I'm no machinist, but this was a fun build and something worth sharing in case you can't afford a surface grinder or just want a fun project.

It was inspired by something similar I saw kicking around youtube.

Is it precise to the thousandths? No. But it is way more accurate and faster than what I was trying to do before. Took a couple hours to make, and there's a lot of room for improvement if you want to make it better.

Materials:

1.5 inch aluminum square, start with 3 feet and cut to desired length.

10x2x1/8 inch plate

5 1x3/4 inch neodymium magnets

10x2 16 gauge plate

2 10x3/4 inch angle brackets

2 2x1/2 inch round bar for handles

1/2 inch 13 thread rod about 4-6 inches

cabinet hinge. Pick the sturdiest one you can find that will tap into the aluminum bar.

3 1/4 20 bolts to screw the hinge into the aluminum bar

You'll have to do some measuring so it fits under your contact wheel.

To make the magnetic chuck, I clamped the brackets to the aluminum bar, and tack welded the 1/8th inch plate to the brackets. After I made the jig, I ground the 1/8th inch plate flat, then added the magnets and the 16 gauge plate, then ground that plate flat.

So to make it better, mill out the rails after you weld them so they ride on the shaft more precisely. I don't have a mill. Maybe this is just another one of dozen excuses to finally buy a mill. I used an angle grinder to get rid of the corners so it would ride flat. With a mill you could also mill some slots for ball bearings or something to make it ride smoother.

Also a quicker disconnect for the aluminum bar from the table would be good. Right now I just scoot the grinder over a couple inches and flip it up out of the way.

I think it would work better using a harder wheel. This 10 inch wheel I'm using is a little soft, and will round the ends off a little bit if I push the elevation too fast. I'm going to try it with my 2 inch bottom wheel from my flat platen. Also faster belt speed would be nice. Mine only runs at 1800. I think I'm going to upgrade either the drive wheel for more speed or buy a vfd setup at some point anyway.

The build cost was probably under $20 assuming you already have the taps and and other tools.