Step 12: Mill bits of mill
After a bit of faffing around, it became obvious that the best way to remove backlash was by making new ends of the ways to add ball bearings.
Work in progress
Step 1: Model it
Because I don't (yet) have a CAD setup, I'm basically coding stuff up in NativeCAM which is tacked onto LinuxCNC. This is OK for simple stuff but gets incredibly tedious very quickly, especially standing at a machine in the corner of the shed. It's also a pain that you have to constantly account for things like the width of the cutter in every measurement you make.