Lock nuts with integral locking

Lock nuts with integral locking reduce the cost of the shaft as no keyway is required. Installation is quicker and easier because no separate locking device is necessary.
KMK lock nuts

KMK lock nuts (fig. 1)

  • have a threaded steel insert in their bore to lock the nut in place on the shaft or adapter sleeve
    • The threads on the insert match the lock-nut threads.
    • The insert acts as a pressure plate when a grub screw, which runs through the body of the lock nut, is tightened (fig. 2).
  • are intended to locate radial bearings in less demanding applications

KMK lock nuts should not be used on shafts or adapter sleeves with keyways or key slots. Damage to the locking device can result if it aligns with a keyway or slot.

KMFE lock nuts

KMFE lock nuts (fig. 3)

  • are designed to locate CARB toroidal roller bearings, sealed spherical roller bearings and sealed self-aligning ball bearings axially on a shaft
  • have appropriate contact faces for the intended bearings
  • are available for thread M 20x1 to M 200x3 (sizes 4 to 40)

KMFE lock nuts should not be used on shafts with a keyway. They should only be used with special adapter sleeves with a narrow slot. Damage to the nut is likely if one of the grub screws aligns with a keyway or wide slot. KMFE lock nuts can be reused, provided they are not damaged.

Features and benefits

  • Maximum axial run out locating face to thread 0.020-0.030
  • No keyway required
  • Simple to install
  • Simple and robust locking
  • Reusable
  • KMFE has appropriate contact faces for intended bearings
  • KMFE is equipped with visual marks for the use of tightening angles

The locking principle

KMFE (fig. 4) lock nuts have one integral grub (set) screw, to lock the nut in place. When the grub screw is tightened, it causes the nut thread to deform and press against the shaft or sleeve thread. The resulting friction is sufficient to lock the nut in place.
SKF logo