The old craftsman drill presses had an optional third drive pulley that mounted in the top of the column between the motor and the spindle, called the slo-speed option, that allowed a greater range of RPMs for the drill, including letting it go below 200 RPM, which it great for drilling and milling larger holes in steel. The slo-speed options are very hard to come by and expensive when you can find one, so I made my own. This weekend I finished up my slo-speed option and got it up and running.
I turned a piece of 6061 aluminum on the lathe to make the body, and then bored it for an axel and bearings. I found a new four ratio pulley for 1/2" belts that has the same 2", 3", 4", and 5" steps as the stock pulleys (needed to keep the same belt length as you swap ratios). I put it all together and used new link belts. It works great. So now I'm pretty much done with my drill project and just get to enjoy using it and looking at it.
I turned a piece of 6061 aluminum on the lathe to make the body, and then bored it for an axel and bearings. I found a new four ratio pulley for 1/2" belts that has the same 2", 3", 4", and 5" steps as the stock pulleys (needed to keep the same belt length as you swap ratios). I put it all together and used new link belts. It works great. So now I'm pretty much done with my drill project and just get to enjoy using it and looking at it.