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SKF lock nuts hold a bearing against a shaft shoulder or drive it up its sleeve. They are slotted nuts with a fine thread that need a locking system so they do not work loose. The catalog includes metric and inch series, with a washer or with built-in locking. The series defines the thread and the way of locking; the number, the size.
See all SKF bushings and sleeves references →SKF guide →Lock nuts from all brands →SKF plain bearings →SKF adapter sleeves →
KM 4 is the general purpose metric nut. It is locked with a washer of the MB series with the same number, which has a tongue for the shaft keyway and tabs that are bent into the slots of the nut. N 05 is the version with an inch thread and takes a washer of the W series. In both, the number is a series size, not the thread diameter.
KMT 4 has the same nominal size as the KM 4 and another way of locking: it uses no washer and needs no keyway in the shaft. For large sizes there is the HM series, such as HM 3044, with its own securing system. A nut is not replaced by one from another series without checking the shaft thread.
The nut works together with the shaft or the sleeve, and the thread must match in diameter and pitch. On an adapter sleeve, nut and washer come with the set; if only the nut is replaced, the sleeve has to be identified. On a threaded shaft end, the machined thread rules, and it is worth measuring it when there is no drawing.
When dismantling, look at the washer: a sheared tongue or tabs fatigued by being bent several times are reason to replace it together with the nut. Tightening and loosening call for a hook spanner or impact spanner of the right size; a punch on the slots deforms the nut and complicates the next dismantling.
State the complete designation of the nut and the quantity, and whether you also need the locking washer. If it cannot be read, measure the thread diameter and pitch, the outside diameter and the width of the nut, and count the slots. Add the designation of the bearing or sleeve it works with and whether the shaft has a keyway. That confirms the series and the size.
They share the nominal size but lock differently. Check the shaft before changing series.
The MB series washer with the same number. It is ordered under its own designation.
No. It is a series size; the thread is confirmed by measuring or with the manufacturer's catalog.
Can't find the exact model? Write to us with the part number or model you're looking for: we'll find it and quote it, even if it's not listed in the catalog.
The SKF KM series lock nut is an essential component for mounting and securing bearings on shafts. Its design allows precise and secure adjustment, facilitating the installation and maintenance of transmission systems. Manufactured with high-quality materials, it guarantees durability and resistance in demanding industrial applications. It is compatible with a wide range of bearings and is used together with lock washers to secure the bearing position on the shaft.
The SKF KMT series lock nut is a precision component used to secure bearings with a tapered bore to shafts, with safe retention and exact adjustment. Its design allows simple mounting and dismounting, making maintenance of rotating equipment easier. It is ideal for applications requiring reliable and repeatable retention.
SKF N series lock nuts are the inch version of the well-known KM nuts: they secure a bearing on its adapter sleeve or at the shaft end, and are locked with a W series lock washer of the same number. They are used in machines and housings of North American origin, where the shaft and adapter sleeve come in inch sizes.
Just the manufacturer part number is enough: we will quote it and provide dimensions and equivalents via WhatsApp or email.
