Adjusting the PRS Z-Axis Bearings • October 17, 2016
© Copyright 2016 ShopBot Tools, Inc.
page 3
Introduction
This document describes how to adjust the bearings on the Z-axis captured rail type of PRS tools.
The PRS Z-axis has been calibrated before leaving ShopBot. However the bearings on the Z-axis may
need to be adjusted after a period of use or unexpected stress. Here are some of the possible issues
and how to adjust them.
Test the Z-Axis Response
Turn off ShopBot power. Push the Z-axis down and release it. Normally, it should move upward under
spring tension. The presence of a spindle or air drills may affect the speed and distance of this motion,
but the overall movement should be smooth and fluid.
Bearings are too loose
if
• Top and/or lower bearings spin freely and are not in contact with inner part of the captured rail.
• There are lateral inconsistencies in Z-axis (commonly called “slop”).
Bearings are too tight
if
• Z-axis loses steps/position, binds or even stops abruptly.
• There is premature wear to the inner part of the captured rail.
If the Z-axis moves smoothly, and none of the above issues are present, then the bearings do not
need adjusting.
