Quote Originally Posted by JAZZCNC View Post
If you are going to do vibration tests then I wouldn't waste time testing individual pieces of profile or steel etc off the machine because all that matters is the tool. Testing at the tool is the only thing that matters IMO. You'd be better investing time on designing a strong Z axis.
Yea, that's a good point. I did a bit more reading around the subject and a guy on CNC zone recommended pea gravel in the non moving parts and nothing in the gantry, for now. I'll try that first and see where it is. I actually have a MIG that I bought years ago but never got around to learning to use the thing, a gas-less 150 from draper (I'm not sure if they're much good). It's been shelved in my dads place for years but maybe it's time to dust it off.

I think the Z axis I have is pretty solid though, it's foundation is milled from stainless. I know the opposite arrangement than most recommend, with the rails on the z plate which seems to be preferred, but it was a simple solution for me. I've tried to keep everything as close to moving bearings and having as little overhang as possible. The Z only has 100mm of travel but after using my other machine for a few years I realised I've never needed to mill anything over a couple of inches thick so the z overhang was really compromising the strength. That plus the momus design is not very good generally. Live and learn. I thought it would be a good idea this time for me to keep the gantry and Z axis as tight to the part as is feasible.

It's a shame about the profile, maybe I'll change it for something heavier but at this stage I might just run with it and see how it does, should be easy enough to swap it out for a heavier profile down the line.