Disk Sander

Here's a motorized disk sander for truing up the edges of sides after kerfing. It's a 2' diameter MDF disk that's radiused to 15' on one side and flat on the other, with 80 grit sandpaper on both sides.

The disk has a bronze sleeve bearing in the center, and there's a similar sleeve in a hole in the table top. A lazy susan bearing mounted to a 1/4" masonite board allows for free rotation; the masonite has a 1/2" hole in the middle to keep the lazy susan centered. A 1/2" bolt runs through everything, acting as a shaft for the sleeve bearings.

The motor is bolted to a hinged board which is mounted to a shelf under the table. Since the hinge point is off-center to the motor, the motor's weight causes it to lean into the disk. The hinged board has a support board attached underneath to allow the motor to swing down out of the way when the disk isn't in use. That way I can un-bolt the disk and use the table for other things.

I coated the perimeter of the disk with epoxy so it would wear longer. To make the 2" drive disk for the motor, I ground the flanges off of a 3" pulley and epoxied on a strip of rubber. With the 1 hp motor running at 1720 rpm, the disk rotates at about 130 rpm. I use the flat side to true up the edge of the kerfed sides before gluing them to the top in the mold. I flip the disk over and use the radiused side to true up the perimeter of the body in the mold to accept the back.