Stell frame cnc 1500X1000. Adjustable table your opinion please

[Boyan Silyavski]

I've been working on my machine this evening, and I think that we are a very similar stage of build! I was levelling the frame of my machine (similar size - cutting area about 1500x750) and thinking about epoxy. I have already bought my epoxy (Reactive Resins low-viscosity with slow hardener) but they say that it should not be used below 8C. In my part of the UK at the moment, that's about the night-time temperature and daytime is only about 12C (and probably slightly cooler in my garage).

I have done the first machine at 14-16C, but i believe any lower is not good idea.

What I don't know is what kind of tolerance you need to work to with Hiwin rails - what kind of relative twist in the two rails is OK? If both rails are perfectly horizontal in both planes but one is, say, 1mm higher than the other, would this matter? On my machine, that is a twist in the bearing block of about 0.06deg, or 0.001mm across the rail. Doesn't sound like a lot to me, but I have no practical experience of the real-world tolerances on these things.

For 20 size z1 preload :
-mounting surface parallelism 0.02mm
-block mounting surface 0.01mm

It will withstand more, just loosing life expectancy.

I'm planning to epoxy first and drill/tap through the epoxy and rail later. My feeling is that this will be easier, and certainly better than trying to remove the epoxy that has leaked into the tapped holes.