51405-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 51405-SKF model number is decoded

The 51400 series order number 51405 is a SKF single-direction thrust ball bearing for a 25 mm seat, built to ISO 104, with a flat housing seating surface, 25×60×24 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 05 decodes to 25 mm (code 05 × 5) under the same 00/01/02/03-exception, ×5 rule SKF uses across its coded bearing ranges. the suffix-free listing carries the catalogue default: a pressed (stamped sheet-steel) ball-cage assembly, light and quiet, used across the small and medium sizes. Envelope 25×60×24 mm (0.984×2.362×0.945 in), 17.5 mm radial section, C 42.3 kN, C0 67 kN, Pu 2.45 kN. reference speed 3,600 r/min (thermal) and limiting speed 5,000 r/min (mechanical), catalogue mass 340 g. Static-first selection data: 67 kN C0 spread across the 24 mm stack gives 2.8 kN of static rating per height millimetre, and the 340 g mass/C0 ratio is about 5 g per static kN — crane-hook and screw positions are normally sized on these two figures. At the printed limiting speed of 5,000 r/min the mean pitch diameter dm ≈ 42.5 mm implies a dn value around 213k mm·r/min; the 3,600 r/min reference speed is the thermal-planning value under catalogue load. Selection figures for 51405: the C0/C ratio is 1.58, Pu 2.45 kN is about 6 % of C, and the catalogue mass works out to roughly 14 g per millimetre of bore; the printed minimum-load factor is A 0.048. Mass and section check: 340 g inside the 25×60×24 mm outline leaves a 17.5 mm radial section, and the 67 kN static rating is 1.58× the dynamic rating — plan static safety and minimum preload against those figures. Speed-ratio note for this exact unit: the reference speed is 3,600 r/min against a 5,000 r/min limiting speed, a reference-to-limit ratio of 0.72. 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 25 mm size the pressed cage and separable washers make the bearing interchangeable across brands on the ISO 104 plan, but the SKF ratings 42.3/67 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

• Heat the shaft washer to at most 120 °C for mounting, or press it via a sleeve on its ground bore — force applied through the housing washer or the ball set brinells the 42.3 kN track before first rotation.
• 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 51405 against two-way load lifts the loose washer off its raceway.
• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 0.048; for 51405 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 51405 is a pure axial bearing: it must never be subjected to radial load — any radial force on the 25 mm shaft has to be carried by a radial bearing mounted alongside it.
• The 42.3/67 kN figures belong to 51405 specifically (the single flat pressed steel execution of 51405); suffixed, sphered and counterpart-series order numbers are separate articles, so write the complete designation on the order and the maintenance record.