Lock Nuts
Threaded nuts that hold a bearing, sleeve or coupling in position on a shaft. The family divides by how the nut is stopped from turning — a washer tab into a keyway, an integral clamping element, or a ground precision design for spindle work. SES holds the range as an authorised SKF distributor, covering thread range About M10 to over M1000 across the family; thread form Metric fine pitch, with inch equivalents available; drive Slotted for hook or impact spanner, or socket driven; locking devices MB and MS series washers, locking pins, clamping segments. Executions include lock nuts requiring a keyway, lock nuts with integral locking, precision lock nuts. It is specified most often into pulley and drum shafts using adapter or withdrawal sleeves and gearbox input and output shaft bearing retention. Every part is genuine SKF through official channels, with designation, specification and options confirmed against your duty before it ships — supplied from Kolkata and our branch network, with breakdown cover that does not sit in an inbox.
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Supplying India’s Industrial Names.
From integrated steel plants to power utilities and EPC majors — the works that cannot afford a counterfeit part specify through SES.
Function
Axial retention and sleeve drive-up
Thread
Metric fine on shaft or sleeve
Locking
Tab washer, keyway, integral clamp, or pins
Sub-types
Keyway, integral locking, precision
Where it runs.
You will find Lock Nuts in the parts of a plant where this particular duty actually occurs. In practice that means pulley and drum shafts using adapter or withdrawal sleeves, gearbox input and output shaft bearing retention, fan shafts with a bearing clamped against a shoulder, and equally machine tool spindle bearing stacks, pump shafts with threaded bearing seats, crusher and mill shaft assemblies. What links them is the duty rather than the machine name — function: Axial retention and sleeve drive-up. If your installation is not on that list it matters less than you would think: the operating condition decides the specification. Send us the load, the speed, the running temperature and the environment it runs in, and we will match it to the right execution in the SKF range and confirm what is in stock.
Specify it against the duty.
Specification here follows the operating condition, not the catalogue. The shaft already carries a standard keyway and the design is proven — The conventional nut and tab washer pairing. It is cheap, well understood, and every fitter on site knows how to lock and unlock it. Cutting a keyway would weaken a highly stressed or hollow shaft — A nut with integral locking. The stress raiser at a keyway root is a real fatigue risk on a heavily loaded journal, and the nut style is the easier thing to change. The assembly is a spindle where inner ring squareness controls the finish — A precision lock nut with a ground and lapped clamping face. A general purpose nut tilts the ring by a small amount, and that shows on the workpiece. Where two of those apply at once, specify for the harsher of the two — under-specifying is what puts the part back on the bench a month later. Send us the duty and we will confirm the execution.
Ordering this from SES.
Always tighten a lock nut against a bearing inner ring with the shaft supported, not against a bearing that is hanging in its housing. Pulling the nut up with the outer ring taking the reaction pushes the load through the rolling elements and dents the raceway before the machine has ever run.