Sanding a perfect circle on a disk sander

The one I saw was on Woodworks with David Marks

I found this as well. Photos I and J

I had a guide that went on my router. Needed a SMALL 1/8" pilot hole, then set for radius you wanted. Clean up with sander.. Worked like a trammel.

HA HA! Simple as a pimple!

I have done it, so easy it's preposterous. Say the simplest circle cutting jig for use on a band saw:

A nail in a small board.

The side of this board is up against the blade, or the disc. The circle wood the same width from the center, where the nail is.

The nail as well goes into your circle board kinda like a hinge, turn slowly to cut or disc sand. It all must be measured from the nail to the [cutter] to the size wheel you want, again center to [cutter]

The lower board must be larger so it can be clamped down onto the table, I got great results using the same on both machines.

Use a 1/4 pin for your bandsaw, 1/8 for your sander to make sure you get those pesky tooth marks cleaned off. The miter to working surface is a half inch different on mine, so I have to use two jigs.

Reason for this over a router is the uphill problem. If you use a router and trammel, use a spiral bit.