Router Build Mk 1

[Neale]

I could I suppose easily convert to direct drive later if backlash becomes an issue.

There are plenty of us using belt drive without backlash issues. Properly set up amd with the proper belt/pulley combination, backlash isn't a problem with belts. I use two drive motors for the master and slave X axis ballscrews on my router with short belts but there are quite a few builders who have gone for one motor with a long belt which works fine. I think that you should make the direct/belt drive choice based on other factors. I went belt drive as it meant that my motors are tucked in inside the overall build envelope, I can change drive ratios if I need to, and I get a bit of isolation of motor stepping from the ballscrew. It's also easier to build and adjust mechanically. Direct drive means very careful alignment (even if you are using Oldham/Lovejoy/flexible couplings). Both are viable methods but be aware of all the trade-offs before deciding.