How to Adjust an Eccentric Combined Bearing

Identify the adjustment design first

Models in the 4.45x family normally use an eccentric axial arrangement. Other families may use an external screw, shims or an adjustable bearing unit. The tool access, locking method and available travel differ, so use the model-specific drawing rather than a generic adjustment procedure.

Recommended setup order

1. Install and align the structural rails before using the bearing adjustment to remove play.
2. Set all adjustable positions to a known starting point.
3. Move the unloaded carriage through the full stroke and locate the tightest rail position.
4. Adjust in small increments at the intended feature while checking free movement.
5. Secure the locking feature according to the approved drawing.
6. Repeat the full-stroke check unloaded and under a controlled test load.

Avoid preload by feel alone

A carriage that feels tight is not necessarily more accurate. Excessive adjustment can preload the axial roller, increase heat and accelerate wear. The correct target is the specified assembled clearance or the approved functional test, not the complete removal of perceptible movement at one rail position.

Signs that adjustment is masking another problem

• One position is free while another binds.
• The required eccentric position differs greatly between bearings.
• Axial rollers show edge contact.
• The carriage becomes tight after structural fasteners are torqued.
• Adjustment reaches its limit before acceptable guidance is achieved.

These symptoms justify checking rail parallelism, profile distortion, mounting-plate flatness and whether the correct bearing/profile combination was selected. Browse the adjustable combined bearing range or request the controlled drawing for the exact model.