SKF 51210 Single Direction Thrust Ball Bearing, 50x78x22 mm

A single direction thrust ball bearing for pure axial load on a 50 mm shaft

The SKF 51210 is a single direction thrust ball bearing with a 50 mm shaft washer bore, 78 mm outside diameter and 22 mm height. It consists of a shaft washer with a raceway groove, a ball and cage assembly and a housing washer, all separable. It can only carry axial load in one direction and must not be subjected to any radial load, so it is paired with a separate radial bearing or located by a guided shaft. The separable washers make mounting and inspection easy, and many components are interchangeable; the shaft washer has a ground bore for an interference fit.

Typical uses are vertical pump and gearbox shafts, crane hook blocks, screw jacks, turntables and swivels where the axial load always acts the same way. Where the shaft load reverses, SKF makes double direction thrust bearings, and where the thrust is heavy and misalignment is likely it makes spherical roller thrust bearings, so this ball bearing is the light, economical choice for pure thrust.

Technical specifications

Neighbouring sizes in the 512 series

The rows are the 51200 series sizes around the 51210 from the SKF catalogue table, which lists the speed ratings and mass; the larger catalogue range runs from 10 to 140 mm bore.

Selection and mounting notes

A thrust ball bearing needs a minimum axial load to keep the balls rolling correctly, particularly at speed; the catalogue gives a minimum load factor of 69 for the 51210. At high speed the centrifugal force on the balls tends to push them outward, so a thrust ball bearing is not a high speed bearing; the limiting speed listed is 4,500 r/min, and the reference speed is 3,400 r/min. The flat housing washer needs a well machined, perpendicular housing face. If the housing cannot be machined that accurately, SKF offers sphered housing washers used with seating washers to compensate for initial misalignment.

Fit the shaft washer with an interference fit on the ground bore, and keep the housing washer with clearance in its bore so that it can centre on the balls. Lubricate with grease or oil and avoid contamination, since thrust bearings are sensitive to dirt. Before ordering, check whether you need the single direction 511 series (this page) or the double direction 522 series, and confirm the radial support is provided elsewhere. Radial ball bearings such as the SKF 6206-2RS1 are on this site, and all bearings are grouped under Ball Bearings.

Related SKF products: SKF 7312 BECBM Angular Contact Ball Bearing, 60 mm, SKF 6314 Deep Groove Ball Bearing, 70x150x35 mm, SKF 6205-2RSH/C3 Sealed Deep Groove Ball Bearing, SKF 6316 M/C3VL0241 INSOCOAT Insulated Ball Bearing, SKF 6212-2Z/VA228 High Temperature Ball Bearing and SKF 6206-2RS1 Deep Groove Ball Bearing.

Documents and ordering

The attached PDF is a two-page extract from the SKF catalogue SKF bearings and mounted products (SKF USA edition): the thrust bearing introduction covering single and double direction thrust ball bearings, and the 51200 to 51228 product table. Send the designation 51210, the quantity and the application so that Seven Star LLC can quote. Seven Star LLC is an independent supplier in Muscat; availability and lead time are confirmed per enquiry.