RHP7209CTDUMP4Super-Precision Angular Contact Ball Bearing Matched Pair 45 x 85 x 19 mm, 15° Contact Angle, Medium Preload, ABEC 7

Product Description

What this part is

A matched duplex pair of super-precision angular contact ball bearings, 45 mm bore, 85 mm outside diameter, 19 mm width per bearing, with a 15° contact angle, phenolic cage, medium preload and P4 running accuracy.

Decoding the designation

7209 — angular contact ball bearing, 72 series, bore code 09 = 45 mmC — 15° contact angle in the RHP/NSK schemeT — phenolic (laminated fabric) cageDU — duplex, ground as a matched pairM — medium preloadP4 — ABEC 7 precision class

What these specs mean in practice

A 15° contact angle biases the bearing toward speed and radial stiffness; a 25° angle in the same envelope carries more thrust and runs slower. The duplex ground faces let the two rings be clamped face-to-face or back-to-back with the preload set by the manufacturer, so axial stiffness is repeatable without shimming.

Medium preload sits between light and heavy: more axial rigidity and tighter shaft position than light preload, with more heat generation and a lower speed ceiling.

A phenolic cage is light and self-lubricating, which suits high dn values and oil-mist or grease lubrication, with a service temperature ceiling below that of a metal cage.

P4 governs bore, outside diameter and raceway runout to ABEC 7 limits — the class used for machine tool spindles and precision ballscrew and worm drives.

Quantity and configuration

Two bearings, supplied as one matched duplex pair. Combined width across the pair is 38 mm. Open both faces, no seals or shields.

Fitting notes

Duplex ground rings are mounted in the orientation marked on the ring faces, with the marks aligned so the ground offset produces the intended preload. Clamping is done against square, ground abutment faces, and the pair is handled as a set.

Interchange guidance

Same-spec equivalents to this pair: Fafnir 2MM209WI CR DUM, NSK 7209CTRDUMP4, FAG B7209-C-T-P4S-DUM, SKF 7209 CD/P4ADGB. A 7209E pair has a 25° contact angle and a 7209CTDUL or 7209CTDUH pair has light or heavy preload; both share the 45 × 85 × 19 mm envelope and are related sizes.