SKFN208MP5Single-Row Cylindrical Roller Bearing, 40 x 80 x 18 mm, Non-Locating N Design, Brass Cage, P5

Product Description

What this part is

An SKF N 208 M/P5 single-row cylindrical roller bearing, 40 mm bore, 80 mm outside diameter, 18 mm width. Cylindrical rollers make line contact with the raceways rather than the point contact of a ball, so this type carries substantially more radial load than a deep groove ball bearing of the same envelope while running at high speed.

Decoding the designation

The N design prefix is the non-locating cylindrical roller arrangement: the outer ring has no integral ribs and the inner ring has two, so the roller set can float axially against the outer raceway. Series 2 and bore code 08 give 40 mm bore in the 80 x 18 mm envelope. M is a machined solid brass cage, and /P5 is ISO tolerance class 5, equivalent to ABEC 5, tightening both dimensional tolerance and running accuracy over standard class. C781 is not part of the published SKF suffix scheme and is carried here as a searchable reference only.

What these specs mean in practice

A non-locating N-design bearing takes pure radial load and allows the shaft to expand or contract axially inside the bearing itself, which is what makes it the free end of a two-bearing shaft where the other end is axially fixed. Substituting an axially locating design in the same envelope removes that freedom and loads the ribs thermally. A machined brass cage is stiffer and more tolerant of high speed, shock and marginal lubrication than a pressed or polyamide cage and carries no polymer temperature ceiling. P5 class narrows radial and axial runout, so the bearing suits machine-tool and spindle positions where shaft run-out is a specification rather than a consequence.

Quantity and configuration

1 Pc. Straight bore, open both faces, no snap ring groove.

Fitting notes

The inner and outer rings of an N-design cylindrical roller bearing separate, so each ring is mounted to its own seat independently and the roller set enters the outer raceway as the shaft goes home. Mounting force passes through the ring being fitted alone. On a P5 bearing the shaft and housing seats are ground and measured to matching tolerance, since the class buys nothing if the seats are loose or out of round.

Interchange guidance

The genuine same-spec interchanges are other makers’ N 208 in class 5 with a machined brass cage: FAG N208-E-M1-P5, NSK N208MP5 and NTN N208MP5, all 40 x 80 x 18 mm and non-locating. NU 208, NJ 208 and NUP 208 share the 40 x 80 x 18 mm envelope but locate the shaft axially in one or both directions, so they are related sizes and not substitutions.