Set clearance across the complete travel, not at one convenient position, and distinguish rail alignment from axial-roller adjustment.
Clearance belongs to the assembled guide
The radial roller, axial roller, mounting structure and profile all influence running clearance. A bearing that rotates freely on the bench can still bind after welding or bolting if the rails are not parallel, the profile twists under fastener load or the mounting plate is distorted.
Inspection sequence
- Inspect the rail contact surfaces for dents, weld spatter, scale and transport damage.
- Check the profile section and bearing family against the approved drawing.
- Support the rails in their final structure before checking parallelism.
- Move the carriage through the complete stroke and record the tightest and loosest positions.
- Adjust the designated bearing or mounting interface; do not grind a hardened running surface to create clearance.
Fixed and adjustable executions
Standard 4.05x bearings have fixed axial geometry, so clearance is established by the profile and mounting position. Eccentric 4.45x, screw-adjustable MR.96 and shim-adjustable designs allow controlled correction at the axial support. Adjustment should remove excessive play without creating preload or binding.
What to record
- Profile designation and actual cross-section measurements
- Rail straightness and parallelism over the working length
- Bearing model, suffix and adjustment position
- Clearance or free-running check at multiple travel positions
- Fastener torque, weld sequence and final carriage condition
Common failure patterns
Edge marking on one side of the radial roller suggests skew or poor support. A polished band on only part of the axial roller can indicate incorrect alignment. Tight spots at regular intervals often point to rail distortion around welded brackets or mounting fasteners. If the old rail is worn, matching a new bearing to the widest worn section can leave insufficient clearance elsewhere.
Use the profile matching table to identify the starting combination, then confirm the current controlled drawing before installation.
Technical note: This guide supports preliminary sourcing. Confirm the controlled drawing, tolerances, load capacity and application requirements before ordering or installation.