pretty small angle to mark with a protractor.

The cross piece measured 2.10" long, and I wanted to know how far out to make a mark at one end to yield a 1-1/2 degree angle. I figured the tangent function would do it.

With the pocket calculator TAN of 1.5 degrees x 2.1 = .055. So I needed to make a mark .055" in from one end, and then connect it to the other end. This is what it looked like:

vtsteam:
Then I started filing to the line. I could have milled it, but I didn't have a rotary table. And by the time I set up the mill and got that heavy vise over to 1-1/2 degrees, set the cutter height and did edge finding, etc.....well it was a lot quicker and easier to just file it  to the line. I might have spent 5 minutes total.

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