DIY surface grinder

[tonyfoale]

Wow, that 20mm lead really raises a question. 20mm seems unusually large, and considering the mass of your system (granite plate & mag chuck), it certainly increases the size of the motor! Care to share some of your thoughts about some trade-offs now?
*Wide-full-open

The screw with 20 mm lead works fine under my tests so far but it is not necessarily the final choice to drive the table. Back in 2009 when I was at Segway developing a project for GM we used a motor, pulley and wire to slide the top part over the bottom part. That is an option that I am thinking of using, it would be more tolerant of wayward grinding debris over time.

https://en.wikipedia.org/wiki/General_Motors_EN-V

and video