Stepper motor - how to calculte what I need


I have a project to build a standing desk that will be level by 4 stepper motors and control by 1 Arduino.
Motors will be put on the 4 corners of the desk with leadscrew. The desk will move verticaly along screws.
The total weight of the desk + the hardware on it, will weight around 50Kg.
I do need the motor to be fast, but they need to be precise, and they need to be able to move and hold the desk in place correctly.

Based on that, could you tell me which motors I need to buy and more important how have you calculated the needed torque.

Thanks a lot

Fo you think that this will do the job?

I think you will need to set up an experiment with a screw and a load an measure (even roughly) the torque required to turn the screw. Unless you use expensive ball-screws there will be a lot of friction as well as the weight to be lifted. I can't imagine that ball-screws would be justified.

Another complication may be the way the weight is distributed on the desk. Even with 4 screws I would be inclined to design it so that each screw is capable of moving 50% of the total weight.

There is a simple idea for measuring torque in Stepper Motor Basics


Are your leadscrews in tension or compression? How long? What diameter? What pitch?

(Basically you need to provide all the information).