I own a MK2.5 from Sienci Labs, and after 2-3 years of use (time flies!), I’m working on a project that covers the full table area. During this project, I discovered that my wasteboard isn’t perfectly flat—the bit was cutting deeper into two diagonal corners. I resurfaced the wasteboard, assuming I’d made an error during the initial surfacing, but the same issue persisted.
Using a precision straight edge from Veritas, I confirmed the problem: measuring diagonally from one corner to the opposite shows a 1mm gap under the straight edge, while checking the other diagonal reveals a 1mm hump in the center. This suggests the table is twisted.
My conclusion is that the black steel feet supporting the bottom rails are uneven, causing the front and back rails to sit at different heights and creating this diagonal twist. Can anyone confirm whether this diagnosis makes sense? If not, I’d appreciate any explanation for how this situation could occur.
If this turns out to be a manufacturing defect, I would appreciate receiving a replacement set of feet that are all the same height.
Side note: I did verify the bench was level before starting this project, but I’ll double-check it tomorrow and confirm my findings. I recall moving everything by a foot after levelling, but don’t expect it made a difference.
Before suspecting the CNC machine, I’d double check that the table it sits on is itself flat and warp-free. Any distortion in the underlying table will telegraph through to the machine.
Your hunch sounds correct - if all four legs are not level, you can get a cup in one diagonal and a hump in the other. This can happen due to building movement (we live in California where we deal with both seasonal and earthquake movement!) , floor irregularities, etc… One fix is to shim up the two “low” legs and let the table readjust over a day or so.
A laser level and a 123 block you can move around the table top is an easy way to check without dismantling everything to fit a steel rule
My top wasn’t perfectly level. I fixed it and will try again to flatten the wasteboard this evening. I think my issue might be related to the leg adjustments. I use adjustable, screw-in feet like these:
@dfrechette I don’t believe that there is anything inherently bad about those feet. However, as I asked before, are your legs one length of 2x4 supported only where they meet the top? That’s what the pic seems to show. If so, the entire table can and will rack. Plus, you said that you moved it. Are the legs plump to the floor and the table top?
I seriously doubt that your problem will be traced to the feet attaching the rails to the top.
