Adjuster Knob for MicroMark Drum Sander
I have a MicroLux Drum Sander which is a nice little tool for sanding things that are too small to go through the planer. The only problem I’ve had with it so far is that the height adjuster, for the table that wood goes through the sander on, is hard to adjust by hand.
So I had a thought the other day, and decided to make a knob for it. I started with a chunk of hard maple, and cut a 4 inch square by ⅜ inch thick piece. I found the center by drawing the two diagonals, then drew a circle on it. Where the circle crossed the diagonal, I used an inch and a half Forstner bit to take off the corners.
That done, I drilled a ½ inch hole through the center and chucked it up on the lathe. Used a parting tool to make it round, and then sanded a bit to clean up the rough edges. Then I popped a ⅜-16 bolt through that center hole, got it as centered as I could by hand, and drew lines to make a hexagon around the hole.
The nice thing about a 9/16 inch hexagon is that a ⅜ inch chisel is almost the exact length of a side of the hexagon. And the ⅜-16 bolt (and nut) have a 9/16 inch head. When I put my (inch) calipers on the bolt-head in the sander, it told me 35/64 inch, which is close enough that a 9/16 will work.
After a short bit of chopping with the chisel, the bolt fit through the hex hole I had cut.
Next I made the hole a hair larger on one side with a ⅝ inch spoon bit, going about an eighth deep, and cut a short bit (also about an eighth) off the end of a ⅝ inch brass bar I had on hand (which has a hole drilled in the end from when I was making nuts a while back) and put them together.
With that done, I gave it a test. Here it is on the adjuster bolt. You can see that the brass is slightly proud of the wood surface, so it will serve as a bearing. I meant to do that!
And with the table set down, it’s now super-easy to adjust the height of the table. I think the bolt is a M6-1 which means every rotation gives me 1 mm up or down. On hard maple, one eighth of a rotation was plenty to lift the table for every pass through the sander, but I’m not sure how much of a change that is where the sanding drum contacts the wood.
Tomorrow, I’ll pull my new knob out of the sander and epoxy the brass into the maple with as little epoxy as possible. I’ll probably give it a coat of oil too. But in about an hour, I had fashioned a new knob, and I’m much happier with my little drum sander now. Yay!
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