(I'm going to give everyone a thanks later on)

It is my second go at it :)

There is practically no turning play in the beam, and there's only 4 of the 16 bolts screwed into the carriages. The distance between each of the carriages is as high as I could get away with (to assist in reducing turning play). I have a slight thought that there could be some skewing in the steel, but I hope I've used thick enough steel (which was the problem I had in the first version).

The level of accuracy I need for a car body is not much - 3mm is probably good enough (most kit cars are built from by hand, and they're accurate to around 10mm). My worst case aiming point is 1mm, but theoretically I should be getting 0.0625mm (half-stepping) - the controllers will do 10,000 steps per revolution, so 0.0025mm is the best with the ballscrews I've got.

My priority at the moment is speed though - the car will be made out of blocks of foam, and if a whole block needs cutting, then I've estimated 1 hour per block for milling. There's about 64 blocks to cut, which means 8 days (although some "blocks" are just thin strips which won't take much time). The original machine we were looking at over 1 day per block.

Mondeo - I found the other driveshaft this evening when I got back, so it should be fixed tomorrow (probably 3ish hours - that's how long it took me the last time, although most of my tools aren't in my possession [either in the workshop, or at a mate's house]).

Family - I'm not married, and I don't have any kids, so that doesn't really take up too much time