Bind on X axis

Hello All,

Hoping someone can help. I recently finished my Primo build but it’s giving me an issue. When the core is at or around the home position on the Y, when I move down the X axis, the front motor will catch for a split second. This catch or bind is enough to get the two X motors no longer in sync with each other.

I have double-checked the square of the frame, I have rotated to rail in case they are not straight, I have tightened belts and loosened belts, and I have tried loosening and tightening the truck bolts. The core seems tight with no wobble. I feel like i have exhausted most options.

build size is about 17x20 inches.

Anything else you guys suggest I try?

thank you

I had some weird issues like this early in my build. It turned out to be a screw holding the stepper motor on had backed out a bit and was rubbing on a pulley causing it stall. Maybe check those small stepper screws on that truck and make sure they haven’t backed out?

Maybe the pulley is slipping? Did you loctite your grub screws?

Thanks for the reply.

I double checked the screws holding the stepper and they are tight.

I also double checked the grub screws, both are tight. No lock tight on them though.

It seems to bind at the same place each time. Also if I move the core up along the y, it doesn’t bind on the x.

Can you manually move it and feel the catch?

So I disconnected the belt and removed the tube that connects to the core. When moving the truck side to side on the x I found that it was loose and freely moved in the middle, and supppper tight on either ends. I got my caliper out and found that the pipe was not uniform in thickness. So I took some 400 grit sand paper, then some 220 followed up with some wax. It’s now buttery smooth and has not binded yet. Tonight I’m going to do the same the other five rails.

Thank you!

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After sanding down all 6 rails, the machine moves so much smoother. I guess that is what I get for using normal box store conduit instead of Stainless Steel.

Thanks all for the help.

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I just recently did the same with my box store EMT and it makes a large difference to take off that galvanization. I went for 120 to 220 to 320 and it’s smooooooth now. I even went a step further. There were still some spots I could feel the plastic want to grab to so I grabbed some baseball glove butter I had laying around and gave all of the rails a light coat. Slicker than you know what now.