I'm retrofiting a Mill.
I have changed the original screws [22mm or 7/8], and put a ballscrew of 25mm.
About the Stepmotor, I take a Easy Servo: 86J18156EC-1000 + 2HSS86H
It's a Nema 34 of 8N.m using a closed loop system. [Some people says it's a 12N.m]
My ballscrew is a 5mm per revolution.
I have connected the motor to the ballscrew using a 3:1 pulley as the picures bellow.
I have no idea how much torque I need to move my axis X and Y... so I did it using a 3:1 ratio. Have no idea how much RPM the stepmotor gets.
To do the Z axis I will use a 2 systems os 3:1 ratio doing a 9:1 ratio. My friend told me to drill, it needs too much torque, so I should use a great pulley ratio.
PS: at Z axis I will use a heavy weight behind the Z column to take off Z axis weight.
My doubt is: 3:1 ratio for X and Y sounds good? How much RPM this stepmotor gets travelling my table? Anyone uses this stepmotor?