Method One:

On your lathe, turn a piece of maple or oak into a disk to the size you want. Mine is 5" and a smaller version is 3". Leave the topside slightly convex and on the crown of it turn a recess the size of the outer diameter of your bearing and slightly less deep than the thickness of your bearing. After that's done, continue with a smaller hole straight on through the disk. The size of this hole should just big enough so you can use a socket wrench on the head of the bolt assembly together. The bolt you will use should fit nice and snug through the hole in the bearing you are using.

Using epoxy, glue the bearing into the hole you made for it. Be careful - you want the inner race of the bearing to run free, so keep the glue restricted to the outside diameter of the bearing. Also, rough up the outer rim of the bearing on your grinder to give the epoxy a good gluing surface.

The handle is next, and it can be any shape you want. A hole the size of the nut (or the socket you'll use) on the bolt is drilled part way into the handle. Use a Forstner bit so the bottom of the hole is flat. Then continue with a smaller hole, the diameter of your bolt, right on through the rest of the handle.

Here's how you put it together. Put a washer on the bolt and run it through the disk from the bottom and through the hole in the bearing. If you have made the disk thick enough, (mine is about ¾”) the head of the bolt will be below the surface of the disk where the sandpaper goes. Put another washer on the bolt on top of the bearing.

Then the handle goes on to the bolt, another washer and finally, the nut. You will have to calculate the depth of the holes according to the bolt you use. Using a socket on the head of the bolt and a socket on the nut, tighten the whole mess up.

The disk should turn freely, because the inner ring of the bearing is trapped between the washers and the disk is only attached to the outer ring of the bearing.

Using either epoxy, silicone glue or contact cement, glue strips of the hook side of Velcro over the disk. Don't cover the hole where the bolt is, 'cause you might want to take this apart again. The Velcro comes from the fabric store. I got it in 1" strips and just cut it to fit with scissors. The Velcro I put on 7 years ago is still going strong.

Method Two:

There's an alternative method I thought of, but haven't tried. Here it is, and if you try it and it works, let me know.

Again, turn your disk to the size you want. One side (A) is flat, or perhaps slightly convex. On the other side (B) leave the center of the disk a little higher; say a convex shape with the center 1/2" higher than the outside edges. Turn a hole in the center of side (B) to the thickness of the bearing you are using and the outside diameter of the bearing. It should fit nicely into the hole.

Now turn the handle. Leave a stub on the bottom of the handle to fit into the inner hole of the bearing.

Rough up the gluing surfaces of the bearings with a file or grinder to give the epoxy a bonding surface. Then glue the stub of the handle into the center of the bearing and after that sets, glue the outside of the bearing into the hole in your disk. Again, use a hard wood like oak or maple.

This is a lot simpler than the other way, and I can see no reason why it wouldn't work. However, it probably won't take the beating the other ones will.

To use these sanders, just slap on a hook and loop-sanding disk and hold the pad against the work as it spins. A little practice is all it takes. It works so well I actually use it to do subtle re-shaping on a piece if I have a problem with the design.

Method Three:

This is the most recent passive sander. Again, the simple principle is that the inner ring of the bearing is trapped between two nuts on the shaft. The outer ring of the bearing is fixed (glued) into the disk part of the sander.

As you can see, I made the new one simpler by just using a threaded rod. This one happens to be bent, but a straight one would work the same. The shaft of the threaded rod just gets glued into a handle. The size of the holes is simple. The one on the top of the disk has to be the size of the outer bearing diameter and as deep as the bearing is thick. The other hole that goes right through the disk is the same size as the outer dimension of the socket wrench you'll use to tighten the nut.

To put it together, turn a nut onto the threaded rod. Slide on the bearing that has now been glued into the wooden disk. Then thread on another nut and trap the bearing. (You may want to use a flat washer on either side of the bearing). To tighten in, use a socket wrench on nut on the Velcro side of the sanding disk and an ordinary flat wrench on the other nut.

If you've made the disk a little thin and the nut sticks up above the surface of the disk, just cut the nut in half with a hacksaw and make it thinner, or grind it down.

Glue on your handle and you're done.