Hi All

I am new here and not sure if this is the right thread, I need some expert people advice if you can please help me in that thank you.

I am have a problem with choosing the stepper motors and Ball screw for converting my milling Sieg SX2P machine to CNC.
After searching online for days I come across two motors which seems reasonable and powerful that is Nema 425oz and Nema 570oz now I am confused which one should I go for or is this bad choice or should I choose some other motor ?
please see the link below for both. Can yo please advice me on that

https://www.ebay.co.uk/itm/US-DE-Shi...1&isGTR=1#shId

https://www.ebay.co.uk/itm/3PCS-NEMA...1&isGTR=1#shId


Other confusion I have is choosing a lead screw which size I should choose 12mm, 14mm or 16mm diameter.
I have found one which seems like 12mm with reasonable price please see link below, can you please advice me about ballnut screws.

https://www.aliexpress.com/item/32863518333.html



Thank You All