Quote Originally Posted by JAZZCNC View Post
Wait there's a big difference between a router and a milling machine so it's not that simple.!

The milling machine is often rotating the ball-screw much slower with a lower pitch ball-screw. A router is using a high pitch and spinning the screw upto twice the speed and often much longer length (heavier) screws so the inertia becomes more of an issue. Also, servo's or steppers change the outcome. I've got a feeling muzzer is using servo's which have much higher torque than steppers.!

The weight of the pulley and the effect of inertia DOES affect the machine negatively in some circumstances ie: 3D where you are accelerating and de-accelerating quickly with lots of direction changes. Rapid positioning like when drilling lots of holes over a large area where you need to accelerate hard and then slow down between holes.!

All these kinds of operations are affected by the diameter and length of the screw which play a big part in the effect inertia has on the system, so any extra weight you add will only affect this negatively. If you plan to operate at high feed rates or do lots of 2.5/3D work then think carefully about any extra weight you add.

If the screws are long and the gantry heavy then 4.5Nm isn't a massive amount of torque if rotating the screws at higher RPM's.!
Thank you, definitely appreciate all the information.
This is for a diy router milling machine. I'm still in the initial design phase, so I have not ordered any parts yet.
Right now I'm planning for Nema 34 size motors, but that 4.5Nm figure (or motor type) is not final.
I'll figure this out once the dimensions of the machine are locked in.

I got curious and checked the mass of a 36T htd 5m taper lock pulley, and they are listed at 450g.
Definitely more than I was expecting.

I'll be sure to post my design and ask for critique and comments before ordering any parts.