I have a Weiss VM25L (essentially same as G0704) CNC conversion that supposedly has an 1100w/1.5HP motor. I currently use Hoss' belt drive for ~5k rpm with a 1.2:1 timing ratio. Even with the stock belt drive that did 2250 rpm, I could hear the motor doing some heavy work to keep up. I just doubt it has much for torque at the top end, but that's kind of ridiculous considering it's supposed to be a 1.5HP motor. With the pulleys it's even worse, understandably, and I believe it's causing chatter during cuts. Was doing tests yesterday with an indexable 1 flute 1/2 endmill and even in relatively light cuts in aluminum it has terrible surface finish and the rpms bog down. I see some older posts about new motor upgrades where people are taking pretty hefty cuts even with something like a 3/8 endmill. I doubt it's a rigidity issue since some people are taking such heavy cuts with great surface finishes.
So I'm looking at different motors but the main problem is most seem to be 220v 3ph motors. I only have access to 110v single phase in my garage with my mill so I'm not sure what I should be looking for. I use a Masso control board and it would be nice if I could use a 1:1 pulley ratio with that to automate the spindle but that's not necessarily critical. I'd like at least 5000rpm and at least 1HP as long as the torque is well off enough at the high end of the band that I can take some beefier cuts with decent finishes. If possible I'd also like to avoid a VFD/Chinese router spindle. Dealt with these in the past on my router and it was just no fun.