The Best Steppers/Servos Setup Thread

[m_c]

but the machine doesn't need the worlds biggest servos, its not like it will take massive heavy billets. are there no small decent servos?

the table doesn't need to move at 1000mph.

There are, but gearing is the problem.
Stock steppers are 1.1Nm stall, with a gearing ratio of 12:30, giving roughly 2.75Nm at the screw.

A 50W 3000rpm servo, which from Kinco is 83mm long (should fit in a similar place to the steppers), gives 0.16Nm. So to get similar torque you need in the region of 17:1 gearing, and you limit screw speed to 176RPM (roughly 880mm/min).
Move to a 100W version, which from Kinco is 110mm long (I think this was very borderline for fitting to the X, and wouldn't fit on the Y), gives 0.32Nm. Ratio needed is about 8.5:1, and you'd get 1.6m/min speed. If you could manage the gearing ratio, this size would probably be a good match specification wise, but 8.5:1 involves a very big pulley. A gearbox would be a good option, but you add cost, and length.
A 200W 3000RPM servo, again from Kinco is about 120mm long, and gives 0.7Nm continuous torque. You need a ratio of about 4:1, which is very achievable., and you'd be up over 3m/min if you ran it at full speed.

Off course all those figures are based around the continuous/rated torque of the motor. Instantaneous/peak torque is typically 2-3x the continuous figure, but you normally rely on that for acceleration, which is where you should get the real benefit over steppers. If you were to run the figures above using the peak torque, then you would have to limit acceleration, and performance gains would be far more limited.

IIRC, the servo Triacs used about 200W DC servos. I'm sure I read the Y servo stuck out the back of the machine, but I've got no idea how the X was fitted.