Self Leveling Concrete

Not sure if this is crazy talk or not but has anyone ever thought of using self leveling concrete to create a level base for their XC?

Just curious.

The CNC itself dont care wether the base is level or not, you could hang it upside down if so inclined :slight_smile:
What is important is that the spoil board surface is perfectly parallell to elevation (Z axis)
By skim cutting the spoil board this is ensured.

2 Likes

It’s not a bad idea. Concrete absorbs vibrations well and is very sturdy. I personally prefer to have my machine fastened to the table for many reasons, and that would certainly be more difficult with concrete, but doable.

Probably could embed some studs in the concrete, then fasten it to the XC with some L brackets. I’m going to try this soon.

“What is important is that the spoil board surface is perfectly parallell to elevation (Z axis)
By skim cutting the spoil board this is ensured.”

Not exactly. Skimming the wasteboard corrects Z clearance deviation and gives you parallelism to the specific point below the cutter at any given point, but doesn’t ensure overall parallelism. And doesn’t at all ensure overall perpendicularity. If the base is not planar and, say, the back left corner of the machine is lower because of a dip in your substrate, you will get tramming deviation. Basically the machine will rack a bit. The symptoms would be imperfectly square sides on a contour cut, and sawtooth lips on facing operations. (But would have to be a significant skew to really matter).

Stick a nickel or two under one corner of your XC and you’ll get the picture.

After skimming a wasteboard on a machine without a perfectly planar base, it would be like flying a plane at constant relative altitude over contoured geography. You could be hugging the the ground at constant relative altitude, but a varying absolute altitude to sea level.

In the case of your X carve, you want everything Z-related to be referent to an absolute substrate before skimming the wasteboard. At least as much as it matters.

So self-leveling concrete would give you a pretty flat surface (important) that just happens to also be level (not important.) It’s the cheaper alternative to getting a hefty piece of granite or quartz countertop.

The machine isn’t powerful enough and belts insufficient, but I would be super happy if I could mount the XC on a wall. If I ever rebuild with ballscrews and linear slides, I’d think seriously about designing for that.

“Probably could embed some studs in the concrete, then fasten it to the XC with some L brackets. I’m going to try this soon.”

Studs are not at all flat. would be better just coupling directly to the concrete and substrate with some anchors.

Probably used the wrong wording. I didn’t mean framing stud. I meant like a threaded stud or screw. Btw, very nice explanation on paralleling. Thanks.

Oh, got it. Yeah, that makes sense. My mistake.