If the belt is slipping at any point, you need a belt tensioner which has teeth (and ideally a spring to provide force).
Hi Coleman,
Here’s the final version. The video size is bit large as I haven’t compressed it.
Thanks for your help. I’m controlling the motion with two switches.
Do you have any suggestions? The motors are little bit noisy due to improper mounting. I couldn’t find right screw length and haven’t cut the screw to avoid damaging it.
dl.dropboxusercontent.com/u/444 … 1%20PM.mov
Thank you very much for your help. 
Could you upload the video to your YouTube page and make it public?
youtube.com/watch?v=OZEr6aPQrXg
I’ll make a better video later on. The stepper driver just fried this afternoon.
It seems to be working well actually - not sure what you need advice about?
Hi Coleman,
I purchased two stepper drivers from robotshop.
One of the stepper drivers is not powering at all. Could you please help??
Sincerely,
bluehawk
We need much more information in order to help you troubleshoot - as many details as possible.
Do you have another, identical stepper driver which is working correctly? If so, can you use this one in its place with identical connections and see if it works?
If it does work, then either your connections to the controller, the power or the code is not correct.
The other stepper is working just fine. I noticed voltage regulator is getting hot when I connect the power source.
Edit: I have motor disconnected for testing purpose. Only M+ and GND connected to 18V 2Amp power supply.
If you are using only one 2A power supply for everything, that may be one of the issues. Did you contact us via the support center too?
Yes! I have opened a ticket. I’m not using full power at all. maybe 1 amp in total.
What if your second belt/pulley system rotates at the same speed as the one used to move the traveller along the X-axis? This would mean that when both are moving at the same speed, the Z-traveller does not move. When you stop the X-traveller and move the second pulley system, the bevel gear would rotate, causing the Z traveller to move.
Just an idea.
For the bevel gear not to rotate while motor 1 is in operation, motor 2 will also need to be in operation in the same direction. In the image you have both the top and bottom of the bevel gear in contact with the second timing belt (timing belt associated with motor 2), but in reality is should only be one side, allowing it to move linearly but not rotate.
Wouldn’t the bevel gear rotate since they’re attached on the internal gear on the belt (on left side).
Here’s the picture…
The rod will need to be disengaged when there is motion in y axis and then engage with the bevel gears. It seems the one plausible solution to me.