Sticky Z assembly

I’m finally getting around to assembling my machine and the Z axis is not smooth. It binds up and sounds like sandpaper as it slides back and forth. Similar to the one in part 1 of the v2 assembly video. Any ideas? I may partially dismantle the assembly to check that the trucks glide smoothly individually.

If I loosen the eight screws (4 on each truck) it will move smoothly. If I tighten 4 screws on one truck only it moves smoother but not perfectly. Soon as loosen one side with the other tight it snags again.

I flipped the smaller plate over and it’s better. But it still binds up on the notched end but not as bad.

Bill, try loosening the anti-backlash blocks a hair. It’s hard to figure out when they’re tight enough, but as long as you don’t see a delay in movement when you switch directions while turning the screw by hand you’re good.

Do I have a V2 or V3 Longmill. Shipped in June. I’m on page 21 and 22 And the photos don’t match the parts. I wish I could attach a photo.

Well the Z axis is assembled but I was unsure of the placement of the Z anti-backlash nut. It doesn’t match the photo but it works so it must be right.

Is it the linear rails that feel tight? Let the rails run free and slide it back and forth for a minute by hand and it should loosen up a bit.

My gantry assembly looks like yours and is assembled the same way, backlash nuts in the same location and orientation. Other than needing a replacement X-axis rail and some V-wheels, my LongMill works, so I think you are on the right track.

I ran into a problem assembling the X axis where a few of the holes for attaching the end caps would not thread the M8 bolt. The bolt would thread in from the rear but not the front. It seems like many of the threaded holes are not cleaned up very well preventing threading a bolt.

Tomorrow I have to remove the stepper motor to get to the coupler because the threaded rod will not go in.