Shaft Mounting Instructions for Set Screw-Locking Insert Bearings

For set screw type housed spherical ball bearings under ordinary operating conditions, simply fasten the two hexagon socket set screws to the shaft with a hexagon socket wrench. Tighten the tip of each set screw until it slightly indents the shaft surface as required.

For the shaft area contacting the set screws, two machining methods are recommended:

Machine a flat surface on the shaft (Figure 1)

Machine a concave recess on the shaft (Figure 2)

For applications subjected to vibration, shock loads, or heavy axial loads, use a stepped shaft secured with a lock nut as shown in Figure 3.

Tighten the set screws in accordance with the recommended tightening torques listed in Table 1.

Figure 1: Flat machined surface on shaft for set screw contact

Figure 2: Concave recess machined on shaft for set screw contact

Figure 3: Locking arrangement using stepped shaft and lock nut

Table 1 Recommended Tightening Torques for Set Screws

Excessive tightening torque on set screws will impair bearing rotational accuracy and may cause cracking of the bearing inner ring. Insufficient torque will allow relative rotation between the inner ring and shaft during operation, resulting in loose mounting. Therefore, set screws must be tightened to the appropriate torque values specified in Table 1.

Specially hardened bearing units mitigate the drawbacks of fully hardened inner ring products, significantly reducing inner ring cracking and set screw loosening risks. These units maintain secure bearing fixation to the shaft even under repeated cyclic loads with frequent vibration and shock.

Mounting Procedure for Set Screw Type Housed Spherical Ball Bearing Units

1. Check that the set screw tips do not protrude into the bearing bore. Loosen the set screws if they extend inward.

2. Slide the bearing unit smoothly onto the shaft and position it at the mounting location. Avoid twisting the unit; never strike the side of the inner ring or the oil seal ring directly.

3. Secure the bearing housing firmly to the machine base. Use a sufficiently rigid base with flatness that meets mounting requirements to prevent housing deformation during installation.

4. Tighten the two set screws evenly to the torque values specified in Table 1 using a hexagon socket wrench.

2026 July 1st Week FK Product Recommendation

Insert Bearings：

Insert bearings (SKF Y-bearings) are based on sealed deep groove ball bearings in the 62 and 63 series, but have a convex outer ring and in most cases an extended inner ring with a specific locking device, enabling quick and easy mounting onto the shaft.