04. Linear Rail Troubleshooting guide

Written By: Rat Rig (and one other contributor)

Steps

Introduction

Use this guide if the motion on your linear rail is not perfectly smooth.

Take a paper towel and carefully wipe the rail. Move the carriage to allow you to clean the rail fully. Make sure you scrub off any small particles that may have gotten lodged in the thin grooves on each side of the rail.
Test the smoothness of your carriage by applying a small amount of pressure on it and moving it with your fingers.
Letting the carriage slide under its own weight is not a good test, as linear rails are designed to work under load.
Problem solved? If not, jump to the next step.

Slightly unfasten the 4 screws on the sides of the carriage, without removing them. This will give the ball bearings inside a bit more room to adjust their position.
Slide the carriage back and forth so all parts in the assembly settle in the best position.
Fasten the carriage screws again.
Do not apply pressure on the carriage when you're tightening.
Do not tighten too much.
Tap your carriage very lightly using a mallet (soft hammer). Tap on every face of the carriage, and on every corner of each face. This is to make sure that any stubborn ball bearing falls into the right position.
Test the smoothness of your carriage again.
If the problem persists even after a couple of tries, jump to the next step.

CAUTION: a disassembled carriage can easily start dropping ball bearings. Handle it carefully, and read the instructions until the end before starting.
Remove one of the end caps of your linear rail by pulling it out.
Turn the rail upside down.
Carefully slide the carriage out of the rail.
Check if the amount of ball bearings on both cavities of your carriage is the same.
Each cavity should be filled with bearings, with some left-over space. Without removing them, separate 2 ball bearings and make as wide a gap as you can between them. The left-over space should be approximately as wide as one ball bearing. If you find a gap wider than this, your linear rail is missing ball bearings.
If the ball bearings are looking good, lubricate your carriage.
If after lubrication and reassembly, your rail is still not smooth enough, try to swap the carriage with another rail, in order to pinpoint if the issue is in the carriage, or in the rail. Please contact our support.