The same Z axis belt slipping.....?

Hi there!

it was few moths i was unable to work with my shapeoko XXL…yesterday i was back on the machine to run (finally) the dog holes project :slight_smile:

Unfortunately the Z belt slipped back…then i set the tension as we usually do :slight_smile:

But there is no way to solve this!!! i set the tension 5 times but the Z axis slips always and i can’t understand why…

Here a video of what happend

I’ve already wrote to the support but i would share also with you :slight_smile:slight_smile:
Someone has ideas?

Possibly an out-of-spec belt — there was a run of them, then we switched to 520mm.

We’ve discussed an Acme screw upgrade — another option would be a linear slide, but that then gives up the wonderful safety aspects of belts (a crash just skips teeth rather than damaging the machine).

When I replied, I suggested that one could try adding a pair of M4 nuts as “jam” nuts to secure things — that said, the Z-axis is tricky to get right at first (at least that’s my experience) and requires a bit of fiddling, patience, and acquired familiarity.

I’ve had issues when trying to cut way down at the furthest extent, and the springs being too strong. You might try taking off one of the springs and seeing if that helps.


Was there a discussion about putting limit switches on all of the extents of all axis/rails?
Just if, for example, the extent settings in software are for some reason not adhered too?

Not a discussion per se. Some of the 3rd party kits, Tim Foreman’s for example do this.

It’s also discussed somewhat on the wiki:

I thought the same, so i’ve tried to cut a “normal” piece of wood on the wasteboard to reduce the extension of the z axis…but it happened the again :frowning:

Just to review, Z-axis problems:

  • out-of-spec belt — contact and we’ll replace
  • insufficient belt tension — use small pry bar (carefully) on old style plates, careful not to bend motor shaft — think guitar string tight
  • trying to reach down too far w/ new style plate — lower router or add a spoilboard
  • springs too strong, try removing one

Hopefully those things will help — if not, contact

OK, maybe that was it. Thanks for the info!