|I used this plastic stock for my pads. You can use any insulator. I have used wood but I used an insert in the wood so I could have threads that wouldn't wear out to quickly.
|I didn't do any measuring I just cut a piece and used it to size the next piece.
|The tube is a sink supply. You can use a plastic pipe. I like the sink drain because the slug fits snugly in it.
Another version of variable inductor