Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

You can kinda see the 2-56 tap in the groove in the images above, I just hold the tap in my drill, get it spinning, then drop it into the pulley groove. If you hold the drill still and don't let it pull forward, it will pull itself along in the pulley groove, and you can do as many laps of the pulley as you wish. Mine took about 3 laps on the steel pulley, 2 on the brass. I can't tell where the thread overlaps, but I assume depending on the diameter that it won't line up perfect. I have never noticed anything bad, but these are also 56 tpi, so it's pretty darn fine and probably just jumps to the next tooth! I have used this technique on many engines and accessories to increase traction, as I use the wilesco spring belts and they slide without something like this to grip. I can make a video if you think it would be helpful to see.