Cookies on the SKF website

We use cookies to ensure that we give you the best experience on our websites and web applications. By continuing without changing your browser settings, we assume you give your consent to receive cookies. However, you can change your browser cookie setting at any time.

Installation and removal

KMT precision lock nuts have slots around their circumference to accommodate a hook or impact spanner (fig. 1). The designations of the appropriate spanners are listed in the product table. For additional information about spanners, refer to the catalogue SKF Maintenance and Lubrication Products or visit Maintenance products. In addition to the slots, KMT lock nuts with a thread ≤ 75 mm (size ≤ 15) have two opposed flats to accommodate a spanner.
KMTA precision lock nuts have holes around their circumference and in one side face (fig. 2). They can be tightened with a pin wrench, a pin-type face spanner or a tommy bar. Appropriate spanners in accordance with DIN 1810:1979 are listed in the product table.
KMT(A) precision lock nuts are designed for frequent installation and removal (provided they are not damaged).


KMT and KMTA precision lock nuts should be locked in two phases:
  1. Tighten the grub (set) screws carefully until the locking pins engage the shaft thread.
  2. Tighten the grub screws alternately with a torque wrench until the recommended torque value is achieved (→ product tables for KMT and KMTA).


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 (fig. 3 and fig. 4):
  1. Loosen the grub 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 now as required.
  5. Repeat the procedure if the result is not adequate.


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