KMT and KMTA precision lock nuts

KMT precision lock nuts have slots around their circumference to accommodate a hook or impact spanner . The designations of the appropriate spanners are listed in the technical specification for each product of the product table. For additional information about the appropriate spanner, refer to Bearing fitting tools. KMT precision lock nuts with a thread ≤ 75 mm (sizes ≤ 15) have additionally to the slots two opposed flats to accommodate a spanner. Those lock nuts with a thread ≥ 80 mm (sizes ≥ 16) have six slots and no flats.

KMTA precision lock nuts have holes around their circumference and in one side face. They can be tightened with a pin wrench or a pin-type face spanner. Appropriate spanners in accordance with DIN 1810 are listed in the technical specification for each product.

KMT and KMTA precision lock nuts are designed for frequent installation and removal (provided they are not damaged).

Installation

1. With the bearing in position, screw the lock nut into place.

2. Tighten the nut with a hook or impact spanner making sure not to over tighten it.

3. Tighten the set screws carefully until the locking pins engage the shaft thread.

4. Tighten the set screws alternately with a torque wrench until the recommended torque value is obtained (see technical specification for each product .

KMT and KMTA precision lock nuts should not be used to drive a bearing up onto a tapered seat.

Adjustment

KMT and KMTA lock nuts are adjustable. The three, equally-spaced locking pins enable these lock nuts to be accurately positioned at right angles to the shaft. However, they can also be adjusted to compensate for slight angular deviations of adjacent components.

Adjustments can be made using the following procedure:

1. Loosen the set screw(s) at the position showing the greatest deviation.

2. Tighten the remaining screw(s) equally.

3. Retighten the screw(s) that were loosened.

4. Check that the alignment of the nut, relative to the shaft, is currently as required.

5. Repeat the procedure if necessary.

Removal

When removing KMT and KMTA lock nuts, the locking pins can still engage the shaft thread even after the set screws have been loosened. Using a rubber hammer, tap the nut lightly in the vicinity of the pins to loosen them.

Lock nuts requiring a keyway are easy to install. Each nut is provided with four or eight equally spaced slots around their circumference to accommodate a hook or impact spanner. The designations of the appropriate spanners are listed in the technical specification for each product of the relevant product table. For additional information about the appropriate spanner, refer to Bearing fitting tools.

Lock nuts requiring a keyway can be reused, provided they are not damaged. A new lock washer, locking clip or locking plate should be used each time the corresponding lock nut is reinstalled.