SKF 1310 ETN9 Self-Aligning Ball Bearing, 50x110x27 mm

A 50 mm bore self-aligning ball bearing for shafts that flex or mount out of line

The SKF 1310 ETN9 is a double row self-aligning ball bearing with a 50 mm bore, 110 mm outside diameter and 27 mm width. Its two rows of balls run on a common sphered raceway in the outer ring, so the inner ring and shaft can tilt relative to the housing without the bearing binding. That makes it the standard answer where two housings cannot be aligned exactly, where a long shaft deflects under load, or where a fabricated frame distorts. SKF notes that a non-sealed self-aligning ball bearing has the lowest friction of any bearing type, which is why the design is common on fans, line shafts, conveyors, agricultural machinery and textile and woodworking equipment.

The E in the designation marks the internal design with higher load ratings than the original standard design, and TN9 is the non-metallic cage that SKF fits as standard on these sizes. The bearing is open, so it is normally lubricated from the housing. It is a light to moderate load bearing: the static rating of 14 kN is modest against its dynamic rating of 43.6 kN, and it is not intended for heavy axial or shock loads.

Technical specifications

Size table for the 13 series, cylindrical bore

The rows below are the neighbouring sizes of the same E series from the SKF catalogue table, so you can compare the 1310 E with the next size up or down. Values are for the open bearing with cylindrical bore; mass is approximate.

Selection, clearance and mounting notes

Self-aligning ball bearings are supplied with Normal radial internal clearance (CN) as standard; for the 40 to 50 mm bore range the catalogue gives a Normal clearance of 14 to 31 micrometres, with C3 at 25 to 44 micrometres for applications with a tight shaft fit or a warm inner ring. The bearing carries combined loads; the catalogue gives the equivalent dynamic load as P = Fr + Y1 Fa when Fa/Fr is not above e, and P = 0.65 Fr + Y2 Fa above it, using e = 0.24, Y1 = 2.6 and Y2 = 4.1 for the 1310 E.

On the shaft the 1310 ETN9 is a plain cylindrical-bore bearing, so it needs a shoulder and a locking nut or retaining arrangement of your own. If you want to mount it on a smooth shaft with an adapter sleeve, the catalogue lists the tapered-bore equivalent 1310 EK with H 310 sleeve; these tapered-bore bearings are normally supplied with C3 clearance and are fitted by measuring clearance reduction or axial drive-up as described in the SKF installation guide. Check also that the loads are high enough: like other bearings, self-aligning ball bearings need a minimum radial load, especially at high speed, which often comes from the weight of the shaft or belt tension.

Comparable sealed bearings are listed on this site, for example the SKF 6206-2RS1 for compact electric motors, and the full range is grouped under Ball Bearings.

Related SKF products: SKF 6314 Deep Groove Ball Bearing, 70x150x35 mm, SKF 7312 BECBM Angular Contact Ball Bearing, 60 mm, SKF 6206-2RS1 Deep Groove Ball Bearing, SKF 6205-2RSH/C3 Sealed Deep Groove Ball Bearing, SKF 6316 M/C3VL0241 INSOCOAT Insulated Ball Bearing and SKF 6208/HC5C3 Hybrid Ceramic Deep Groove Ball Bearing.

Documents and ordering

The attached PDF is a three-page extract from the SKF catalogue SKF bearings and mounted products (SKF USA edition): the self-aligning ball bearing introduction with radial clearance and load formulas, and the 13 series product table. Before ordering, confirm the full designation (1310 ETN9 or 1310 EKTN9), clearance class, shaft and housing fits, the lubricant and whether sealed or shielded variants would suit better. Seven Star LLC is an independent supplier in Muscat; availability and lead time are confirmed per enquiry.