OpenPull From CNC Kitchen.. attempt

This build will evolve as I go..

Having a go at building a pull tester like the one on CNC Kitchen "OpenPull" project.
Watch Stefan

GitHub - CNCKitchen/Open-Pull: DIY Universal Test Machine

I'm a practical arduino noob so this is a struggle.

electronics so far;
Arduino nano
dq542ma servo drive, can use two if one not enough
24v PSU
bluetooth hm10
microSD card adapter, for arduino
hx711 board
300kg load cell

Trying to go as cheap as possible, I was lucky to score some bits and parts of 45mm extrusions from work. For the pull drive I have a bunch of used direct drive steppers with 1/4" x 16 acme screw nuts. McMaster Carr had the acme screws in 36" lengths for cheap. The steppers proved to be way too weak for this purpose so I use the rotor and bearing from the steppers and fitted a large 88tooth 3D printed spur gear to it and an 11 tooth to some 269ozinch steppers I had. Could not get the rotor off the brass shaft so adapted the gear with the rotor on it (I tried heat and a press! IDK how they have that rotor secured to the shaft!).
I'm surprised there don't seem to be many people building their own of these and the instructions are very limited.

Cheers
Gary