Hi,
when I read the spec of the BCH2.F I saw a continuous torque of 2.39Nm which is slightly more than the SEM's you are replacing.
That's plenty.....you will never even get close to absorbing the power that servo can produce....underpowered!
Remember also that power is torque times speed. Even without changing the gearing the BCH2.F will have more power right throughout its
rev range up to 3000 rpm, thereafter the SEM nudges ahead. Will you ever get close to 3000 rpm? 1:1 on 5mm pitch screws is 15m/min,
so not even close.
We have a customer who has an oldish twin column Okuma CNC, its freaking GINORMUS, and its Y axis motor is 1hp. It lunks around the
main spindle which is 50hp and weighs 1/2 a ton or more.
A 1hp axis motor will drive your lathe within an inch of its life!. You would still end up with a satisfying build by gearing down 200W servos,
you might start to notice the reduction in rapid traverse but you wouldn't see much difference otherwise.
Craig