LR3 leadscrew coupler problem and solution

LowRider CNC Troubleshooting
1

Hi everyone. I noticed this problem when building my machine, the leadscrew coupler fully compresses when the core is all the way on that side, leading to inaccuracies in the z height. If you dont have this problem, its probably cause you have the lead screw touching the stepper shaft, which does hinder its ability to do its job properly (allowing for slight misalignment)

I have come up with a solution which is used for 3D printers, placing a ball bearing between the stepper shaft and lead screw, Allowing for a smooth full range of motion with no binding. However usually a decent size ball bearing is used to stop it wiggling around in the coupler, we cannot because it wouldnt leave enough lead screw in the coupler for the grub screws to grab it. The awnser is a very small ball bearing, from a spare bearing that we used for the build. but we must keep this centered on the shaft somehow.

Heres my solution, a 3D printed spacer that the ball bearing presses into, which then stops it from moving off the center of the stepper shaft. Super easy!

Unfortunately i deleted the stl i made for it, but its really easy, you guys got this :+1:

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20240513_1138241920×2560 629 KB

3 Likes
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Elegant solution. I hadn’t seen that before. Could the right size O-ring accomplish the same goal? Maybe even without the ball bearing?

1 Like
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Cool idea.

Since an O-ring is kinda squishy I don’t think it would be as effective as the ball bearing.

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I think an o ring would slip away from the ball bearing far to easily, and an o ring by itself wouldnt be very effective. It needs to have a tiny point of contact right in the middle of the lead screw to have a smooth motion