51184-F 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 51184-F model number is decoded

The 51100 series order number 51184 F is a SKF single-direction thrust ball bearing for a 420 mm seat, built to ISO 104, with a flat housing seating surface, 420×500×65 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 84 decodes to 420 mm (code 84 × 5) under the same 00/01/02/03-exception, ×5 rule SKF uses across its coded bearing ranges. the F suffix denotes a steel cage machined from solid and centred on the balls, reserved for the largest OD sizes whose ball mass is beyond pressed-cage guidance. Envelope 420×500×65 mm (16.535×19.685×2.559 in), 40.0 mm radial section, C 410 kN, C0 2400 kN, Pu 41.5 kN. reference speed 700 r/min (thermal) and limiting speed 1,000 r/min (mechanical), catalogue mass 25500 g. Speed band width for this size is 300 r/min between reference and limiting (1.43× ratio); lubrication, preload and heat removal decide where inside that band 51184 F can actually run. Rating split for documentation: dynamic 410 kN (L10 life), static 2400 kN (safety factor s0), fatigue limit 41.5 kN (adjusted life) — three different uses of three different numbers for 51184 F, none interchangeable with another. At the printed limiting speed of 1,000 r/min the mean pitch diameter dm ≈ 460.0 mm implies a dn value around 460k mm·r/min; the 700 r/min reference speed is the thermal-planning value under catalogue load. Mass and section check: 25500 g inside the 420×500×65 mm outline leaves a 40.0 mm radial section, and the 2400 kN static rating is 5.85× the dynamic rating — plan static safety and minimum preload against those figures. Bore-to-OD planning: OD 500 over bore 420 is a 1.19× step for this size, and the 65 mm height gives a bore/height ratio of 6.46; use these ratios when the housing recess around the 420 mm shaft is the first constraint. Large-size execution note: the F machined steel cage exists because the ball complement and pitch diameter of the biggest 512-series sizes are beyond pressed-cage guidance; the steel cage is machined from solid, ball-centred, and its heavier mass must be supported by genuine oil or grease flow at start-up — never mount an F bearing dry for a trial rotation. The F execution appears only at the 420 mm top end of the range: the 500 mm OD ball complement is large enough that cage centrifugal forces dictate a machined guide, which is also why the 2400 kN C0 figure dominates selection of this order number.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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 51184 against two-way load lifts the loose washer off its raceway.
• When the housing seat cannot be machined square to the 420 mm shaft, the sphered 53-series execution of this size with its U seat washer is the self-aligning counterpart of this flat 51100 bearing.
• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 30; for 51184 F 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.
• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 420 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 51184 F as the single flat machined steel execution; other order numbers of the 51184 size are different products and may carry different ratings or seating geometry — always quote the full designation when purchasing.