Quote Originally Posted by fred_dot_u View Post
The vertical travel appears to be within the belt, not the pulley. Either way, it's the horizontal action of the mechanism that matters. Have you experienced artifacts in the print that you think may be caused by this travel? Generally speaking, I'd expect that this is not a factor of concern.
Fred, when I took the video, I hadn't even powered it up yet. I was finishing up the build.

Well I found the problem. The one thing that fixed the problem was just tightening the dang pulley itself. I guess when there's tension on the pulleys, there was enough play that caused it.

Things I tried that didn't help. The number #1 thing that shocked me, because it made the problem worse was adjusting the pulley on the motor. That pulley sits about a 1/4 inch lower, in relationship to the frame, as this pulley. When I moved it to match, it made the problem way worse.

What made me think it was the actual pulley the belt was riding up and down on.. Well, I had check the angles on it without the belts on. I tried shimming it, which made the problem worse.. sometimes in the opposite direction, blah, blah, blah, then I just started messing around with belt tension. I took the belt in my hands, and just pulled back and forth to see what happened... I tried different positions as in in holding the belt slightly high than my right and what not. Tried more tension and less tension. I just wanted to see what happened based on belt tension and angles. That's when I had the light bulb moment. I noticed the less belt tension, the less vertical movement. At that point, I took an allen wrench and just tightened the center bolt by a 1/4 turn. put the belt back on and bam! then problem was like 50% less. I gave it another turn and checked and it was fixed.