Shenhui Torque Tube Pulley has come loose

[Nick Foley]

After the X gantry collided with a workpiece, it was clear that my system was out of alignment. After poking around, I noticed that the back-left pulley on the left Y belt (the one connected to the left end of the "torque tube") was spinning freely on the torque tube.

Unlike every other pulley I've used, however, this one doesn't seem to have any sort of set screw or keyway. It just appears to have been (poorly) press fit onto the end of the torque tube.

After some light disassembly, I now have the pulley in my hands and it is clear that there was nothing holding it in place, other than maybe some initial friction that has now been broken.


Any suggestions on how to solve this problem? Seeing how this is assembled, I can't possibly be the first person this has happened to.


I could order another pulley that has a proper clamping mechanism, but what is the tooth profile? Is it GT2? It appears to be 3mm pitch and an 8mm bore.

[Rich Harman]

I had mine come loose but for a different reason. On mine the pulley is secured with two set screws. You can't see the set screws until you get the belt off. Apparently they had drilled all the way through the axle creating a weak point and the end of the axel snapped. The end of the axel is turned down to accept the pulley. I cut the end off, bored a hole into the end of the solid axel and then installed a steel rod that I had already turned down to accept the pulley. I undersized the hole so that the only way to put it in was to heat up the axel and pound it in. Works great, better than new.

It never should have happened in the first place. Quality control is lacking on these machines for sure.

[Rodne Gold]

I would inform the factory of this ..they react quickly to any mechanical issues and will correct this in new builds