How to test that my X-Carve is cutting at the same level?


first off great machine after setting up for 5 days!

I noticed a small problem today doing a larger cut.

I made a large rectangle cut out of 70x70cm 5mm acrylic.

The machine was tested before on cutting some letters into wood and looked great.

However this time it had to cut up the x axis for 56cm and 36cm across the y axis.

as it went up the x axis the bit started to cut shallower and shallower until it was no longer cutting the acrylic until a few passes later.

I am not sure what could cause this. The spinlde mount is level and I am not sure how to check the waste board is level with the spindle head through all corner of the waste board and middle.

I have to some engraving of paint off acrylic which needs to cut at a depth of 0.15mm, so I need to tune it to the best I can to make it look great.

any help is much appreciated, will also try and upload a video example.


I used an angle square to test the top of my X axis at various points across the wasteboard.

Other than that, I would go to a high point (for me, it was at X0, Y0) and lower my bit to just touching material, and then move the spindle around the board to see where low spots were. You’ll notice a distinct gap if your bit was touching the wasteboard at one of the edges, and then is hovering above it in the middle if you have a low spot.

Hi Philip,

I have similar issues as I’m cutting/engraving thin (0.3 - 0.7mm) copper sheet. My 500mm X-Carve varies in “height” from corner to corner as far as the spindle is concerned.

You can spend ages measuring it, shimming the waste board, measuring and adjusting the GCode etc. I’m lucky to have an ancient measuring gauge that I mounted in the spindle for just this task. (pics below) My high point was also at X0, Y0 with my worst at X300, Y300 (26 thou) with X150, Y150 (23 thou) being a close second

But easier still is to bolt on another 3/4" sheet of MDF and then running a clearing pass that machines the whole secondary board at the same height (as far as the hardware is concerned) which should present a level surface for subsequent jobs placed on top of this.



Yep, even if you surface your entire waste board, changes in temp and humidity can eventually warp it. If you need something to be totally flat, throw down some scrap, make a pocket large enough to hold your workpiece, and then you’re good to go.

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thanks Ian,

its a good idea with the 3/4 mdf and running a clear pass. Pressure gauge is also a great idea. Would you run the pressure gauge through the board and read its results as you move across? I am sure I can get my hands on one.

I am still not sure what the cause is. Whether its the wasteboard or its perhaps the spindle or even the aluminium rails.


thanks for the idea will give a good indication quickly whats going on without needing to run a carve. Its given me an idea to attach a marker and see how consistent it is running it throughout the board.

If I do find irregularities, my board is the 1000 x 1000mm wasteboard from inventables, I still need to detect where the issue is coming from. As I am not sure if it could be just the wasteboard.


Hi Peter, I believe you make a very valid point. Based in Singapore we have very high humidity.

most of the parts and spindle are starting to show “surface” rust appearances now and I can imagine the mdf board has slight warping.

I am wondering if its worth buying or cutting a aluminium board.

A loose bit can creep (get pushed) up in the collet. Be sure you are tightening your bits. Most common mistake I see my students make.

The gauge Philip has a small ball bearing in the tip pressing into the top surface of the board. As I push the carriage around the board it shows the height relative to the reading shown when first set up. I can get about 10 thousands of inch travel at X150, Y150 by just pressing down on the waste board. But the 500mm X-Carve has no central support underneath unlike the 1000mm machine.

MDF is well known for swelling in humidity so sealing it including the edges is good practice to stop the humidity getting in. Also worth trying to laminate a few sheets together which makes it much more rigid.

But as Peter says, doesn’t really matter what you do, it’ll eventually warp or you’ll destroy the surface with a bad path anyway. Much better to have a sacrificial waste board that you can happily destroy and clear pass or pocket and replace as and when problems arise.

The extrusions underneath are 20mm, but don’t think I can source 20mm MDF, but can source 12mm and 9mm MDF sheet. So my plan is to add a sheet of each (21mm) on the underside of the waste board making the top surface much more rigid. Whole thing will also be screwed down to my table from underneath as well making it super rigid. I can then add a sacrificial sheet on top which will be clear passed and replaced often. In theory that should allow accurate cutting/engraving of very thin sheet material and also without any flex in the waste board. Two birds, one stone. :smile:



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I have attached a photo as you can see the spindle where the cut starts and stops on the first pass.

the cut depth pass was 0.3mm.

