Support Unit Selection & Mounting (BK / BF / EK / EF / FK / FF)

1. Fixed end vs supported end

The fixed end (BK / EK / FK) carries the full axial force, radial force and bending moment — use a zero-clearance or preloaded bearing and lock it reliably. The supported end (BF / EF / FF) gives radial location and rotation support, allowing slight axial float for thermal growth.

2. Select by shaft diameter

Match the bearing speed rating to the screw's top rpm; keep overhang short to limit deflection.

3. Mounting & alignment

• Keep the housing bottom flat and fully seated on the frame — no forced tightening that distorts the housing.
• Screw-to-rail parallelism ≤ 0.02 mm/m prevents eccentric load and abnormal wear.
• Tighten the lock nut symmetrically and step-by-step to the reference torque.
• In dusty / chip environments add a cover to extend bearing and screw life.

4. Related technical guides