[Resolved] X-Axis keeps changing angle

I have the 1000mm x-carve. My x-axis keeps changing the angle that it travels on. I recently faced my spoil board and engraved new grid lines on it. Things went well for a few programs.

Then I noticed that my x-axis was no longer following my grid lines anymore. I set it right on the grid line on the left side, and by the time it reached the right end of the machine it was below the line by about 1.5mm.

I ran a few more programs, and now the distance it is off is probably 3mm. The angle changed again. Very frustrating.

My thought is that I have a y-axis belt slipping. Does this make any sense? Has anyone else had a problem like this? I would like to know that I am possibly on the right track before I start tearing things apart again.

I would really like to stop working ‘on’ my machine and start working ‘with’ my machine.

It sounds like the left and right side of the X axis are not at the same distance from the front of the machine. There is nothing stopping the X axis from racking, you can actually hold the left side and then push the right side forward or backward a few belt notches. So you need to the left and right side back in alignment.

The way I do it is with two 123 blocks, I position the blocks against the front brackets and then pull the X forward until both sides are firm against the blocks. I may need to pull one side or the other a few notches forward or back to get them aligned, then I push the X to the back of the machine a alight against the rear brackets.

If you do not have 123 blocks they are a great investment

I just checked the squareness of my machine by measuring the diagonals. Looks like it’s out by about 1.5mm. I’ll get it squared up and see how it performs. Thanks for the idea, Bob!

Thanks, Allen. I may invest in some soon. I am going to try and re-square and see how it goes first.

Thanks, Robert. I already checked the pulleys/set screws as well as the V wheels. That all seems good. I have just re-squared the machine and it is now dead on. The voices in my head keep telling me it is a belt that is slipping.

1 Like

Are you using the homing switches?

No, I was never able to get the homing switches working. Different problem for a different day.

1 Like

Just checked my belt tensions. Both Y belts seem identical, which seems to kill my belt slipping theory.

Just made some home made spacer blocks and checked my positioning the way you described. There was quite a difference from left to right. I was quite surprised. Once I lined them up everything is tracking along the grid lines again. I’ll be ordering my 123 blocks shortly. Thanks Allen. You da man!!


I would suggest any CNC machinist, or really anyone working with any degree of tolerance have the following frequently used tools on hand:

  1. A decent inch/mm Scale, some people call them “rulers”. A good 100mm / 6in scale comes in pretty handy, and quite useful for a quick “eyeball” of measurements.

  2. Decent Calipers… Digital calipers seem to be the rage these days, but cheap ones aren’t very reliable. A decent set of digital, or manual calipers are a great investment, be it measuring thickness, width, or using them as a “marking” tool on harder materials, a good set will be used almost every time.

  3. 1-2-3 Blocks… So named because they are 1" x 2" x 3", A set of these blocks give you a precise machined surface to work off of. Be it placement, alignment, or clamping, they will serve a plethora of useful purposes.

  4. Clamping. Depending on your material, tolerances, and personal preference, you will almost always find clamps useful. be is C-Clamps for large pieces, or glue work, or toe clamps for holding pieces to your waste board or other fixturing surface, clamps are a MUST HAVE for any machinist.

  5. Vices… no… not the kind that get you a spot on COP’s tv show… Vices come in many flavors, the most common, and frequently used are the low profile fixed-jaw vices. This allow you to position pieces in the jaws rather than flat on the wasteboard, so you can get angles, and clerances not afforded by clamping. Another popular choice is rotary-table vices, for rotating your piece between operations without losing position.

  6. Files. No matter the project, or material, sometimes you just can beat a good set of files. Be it breaking the edge on a part, or cleaning up chamfers or fillets, files serve multiple purposes, and are quite handy.

  7. Shop towels. I can’t stress this enough. Clean is good. Dust, dirt, grime, chips, and refuse and clutter are a sure fire way to have an accident. They can cause parts not to be aligned, or clamped properly, cause parts to slip, or worse, cause a part to work free, and go flying towards your face!.. Not to mention the health hazards involved with tripping over clutter near a sharp rapidly spinning autonomous power tool… Be safe, clean everything!

  8. Finally, but most important. Safety gear. That means gloves, glasses, respirator, first aid kit, fire extinguisher, and anything else you can think of to save life and limb in the case of an accident. Some of the materials you may choose to put on your X-Carve may be flammable, toxic, or otherwise hazardous to your health. Plastics can be a serious health risk if it’s a toxic blend, or you inhale dust of fumes from it. Being safe should be your top priority, no matter how cool the work piece may be, in the end, you can only enjoy it if you’re healthy.

Yes, vices can get quite expensive. If you have access to a milling machine, you can make your own :slight_smile: The stock steel is usually relatively cheap, the most expensive part will be the leadscrew, unless you go with one that doesn’t use a lead screw.

That would get you in the ball park, but if you’re looking for something ultra-precise, you may want to just buy it, or if you do make your own, surface grind it, or find a local surface grinding service.

You should be able to find solidworks files on most vices, i know some kurt vices have them available.

oh… hehe… forgot to add something…

** 9) Squares and angles… You may or may not need the angles, but a decent square is a good addition to any toolbox. While you can, using complex maths and a good supply of patience, measure off of known surfaces to square a part up, it’s much faster and easier to use a precision square :slight_smile: Angles are great for when you need to tilt a piece to a common angle… i.e. 45 degrees… there are many types of squares out there some are even triangular and serve the dual purpose of both square, and angle, precision ground squares and angles, or square with angle are a great way to make setup of a part much faster.

The combo of clamps + 1-2-3 blocks + angles / squares means you can pretty much hold any part at any angle and machine it safely. I say “pretty much” because spheres are a complex object to clamp and machine (a lathe comes in handy here to create a flat surface to clamp against)