Reflecting on the dynamic load applied to the ballscrew by the Impact tool.
For many reasons I would prefer to use timing belts instead of ball screws. They do not suffer brinell pitting damage
This search came up with some useful links.
https://www.google.com.au/#q=brinell+pitting

I built this router with timing belts (The Z axis only in this machine is a ball screw but that could be changed)

I know the budget is finite but would it be possible to make a belt driven machine Or two machines One for impact work and one for Routing? Maybe sharing the electronics?

This Is the Router I built with a mate using timing belts for a non profit Men's Shed. http://www.machsupport.com/forum/ind...?topic=23730.0 There is a small video. It works really well and is used by the group so much there is a waiting list.

Regards
John