51264-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 51264-M model number is decoded

51264 M is SKF's 320 mm-bore single-direction thrust ball bearing in the 51200 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 320×440×95 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 64 encode the bore as 320 mm (code 64 × 5), the standard SKF bore-code rule shared with radial bearings. suffix M identifies a one-piece machined brass cage, ball-centred: the large-size and heavy-section option for higher speeds, shock loads and thin-film lubrication where a pressed cage would distort. Envelope 320×440×95 mm (12.598×17.323×3.74 in), 60.0 mm radial section, C 572 kN, C0 3000 kN, Pu 56 kN. reference speed 600 r/min (thermal) and limiting speed 800 r/min (mechanical), catalogue mass 45000 g. Speed-ratio note for this exact unit: the reference speed is 600 r/min against a 800 r/min limiting speed, a reference-to-limit ratio of 0.75. Mass and section check: 45000 g inside the 320×440×95 mm outline leaves a 60.0 mm radial section, and the 3000 kN static rating is 5.24× the dynamic rating — plan static safety and minimum preload against those figures. Minimum-load arithmetic: with dm ≈ 380.0 mm and factor A 47, Fam ≈ A·(n·dm/1000)² at the 600 r/min reference speed is about 2443.2 kN for 51264 M; below that preload the balls skid and smear the tracks. Sizing arithmetic on the 320 mm bore: 572 kN C over the 60.0 mm radial section gives 9.5 kN per section millimetre, and the 95 mm stack height is 1.58× that section — proportions typical of a 51200 thrust section. Load balance: C0 3000 kN against C 572 kN gives a 5.24 ratio — thrust ball bearings are chosen on static rating and F_a/C0 far more often than on L10 life, while Pu 56 kN enters the adjusted-life check. 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 45000 g the machined brass cage represents a meaningful fraction of total mass; balancing checks on high-speed 320 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 47; for 51264 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.
• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 320 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• 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 51264 against two-way load lifts the loose washer off its raceway.
• The 51264 M is a pure axial bearing: it must never be subjected to radial load — any radial force on the 320 mm shaft has to be carried by a radial bearing mounted alongside it.
• Ordering discipline for 51264: the catalogue page quotes 51264 M and its 572/3000 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.