I searched all over for how to get more RPMs from the PM-25. Lots of options, but I took the simple approach (Maybe simple should be in air quotes?) and made a larger pulley for the motor, a new motor mount that provided space for the larger pulley, and got an appropriate size belt for it.

The existing motor mount doesn't have room for a larger pulley, but a new motor mount can be built to handle any size pulley you desire. I was shooting for about 120mm pulley but by the time I turned it down on my lathe and mill-turned it on the PM-25 itself, I ended up a little smaller. Oh well. So 4700 RPM instead of 5000. NO big deal.

Most of my stuff involves smaller end mills with 6mm being about the largest I regularly use. The difference between 2500 and 4700 for my 4 to 6mm end mills is like difference between night and day. It's making me crave a 10,000rpm SYIL or Tormach, but it'll be a little while before I justify that.\

I did my modeling in Fusion 360, and while it's not perfect it works for me. If anyone is interested, I can provide some pictures, the F3D (Fusion) files, and a link to the size belt I used.