51338-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 51338-M model number is decoded

The 51300 series order number 51338 M is a SKF single-direction thrust ball bearing for a 190 mm seat, built to ISO 104, with a flat housing seating surface, 190×320×105 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 38 decodes to 190 mm (code 38 × 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 190×320×105 mm (7.48×12.598×4.134 in), 65.0 mm radial section, C 559 kN, C0 2200 kN, Pu 51 kN. reference speed 700 r/min (thermal) and limiting speed 950 r/min (mechanical), catalogue mass 36500 g. Track-circle loading: per millimetre of mean track circumference the 559 kN dynamic rating corresponds to roughly 0.70 kN/mm of π·dm track, a useful comparison against the other dimension series of the 190 mm bore. Light-load floor: Pu = 51 kN is the equivalent-load threshold below which the SKF adjusted-life equation credits very long life for 51338 M; the number is 9 % of the 559 kN dynamic rating. Stack/annulus proportions: the 105 mm axial stack over the 52,072 mm² washer annulus gives 2.02 mm of height per annular square millimetre ×10⁻³, and at 36500 g the bearing holds about 60.3 kN of C0 per kilogram. Mass and section check: 36500 g inside the 190×320×105 mm outline leaves a 65.0 mm radial section, and the 2200 kN static rating is 3.94× the dynamic rating — plan static safety and minimum preload against those figures. Capacity density: 559 kN C from 36.500 kg of bearing steel gives about 15.3 kN per kilogram; static density is correspondingly 60.3 kN/kg at C0 2200 kN. 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. At 36500 g the machined brass cage represents a meaningful fraction of total mass; balancing checks on high-speed 190 mm vertical shafts should use the actual M-execution weight, not the lighter pressed-cage catalogue value.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 30; for 51338 M a spring preload or the rotor weight is part of the selection at light load and high speed, because unloaded balls skid rather than roll.
• The 51338 M is a pure axial bearing: it must never be subjected to radial load — any radial force on the 190 mm shaft has to be carried by a radial bearing mounted alongside it.
• The third digit grades the section: 511 light, then 512, 513 and 514 progressively taller and heavier at the same bore — select from 559/2200 kN and the available 320 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 190 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• Ordering discipline for 51338: the catalogue page quotes 51338 M and its 559/2200 kN ratings as one exact article; bare-number substitutions from another series or brand need a fresh dimension and rating check, not a like-for-like assumption.