SERIOUSLY weird 'slipping' issue - need help fast

Hey, Matt here (DIY Perks on YouTube). Got a project coming out that uses the x-carve extensively, and I’m having some seriously weird issues with the x-carve that I’ve not been able to work out.

It’s easier to explain by showing, so I recorded a quick video of the problem:

The idea was to have the project available as a kit, but due to the x-carve acting up I’m this close to giving up, so any help would be very much appreciated.

Not had any problems like this until now - all of the pulleys are secure with threadlock (confirmed to not be slipping), and when the issue happens there is no usual ‘judder’ that happens when the stepper motors are put under too much pressure. A different laptop was tried as well with the same results, and I’ve grounded the sheathing on the stepper cables. Also updated the drivers and tried different tensions on the pulley straps. It happens randomly on different parts of the cut, and usually between z axis changes (looks like stair stepping from the side of the ones I did with more passes). Seems to happen on both the x and y axis.

The problem isn’t loosing steps - it’s gaining them. That’s what’s so weird about it! The steppers function smoothly through all of this - no lost steps from the steppers themselves.

I didn’t initially no, as it didn’t seem to need it (done hundreds to cuts and it’s been fine). I will try it and see if it helps matters.

As far as I see on your video, you have 24V spindle. That depth is too much for the type of spindle you’re operating.
Also check to see your bit’s health, seems like a little dull.
Check your depth, spindle speed and feed rate. Your machine is suffering from deflection.

I wondered if it were the bit being dull, so the cut in the video was done with a brand new one. Tried with much lower depth passes too with the same problem.

I’m currently calibrating the voltage going to the steppers and see if that helps. Still not sure how it went further than it should if it’s loosing steps, but Phil seems to know what he’s talking about so I’ll give it a go!

Deflection takes that into complete different path. This one was lucky, I’ve seen bit was traveling all over the place until operator realizes the problem.:confounded:

Also I want to add that, we do have friend in New Zeland operating X-carve with that spindle since beginning with no problem. All you have to do is go easy. Roughly I can say is; If you’re cutting plywood, your spindle speed might be around 15000, feedrate is 35~40 ipm, depth per pass is 1/3 of the bit size.

I’m pretty new to the CNC world, but wanted to add my observations and hopefully they’ll help.

Check your power supply voltages, they could be off enough to affect stepper behavior.
It does appear your first cut is too aggressive and deep.
Your vwheels should have more resistance than what you showed when you spun the wheel with just one finger. Mine don’t move at all unless I use both hands.

Hi Matt,
Your video on the headphone stand is what made me buy an X carve.

I’ve had issues with the cut jumping around when working on large sheets, putting a screw in to the waste bored near the part you cutting out helps. Its worse with the thinner material.

From the first part you cut which came out perfect, are you cutting from the same file with the part in the same location on the board? I’ve had issues with easel when copying parts, slight variations seem to crop up, meaning the same part can be slightly larger or small then the others.

Hope you get to the bottom of it.


I think I owe Phil a beer. After calibrating the potentiometers it seems to be much better. I’ve only done one cut so far, but there were no issues with it.

Will be doing more cuts tomorrow so hopefully it will prove to be reliable. Pretty hopeful about it!