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Hook Spanners for Lock Nuts
Hook Spanners
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SKF HN 4-16 Hook Spanner Set
Hook Spanner Set
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Hook Spanners

A hook spanner is a curved wrench, usually terminating with a pin or hooked nose that locks securely into a groove in a ring nut or bolt head or into a radial hole in a bearing nut. This provides an easy means of securing a grip and excellent leverage. Fitting is quick and easy, even in confined spaces - such as between chain-rings - and some varieties are designed to withstand impact tightening and loosening if needed.

Hook spanners come in many sizes and with different profiles to match that of the components that need to be turn-locked or adjusted. Most hook spanner profiles are defined by standards such as DIN 1816 and HT0414.

Other specifications to consider are the desirable length of the arm and the preferred type of steel or other material. Our largest spanner is over three feet in length, with common materials and finishes including blackened tempered steel and nickel-plated steel. All our hook spanners have ground round edges for optimum grip and comfort.

Our current range consists of three main types:

  • SKF HN series lock spanners make it easy to apply the correct tightening torques to taper bore bearings and maintain the correct radial clearances. These spanners are suitable for a wide range of nuts, including KM, N, AN, KMK, KMFE and KMT types, and those that conform to DIN 981 or DIN 1804. These spanners are available individually or in a set of nine for lock nuts between size 4 and 16.
  • Our HN/SNL series are mostly used for mounting or dismounting tapered bore bearings on adapter sleeves in SKF SNL and FSNL housings; again, they are versatile and can be used with a variety of shafts and housings. They have a larger contact area on the nut than those above.
  • Our impact spanner series is designed with the strength and optimum elasticity of steel for robust and safe tightening and loosening of locknuts by applying a mallet. The materials and design minimise the risks of damage to the nut, shaft, bearing, spanner, and the person using it.

There are other types of hook spanner, including some that are hinged or spring adjustable, making them even more flexible and versatile on various kinds of bolt head, bearing collar, lock nut or other component. If you are interested in locating one of these more specialised variations, just give Simply Bearings a call and we will almost certainly be able to locate one for you.

Remember that we also offer same-day despatch and a free delivery services to many locations, and guarantee that all our products are of the highest quality.