51310-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 51310-SKF model number is decoded

51310 is SKF's 50 mm-bore single-direction thrust ball bearing in the 51300 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 50×95×31 mm. The separable set comprises a shaft washer (ground bore, tight fit on the shaft), a loose-bore housing washer and one ball-cage assembly, reacting axial force in one direction and carrying no radial load. in the 51xxx designation the first 1 marks a single-direction bearing with a flat housing seating surface; the third digit 1–4 grades the dimension series from the light 511 section through the heavy 514 section. the final two digits 10 encode the bore as 50 mm (code 10 × 5), the standard SKF bore-code rule shared with radial bearings. with no cage suffix this is the standard execution with a stamped sheet-steel ball-cage assembly (pressed cage) — the light, quiet and economical cage for small and medium thrust-ball sizes. Envelope 50×95×31 mm (1.969×3.74×1.22 in), 22.5 mm radial section, C 81.9 kN, C0 170 kN, Pu 6.3 kN. reference speed 2,600 r/min (thermal) and limiting speed 3,600 r/min (mechanical), catalogue mass 940 g. Stack/annulus proportions: the 31 mm axial stack over the 5,125 mm² washer annulus gives 6.05 mm of height per annular square millimetre ×10⁻³, and at 940 g the bearing holds about 180.9 kN of C0 per kilogram. Selection figures for 51310: the C0/C ratio is 2.08, Pu 6.3 kN is about 8 % of C, and the catalogue mass works out to roughly 19 g per millimetre of bore; the printed minimum-load factor is A 0.19. Speed band width for this size is 1,000 r/min between reference and limiting (1.38× ratio); lubrication, preload and heat removal decide where inside that band 51310 can actually run. Speed planning separates the two ceilings mechanically: the pressed cage and balls tolerate 3,600 r/min while thermal balance under catalogue load sets the 2,600 r/min reference; at dm ≈ 72.5 mm the corresponding dn is approximately 261k mm·r/min. Capacity density: 81.9 kN C from 0.940 kg of bearing steel gives about 87.1 kN per kilogram; static density is correspondingly 180.9 kN/kg at C0 170 kN. 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 50 mm size the pressed cage and separable washers make the bearing interchangeable across brands on the ISO 104 plan, but the SKF ratings 81.9/170 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 81.9/170 kN and the available 95 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• 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 81.9 kN track before first rotation.
• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 0.19; for 51310 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.
• 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 51310 against two-way load lifts the loose washer off its raceway.
• Ordering discipline for 51310: the catalogue page quotes 51310 and its 81.9/170 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.