GT3 Backslash problem - VIDEO


I replaced gt2 belt with GT3 3 mm pitch 3mm. now i have a problem with 0.5mm backslash.

VIDEO youtube

Do I try to replace a pulley or belt?
Any advice or help?


Looks more like a calibration issue.

If the belts have been stretched, you’ll see that. Maybe an upgrade to belts with a steel core if you’re looking for that level of precision.

What do you mean?

Tell X-Carve to move spindle in X Y or Z direction, it should move exactly 22mm if you tell it to move 22mm. Moving back and forth only 21mm instead will give the results your video showed there the roller wasn’t turning all the way back to the exact same spot. It appeared to be just a bit ‘short’ of the intended distance.

There’s lots of threads here about how to calibrate your machine.

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Problem is backslash o pulley. I try replace new belt and problem is not fixed. I try also belt tension, am remove idlers amd add one bearing…but all without good result. This gt3 is crap…

Did you install new GT3 pulleys at the same time as the belt and got this much backlash?

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Thx for replay. I changed the belt and pulley. All parts is are from the same supplier - china :slight_smile:

@Traxxtar This wouldn’t be a steps per mm setting. Regardless of the distance the axis moves, it should (ideally) return to the exact same spot when told to move a distance and then back the same distance.
When the pulley changes direction, any “slop” in the interface between pulley and belt will show up as backlash before the teeth fully engage again.

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