Oh well.....still quite chuffed that I managed to weld them pretty damn level Will carry on grinding and welding and getting ready for pouring the epoxy (best buy some I guess!!) OK another question :) Is it better to drill and tap the holes before epoxying or after? I was thinking before as we have a mag drill at work and that would make drilling the holes much easier first, but then would need to fit the bolts and make sure epoxy doesn't stick to them and then there's the question of the miniscus round the bolt?

Now playing devils advocate here....how much accuracy do I need? There's a CNC router I know of that looks a bit like this.....
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which has supported round rails bolted straight to what looks like steel rectangular section and that machine seems to put out some nice accurate shiny aluminium bits I'm mostly going to be cutting balsa, ply, carbon fibre, wood engraving and the odd piece out of aluminium (probably upgrades for the machine itself if most build threads are to be believed...!) so just wondering to what degree I go to with the levelling? I've got nothing to measure the accuracy of the epoxy once it's set and have no way of accurately telling if the rails are flat. I don't want to go out and spend a small fortune on a surface plate or engineers bevelled edge 1300mm long sop suggestions on a postcard please?