51330-M bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-28

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the 51330-M model number is decoded

The 51300 series order number 51330 M is a SKF single-direction thrust ball bearing for a 150 mm seat, built to ISO 104, with a flat housing seating surface, 150×250×80 mm boundary dimensions. Three separable parts make the set: the tight-bore shaft washer that locates on the shaft, the loose-bore housing washer in its register, and the ball-cage assembly; load is purely axial and acts in one direction. reading 51xxx as a code: the 1 after 5 identifies one load direction and a flat seat, and the next digit ranks the section 1 (light) to 4 (heavy) before the two-digit bore code. bore code 30 decodes to 150 mm (code 30 × 5) under the same 00/01/02/03-exception, ×5 rule SKF uses across its coded bearing ranges. the trailing M names a solid machined brass window cage centred on the balls rather than on a washer, the catalogue choice when size, speed or interrupted lubrication rules out sheet steel. Envelope 150×250×80 mm (5.906×9.843×3.15 in), 50.0 mm radial section, C 390 kN, C0 1290 kN, Pu 34 kN. reference speed 900 r/min (thermal) and limiting speed 1,300 r/min (mechanical), catalogue mass 16500 g. Capacity density: 390 kN C from 16.500 kg of bearing steel gives about 23.6 kN per kilogram; static density is correspondingly 78.2 kN/kg at C0 1290 kN. Pitch-diameter arithmetic: dm = (150+250)/2 = 200.0 mm; at the 1,300 r/min limiting speed that corresponds to roughly 260k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Static-first selection data: 1290 kN C0 spread across the 80 mm stack gives 16.1 kN of static rating per height millimetre, and the 16500 g mass/C0 ratio is about 13 g per static kN — crane-hook and screw positions are normally sized on these two figures. Sizing arithmetic on the 150 mm bore: 390 kN C over the 50.0 mm radial section gives 7.8 kN per section millimetre, and the 80 mm stack height is 1.60× that section — proportions typical of a 51300 thrust section. Track-circle loading: per millimetre of mean track circumference the 390 kN dynamic rating corresponds to roughly 0.62 kN/mm of π·dm track, a useful comparison against the other dimension series of the 150 mm bore. Machined-cage order-number note: the M brass cage is a one-piece ball-centred window cage, chosen at the heavy end of the section for speed and shock duty; it is heavier and stiffer than the pressed-steel execution of the smaller sizes and tolerates interrupted lubrication far better, which is why the catalogue restricts the M suffix to the large bores. The M cage of 51330 M adds a small amount of mass and cage strength without changing the 150×250×80 mm ISO 104 envelope, so the pressed-cage execution drops into the same recess but should not be assumed equal under the 1,300 r/min ceiling.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 150 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• The three components are separable and interchangeable within the ISO 104 size, but keep this bearing's parts together in service and never combine washers from different manufacturers or a worn washer with a new ball set.
• The third digit grades the section: 511 light, then 512, 513 and 514 progressively taller and heavier at the same bore — select from 390/1290 kN and the available 250 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• When the housing seat cannot be machined square to the 150 mm shaft, the sphered 53-series execution of this size with its U seat washer is the self-aligning counterpart of this flat 51300 bearing.
• The 390/1290 kN figures belong to 51330 M specifically (the single flat brass execution of 51330); suffixed, sphered and counterpart-series order numbers are separate articles, so write the complete designation on the order and the maintenance record.