51307-SKF 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 51307-SKF model number is decoded

Listed in SKF 17000 chapter 5, 51307 is an ISO 104 single-direction thrust ball bearing, 35 mm bore and 68 mm OD on a flat housing seat, standing 24 mm high before installation. The bearing is delivered as separate, interchangeable parts: a ground-bore shaft washer, a loose-bore housing washer and the ball-cage assembly between them, designed for one axial load direction only. 51xxx breaks down as 5 for thrust ball, 1 for one load direction on a flat seat, a section digit 1–4 light-to-heavy, then the two-digit bore code. reading the ending 07: bore 35 mm (code 07 × 5) for this single-direction size, via the standard exceptions 00/01/02/03 and ×5 above them. no cage suffix means the standard stamped steel retainer — a pressed sheet-metal ball-cage assembly that covers the bulk of the thrust-ball assortment. Envelope 35×68×24 mm (1.378×2.677×0.945 in), 16.5 mm radial section, C 49.4 kN, C0 96.5 kN, Pu 3.55 kN. reference speed 3,400 r/min (thermal) and limiting speed 4,800 r/min (mechanical), catalogue mass 390 g. Pitch-diameter arithmetic: dm = (35+68)/2 = 51.5 mm; at the 4,800 r/min limiting speed that corresponds to roughly 247k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Preload at the mechanical ceiling: repeating Fam ≈ A·(n·dm/1000)² with factor A 0.048 at the 4,800 r/min limiting speed raises the required axial preload to about 2.9 kN; the reference-speed value 1.5 kN is the thermal design point. At the printed limiting speed of 4,800 r/min the mean pitch diameter dm ≈ 51.5 mm implies a dn value around 247k mm·r/min; the 3,400 r/min reference speed is the thermal-planning value under catalogue load. Rating split for documentation: dynamic 49.4 kN (L10 life), static 96.5 kN (safety factor s0), fatigue limit 3.55 kN (adjusted life) — three different uses of three different numbers for 51307, none interchangeable with another. Stack/annulus proportions: the 24 mm axial stack over the 2,670 mm² washer annulus gives 8.99 mm of height per annular square millimetre ×10⁻³, and at 390 g the bearing holds about 247.4 kN of C0 per kilogram. Execution note for this order number: the flat housing seating surface must be machined square to the shaft axis and supported across the full washer face — unlike the sphered 53-series execution this pressed-cage 51-series bearing has no self-aligning capability at all, so seat squareness is checked at mounting, not compensated in service. On this 35 mm size the pressed cage and separable washers make the bearing interchangeable across brands on the ISO 104 plan, but the SKF ratings 49.4/96.5 kN are this catalogue's figures — confirm the replacement order's ratings rather than swapping on envelope alone.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• The third digit grades the section: 511 light, then 512, 513 and 514 progressively taller and heavier at the same bore — select from 49.4/96.5 kN and the available 68 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• On vertical shafts retain the loose housing washer positively with a cover or ring and verify the grease fill does not drain out of the 24 mm stack; thrust-ball bearings on horizontal shafts should have the shaft washer (the tight one) against the rotating element.
• The 51307 is a pure axial bearing: it must never be subjected to radial load — any radial force on the 35 mm shaft has to be carried by a radial bearing mounted alongside it.
• A 51-series bearing reacts thrust in one direction only — reversing positions need a mirrored single-direction pair or a 52-series double-direction unit; fitting a single 51307 against two-way load lifts the loose washer off its raceway.
• Ordering discipline for 51307: the catalogue page quotes 51307 and its 49.4/96.5 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.