3D guitar neck frustration

First off I am completely new to the CNC world. Not unfamiliar but unskilled. I have done some 3d drawings in solidwork, saved them as STL files and purchased Meshcam to do the toolpath and generate the gcode, I am using Universal gCode Sender into the X-carve. I have tried using "grblControl and a couple of other gCode sender programs with consistant results “SAWDUST” and a very odd cut pattern. I downloaded a trial version of CutViewer to simulate the cut from the generated gCode and it looks like it is doing the right job. see pics below. in each case it appears that ,for the lack of a better term, the X-carve forgets where it is. When I watch the gCode sender viewer/simulation the X-carve is not anywhere near the point shown on the viewer. I am totally lost in this process. after all the frustration I simply make a couple of signs to be sure I am not crazy.

Of course I am not standing over the machine at all times but I am nearby is it possible that the machine is jumping teeth as it tries to cut along the Y axis? just swinging in the dark here



Yeah, you’ve got some machine calibration/setup issues.

Things to check:

  • Belt Tension
    Check to make sure that the belts are tight enough that they won’t slip or jump teeth on the pulleys. Also make sure that the belt ends are secured to the clips using something more than just the screw tension.

  • Pulley Grub Screws
    are they loose? Make sure they’re tight against the stepper motor shaft. Use thread lock if you need to.

  • V Wheels and Eccentric Nuts
    You shouldn’t be able to easily spin any of the v-wheels with your fingers. Adjust the tension on the eccentric nuts to make sure that the v wheels have enough tension against the makerslide. You should be able to spin them with moderate effort.

  • Wiring
    Be sure you have good solid connections at all the terminal blocks and on the g-shield. I recommend using crimp-on spade or fork connectors rather than just bare wire.

  • Stepper voltages
    If you notice your stepper motors “chugging” and you know your wiring is good, give the little potentiometers in the g-shield a little goose.

Start smaller. Get good with the machine using small projects with softer cheaper woods and materials. This will give you a great reference for what can go wrong with the machine in a much lower-risk environment.


Do some test cuts.
Circles with squares in them are good.
That will help show what is going on.

A lot of times when something is slipping it will show up as each layer of a cut being off.

Are you set up to use easel?
Try the same test cuts with that as well and that will help to see if there is a software issues with you meshcam settings.

From the photos it looks like slipping / missing steps in the Y axis. But if it is really going of the rails and cutting crazy shapes it could be a post processor issue.

Making sure your post processor header includes the gcode to set the units to match yours ( “G20” inches or “G21” mm) and use absolute addressing (“G90”) as opposed to incremental addressing (“G91”) is a good idea.

I am not an expert and can only offer you a little bit of what I have learnt. I have put it in one of my many X-Carve videos. I hope that it helps.



The sign making has gone well overall, but the 3d stuff has not. I have been trialing a good deal of cam then gcode/grbl stuff. but I have been anxious to get to the necks. only using Hoe Depot 2x4 for now no good wood. but good advise more smaller projects will be in the immediate future :slight_smile: thanks

I have been doing some test cuts. but I do notice the the eccentric nuts get loose often, quite annoying, I have been using Easel for all the 2d cuts the only thing that did not work well in Easel is the dust shoe project. regarding crazy shapes none of that really, it just appears like the proper cuts keep moving forward on the Y access just a couple of deep drilling holes “panic button” issues on occasion I have been using the G20 command I read that somewhere also using G92 X0, G92 Y0, G92 Z0 when I line the spindle up with my stock 0/edge, recommended on one of the forums. as you pointed out it does look like slipping I am going to take a hard look at resetting up the machine again. I know those eccentrics have vibrated loose a couple of times already.


brilliant video, great help thanks.

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I put lock tight blue (which comes in a red tube for some reason) on them and and the set screw on the motor pulleys. That seemed to help a lot with keeping them from vibrating loose.

I have not used G92.
When I use UGS I do a home cycle. That resets the machine zero to the home position
Then jog the bit to the edge of my material (UGS does with with incremental commands that is why I like to be sure to reset it to absolute mode when running my code) and use the reset zero button.

Ahhh I hadn’t considered the set screws on pullys thanks for the tip