I will take all the advise here and post some results tomorrow.


I like how everyone immediately jumped on the swell/warp bandwagon. Come on folks! This is extremely common and is based on the installation. The mdf boards are not coming warped and the height dimensions are noticed right away. There are other posts on this subject. I wish there was a way to accurately install the components so everything is “true” but I haven’t figure it out and I have literally taken my x-carve apart many times now trying to square it up. I believe so far the best suggestion has been to pocket out a scrap piece of wood to get level cuts. Thats just a bandaid though. If someone had a better method or could figure out the un-level issue I would be game to help try out any ideas.


Don’t know if the bandwagon has been jumped on James. :smile:

I’ve also spent time taking it apart, shimming, remeasuring etc. to no avail. I think that replacing the fixings for the Y plates with an eccentric would allow very fine movement of all four corners to level the Y above the waste board. I think that would be a good start to ensure all four corners of the working area are at the same height. Would still sag in the middle (on the 500mm) but that could solved by reinforcing.

I’m sure the whole thing can be truly squared up on a perfectly flat and level table. But it’s the level of accuracy required that dictates what needs doing.



I think the definition of flat is relative to the x axis gantry. If the waste board is the same distance from all points in relation to the tip of the spindle, it’s flat.

If the table supporting the machine is racked,or twisted, you will have nothing but headaches.

For squaring, measure the y rails from right rear to left front and vice versa. If the measurements are equal it’s square.

I also ran my y axis front to back several times, stopping it up front. I then measured with a caliper from the outside front edge of the y axis rail plates to the leading edge of the y axis motor plates. Again, if the measurement is the same…

thanks for the tip on squaring, I am not sure what the best way to go about this. I am fairly new to CNC and not sure what equipment to use to get better accuracy.

I have attached some photos today of test I ran. I also did a run with a pen on flat, clamped down 5mm acrylic covering the whole waste boards area 70 x 70 cm. It showed quite a few areas with no pen marks. Its roughly around 0.05mm out of alignment on the z axis, but it could be a y axis issue? Its far more noticable in the middle of the board as there is no pen marks at all. I start at the 0x 0y position with the pen just touching the board.

I did a few simple text and shape tests at 0.15mm cut depth passes cutting out 0.2mm. Ring marks are very prominent in the star example and the black/white acrylic sheet some areas did not cut the surface out. A alot of ring marks can be seen on the black/acrylic. everything was clamped down and used default settings from easel on the 300w spindle.

What mill are you using? If I remember correctly, only the 1/16 and 1/32 in the basic kit (if that’s what you ordered) are flat, the others all have pointed tips which will give grooves.

I had the same issue with running ghost passes near the middle…my wasteboard just couldn’t get flat enough no matter how much shimming and adjusting I tried…

So I went to Lowe’s and got a 1/4" shank (you have to have the 1/4" collet) - 3/4" straight flute bit and went to town.

Hi Alan,

I am in the same boat and will make another layer with mdf as a wasteboard that fits the x-carve.

I believe the issue is my y axis by I am not sure what sounds or tightness should be correct. it does seem that there is more vibrations when the machine is moving on the y axis.

After weeks of efforts I continued to have a difference of 0.03 inches on several spots on my 1000mm xcarve. By raising and lowering the z axis at 0.001 inch increments i first created a map of all the low spots. Then I laced those low spots with Bondo (Body Filler With Hardener) and just eye-balling leveled it to the best of my ability at least 0.06 (1/16) inches higher than the rest of the surrounding and let it dry overnight. Next day I took a quarter inch flat end mill bit and milled all of the putty filled area while stepping down 0.001 increment at 20 inches per minute feed rate. After 9 hours I had a perfectly flat surface which is true to the mill every mm of the cutting area. I can now cut inlay patterns for up to 1/64 inch accuracy.

Hope this helps.

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