So a little while back i mounted a teknomotor 1hp 24000rpm spindle to my nm145. the mounting is a bit weak, I just bolted it to the side of the head with 2 m6 screws. The spindle body is aluminium so it does vibrate on heavy cuts or tools with major overhang, but its working phenominally well. I've used it mostly for wood, but also a lot of aluminium.

Here's a video of it in action making some cute kittens from hardwood:




That's slotting, 30ipm, 1/8" cutter, 3/8" depth in an unknown super hard south american wood.

I've got some metal kittens to cut. Not sure how well that will go yet.