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Lock nuts requiring a keyway

KM, KML, HM .. T metric lock nuts

KM and KML lock nuts

  • have metric threads (fig. 1)
  • are designed to be used with lock washers
  • have four equally spaced slots located around their circumference to accommodate a hook or impact spanner (fig. 2)
  • are also referred to as shaft or withdrawal nuts
  • are available for thread M 10x0,75 to M 200x3 (sizes 0 to 40)
  • can be locked with either the MB lock washer (fig. 3) or with a stronger, MB .. A lock washer

    KML lock nuts have a lower sectional height than KM lock nuts.
HM .. T lock nuts
  • have metric trapezoidal threads
  • are also referred to as removal nuts
  • are available for thread Tr 210x4 to Tr 280x4 (sizes 42 to 56)
    For some sizes, no lock washer is available because these nuts are intended to dismount bearings with a tapered bore from a withdrawal sleeve.

KM, KML, HM…T lock nuts can be reused, provided they are not damaged. A new lock washer should be used each time the corresponding lock nut is installed.

Features and benefits

  • Simple, stable and reliable fastening
  • Wide range of sizes
  • Easy to install and remove
  • Thread diameters range from 10-280 mm
N and AN inch lock nuts

N and AN inch lock nuts (fig. 1)

  • using a lock washer (fig. 3) are available up to and including size 44 (thread diameter 8.628 in.)
  • using a locking plate (fig. 4) are low-profile-series lock nuts for nominal thread diameters ranging from 9.442 to 37.410 in. (sizes N 048 to N 950)
  • have four, equally spaced slots around their circumference (fig. 2) to accommodate a hook or impact spanner
  • are also referred to as shaft or withdrawal nuts
  • N 00 to N 14, AN 15 to AN 40 and N 44 lock nuts are normal series lock nuts commonly used together with bearings in the 12, 13, 222, 223 and 232 series up to size 23244, mounted directly to the shaft or via an adapter sleeve.
  • N 022 to N 044 lock nuts are low-profile-series lock nuts commonly used together with bearings in the 230 series. They can also be used to secure other bearing types and other machine components.
  • N lock nuts with a locking plate are commonly used with bearings in the 23048, 23148 and 23248 series and larger, but can also be used to retain any suitable bearing or other machine component.

N and AN lock nuts can be reused, provided they are not damaged. A new lock washer or locking plate should be used each time the corresponding lock nut is installed.

Features and benefits

  • Simple, stable and reliable fastening element
  • Wide range of sizes
  • Easy to mount and dismount
  • Lock washers available for thread 0.391 to 8.628 in. (sizes 00 to 44)
  • Locking plates available for thread 9.442 to 18.894 in. (sizes 048 to 096) and for thread 19.682 to 37.410 in. (sizes 500 to 950)
HM and HME metric lock nuts

HM and HME 30 and 31 series lock nuts

  • have metric trapezoidal threads (fig. 5)
  • have eight, equally spaced slots located around their circumference (fig. 6) to accommodate an impact spanner
  • are located on the shaft by MS locking clips (fig. 7).

When compared to HM lock nuts, HME lock nuts have a recessed side face to accommodate axial displacement of CARB toroidal roller bearings (fig. 8).

HM/HME lock nuts can be reused, provided they are not damaged. A new locking clip should be used each time the corresponding lock nut is reinstalled.

Features and benefits

  • Simple, stable and reliable fastening element
  • Wide range of sizes
  • Easy to install and remove
  • Available for thread Tr 220x4 to Tr 1120x8 (sizes 44 to /1120)


The locking principles

Lock washers, locking clips and locking plates are simple, stable and reliable fastening elements.

  • Lock washers (fig. 3) engage a keyway in a shaft, or adapter sleeve thread. The washer locks the nut in position when one of the washer tabs is bent into one of the slots on the nut’s outside diameter (fig. 9).
  • Locking plates (fig. 4) engage a keyway in a shaft or adapter sleeve and are attached to the side face of the nut by two bolts secured with locking wire. A locking plate consists of a plate, two hexagonal head bolts with drilled heads and lock wire to secure them (fig. 10).
  • MS locking clips (fig. 7) engage a keyway in a shaft or adapter sleeve and one of the slots in the outside diameter of the lock nut. Locking clips are attached to the nut by a bolt (fig. 11).
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