FAGB71808CTPAP4ULSuper-Precision Angular Contact Ball Bearing – Straight Bore, 40 mm ID, 52 mm OD, 7 mm Width, Open, 15° Contact Angle, Universal Light Preload.

Product Description

What this part is

FAG B71808C.TPA.P4.UL super-precision angular contact ball bearing, single row, open. Bore 40 mm, outside diameter 52 mm, width 7 mm. Fifteen-degree contact angle, ABEC 7 precision, phenolic laminate cage, universally ground for light preload.

Decoding the designation

B7 is the Schaeffler super-precision spindle bearing series. 18 gives the 718 dimension series, an extra-thin section for its bore; 08 is the bore code for 40 mm. C is the FAG 15° contact angle. TPA is the fabric-base laminate cage — textile laminated phenolic, ball-guided. P4 is the precision class, equivalent to ABEC 7. UL marks a universally ground bearing set for light preload.

What these specs mean in practice

The 15° angle is the high-speed, low-thrust end of the range: it favours running speed and radial stiffness over axial capacity, which is why it is the standard choice for machine tool spindles rather than for heavily thrust-loaded shafts. Limiting speed 24000 rpm. Load ratings are 5.4 kN dynamic and 5.3 kN static. The phenolic laminate cage is light and self-lubricating, suited to high speed with oil or light grease, with a working ceiling around 120 °C.

Preload and arrangement

Universal grinding means any two of these bearings mount together in back-to-back, face-to-face or tandem arrangement and reach the specified light preload without shims or spacers. Light preload gives the lowest running friction and heat generation of the preload classes, with correspondingly lower stiffness than medium or heavy.

Quantity and configuration

1 Pc. Single universally ground bearing, open on both faces, no snap ring.

Fitting notes

Contact angle direction is marked on the outer ring; arrangement is set by ring orientation on assembly. Mounting is by light interference on the shaft and a close fit in the housing, with the ring faces clamped square. Super-precision classes require clean handling and a controlled fit, as journal and bore geometry carry straight through to spindle runout.

Interchange guidance

SKF 71808 CD/P4 is the same envelope, 15° angle and precision class. Parts in this envelope with a 25° angle, or supplied as pre-matched duplex pairs, are related sizes rather than substitutions — the angle sets the load split and the pairing sets the sale unit.