XCarve backlash X-Axis >> Y-Axis

Does anyone know why the backlash is much higher on the X-Axis than the Y-Axis? I measured the backlash on my 500x500mm machine, and for the Y-Axis, the backlash is about 0.002", but the X-Axis has a backlash of 0.008" - 0.010". These numbers seem to be confirmed by other people measuring them as well (google is your friend :slight_smile: ). Is it because the X-Axis has a single belt vs 2 belts on the Y-Axis, and we are seeing the belt stretch? (both belts are properly tensioned).

I ended up adjusting for it by using the backlash compensation in LinuxCNC, but I would like to fix the mechanical side to get the X-Axis backlash lower. Anyone have any thoughts (I’m tempted to order a ballscrew from China to replace the belt drive on the X-Axis)? I can live with the 0.002", but I’d like to get the X-Axis the same as the Y.


You upgraded your spindle? What’s it weigh? You may need to upgrade from the 2GT to the 3GT belts. But first check that your set screw hasn’t come loose a bit.

The belts are properly tensioned when I measured the backlash. The backlash was measured as per http://www.cncexpo.com/MeasuringBacklash.aspx.

Cutting circles out of 6061 Aluminium for a 13mm bearing mount made ovals that have a diagonal axis. (I’m using an upgraded 0.8Kw water cooled spindle at 18000 RPM with a 1/8" 3-flute carbide end mill, cutting 0.005" depth of cut at 15 IPM).

I managed to get a perfect (well, close enough – at least it is circular and not oval) circle today after putting in the backlash compensation for the backlash I measured into LinuxCNC (I gave up on the chilipepper / grbl route and went for the G540 / LinuxCNC on old parallel port computer).

It’s just weird that the backlash is different and so much larger (4x) for the X-Axis than the Y-Axis. I would have thought that the backlash would be the same, or 2x (since there is only one belt).

That’s why I suggested looking at the obvious first. That spindle is heavier that the what the X-Carve was designed for. Slinging around more weight on the X axis could be producing more “give” in the parts operating it. Granted I’m not a mechanical engineer lol. But it makes sense to me anyway. I know people were having more issues with flex just going from the quiet cut spindle to the Dewalt 611.