X axis skipping?

Hi there peeps!

I recently built a LR2 and was very excited to start using it. Up until now I’ve only done some simple tests in mdf and a few 2d cuts in plywood. All of that went pretty smooth. I learned a not already doing that.

The newest project I’m trying to make is some type of cookie cutter plank. Here in Belgium we have ‘Sinterklaas’ instead of Santa and the speculoos cookies are traditionally made with wooden stencils.
We designed a ‘sexy sinterklaas’ and started cutting in some padouk that I hadn’t used before. Cuts looked good, but at some point a shift was happening in X. I’m not sure when exactly.
Since then I’ve tried 3 different ways of doing it:
First attempt: 1/8" flat endmill, 6mm doc and 8mm/s feedrate
Second attempt: 1/8" flat endmill, 3mm doc and 8mm/s feedrate
Third attempt: 1/8" flat endmill, 3mm doc and 5mm/s feedrate.

I’m using fusion 360. Tested the file first in some mdf to be sure that fusion worked the way I expected it to and everything looked fine, so I’m pretty sure it’s not an issue with the gcode.
It’s only skipping steps in the x direction, which is the short side of my design in the pictures.
I also think the shift happened twice on the last attempt.
The stepper is getting hot, but not so hot that I think it would be a problem.

This is a big issue for toolchanges, too, because the origin moves. (I’ve broken two 1mm bits already :’( )

If you need any more info to help me debug the issue, I’d be glad to provide the gcode, fusion file… Anything. I just want my machine to work as expected.

Version 1:

Version 2:

Version 3:

Thanks already for any insights and help!

I am still in my learning curve, so I could be totally wrong,
but Padouk is what we call “hardhout”. So if all goes well with MDF, I believe you might need to slow down your cut, and do multiple passes (depth) to the final DOC, when using Padouk?

btw, what happens if you turn your wood like 90 degrees? The wood grain goes in the same direction on all examples. So just wondering, if you would turn the wood, if in that case it would be the Y axis that´s having issues?

I would add to @Olivier 's comment:
A loose grub screw can cause this problem. The little screws holding the gear to the stepper motor can slip if not tightened enough. This is a really, really common problem early on:

It gets us all: New printer time? - #586 by vicious1

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Slowing down and going less deep is what I thought too, so I tried that. Should I go even slower? The first attempt took about 45min but the last one was more than 3h… I can only go so slow before it no longer seems worth the trouble.
Are my expectations for the machine too high?

Is padouk much harder than birch? I was originally planning on using birch but the stock I have is a bit too thick and I didn’t want to waste it. Do you know if that would work better?

I’ll try the next one with the grain in the other direction, I’m curious to see if that changes the problem to the Y axis.

Thanks for the links. I already heard about that, but didn’t realise it was such a big, common issue. I’m going to tighten them for sure!

I feel you. Was making a 5mm deep carve for just 3 words last week, it took 1,5 hours. That was not what I expected. obviously I will need to learn to work with the machine too. Maybe go faster but not that deep per pass, and add one slower finishing pass. But I don’t know what I should expect in terms or speed.

Yes, it was something I immediately noticed in your pictures. However, keep in mind that only the X has 1 stepper, so the Y should be stronger because it has two of them pushing/pulling.

According to this Dutch article, they are pretty similar in hardness;

Birch is 3.4 to 5 on the Eiken Index. Padouk is 8.6. Padouk is waaaay harder.

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I found something similar to this. Weird that the information is so wrong then? Do you have a good place to look for stuff like this @barry99705 ?

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ok, it seems that the article is wrong then:)
Anyways, according to this page Relative Wood Hardness Table (precisebits.com)

  • Birch 3-6 kN
  • Pterocarpus / Padauk 8.8 kN

So that´s in line with @barry99705 ´s feedback.


I have noticed my X axis slides, but it is the roller wheels that is sliding sideways, propably because the aluminum they run on is slippery…An issue i need to look into since it is 2-3mm…

I didn’t see birch in the article you linked to.

So I might have made a translation mistake… I meant beech, not birch. Woopsie! :man_shrugging:

I’m trying something new on there right now in the big piece of beech I have. Didn’t get the grub screws any tighter though, so let’s hope this all goes smoothly. Fingers crossed.

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