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An SKF lock nut holds a bearing against a shaft shoulder or pushes it up its sleeve. These are slotted nuts with a fine thread, and they need some form of locking so they don't back off. The catalog covers metric and inch series, some locked with a washer and some with locking built in. The series tells you the thread and how it locks; the number tells you the size.
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KM 4 is the general-purpose metric nut. It is secured with an MB series lock washer carrying the same number; the washer has an inner tab that engages the shaft keyway and outer tabs that you bend into the nut's slots. N 05 is the inch-thread version and uses a W series washer. In both cases the number is a series size, not the thread diameter.
KMT 4 shares its nominal size with KM 4 but locks another way: no washer and no keyway in the shaft. Large sizes are covered by the HM series, for example HM 3044, which has a securing system of its own. Do not swap a nut for one from another series without checking the thread on the shaft.
The nut works with the shaft or the sleeve, and the threads have to match in both diameter and pitch. On an adapter sleeve, the nut and washer come as part of the set, so if you replace only the nut, identify the sleeve as well. On a threaded shaft end, the machined thread is what counts, and measuring it is worthwhile when there is no drawing.
Look at the washer when you take things apart. A sheared inner tab, or outer tabs fatigued from being bent several times, mean the washer should be replaced along with the nut. Use a hook spanner or impact spanner of the right size to tighten and loosen; driving a punch into the slots deforms the nut and makes the next removal harder.
Give us the full designation and quantity, and say whether you also need the lock washer. If the marking can't be read, measure the thread diameter and pitch, the nut's outside diameter and width, and count the slots. Include the designation of the bearing or sleeve it goes with and whether the shaft has a keyway. With that we can confirm the series and size.
They have the same nominal size but a different locking method. Check the shaft before you change series.
An MB series washer with the matching number, ordered under its own designation.
No, it is a series size. Confirm the thread by measuring or in the manufacturer's catalog.
Can't find the exact model? Tell us the part number or model you need. We'll track it down and quote it, whether or not it appears in our catalog.
The SKF KM series lock nut is used to secure bearings on shafts, allowing controlled adjustment during mounting and maintenance. It works together with a lock washer to hold the bearing in position. This nut is common in power transmission assemblies where axial movement must be limited.
When a bearing with a tapered bore needs to be held firmly on a shaft, the SKF KMT series lock nut provides precise adjustment and dependable retention. Its design simplifies both installation and removal, which helps keep rotating equipment serviceable.
The SKF HM series lock nut is a precision fastening component designed to hold bearings and other shaft-mounted parts in place. It features a metric thread and slots for a hook spanner, allowing secure and adjustable tightening. This makes it a practical choice for industrial settings where dependable and straightforward installation is required.
Example part numbers:HM 30/530HM 30/710HM 31/500HM 3044HM 3048
The manufacturer part number is all we need: we'll quote it and share dimensions and equivalents via WhatsApp or email.
