RHP7218CTDUMP4Angular Contact Ball Bearing Matched Pair – Straight Bore, 90 mm ID, 160 mm OD, 30 mm Width, Open, 15° Contact Angle, Medium Preload

Product Description

What this part is

RHP 7218CTDUMP4 super precision angular contact ball bearings, supplied as a matched duplex pair. Series: 7200, ISO dimension series 02. Bore: 90 mm. Outside diameter: 160 mm. Width: 30 mm each bearing, 60 mm assembled. Straight bore, open on both faces, ball rolling elements in chrome bearing steel to SAE 52100. Country of origin as recorded: United Kingdom.

Decoding the designation

Contact Angle: 15°. Cage: laminated phenolic resin, machined and outer-ring guided. Grouping: DU, paired unit. Preload: M, medium. Precision Grade: P4, equal to RHP EP7 and ABEC 7. Searchable forms include 7218CTDUMP4, 7218-C-T-DUM-P4, 7218 C T DUM P4, 7218C, the RHP B-series form B7218X2TADUMEP7 and the Fafnir crosses 2MM218WICR-DUM and 218HDM.

What these specs mean in practice

Dynamic Load Rating: 123 kN per bearing. Static Load Rating: 105 kN per bearing. Limiting speed for a single bearing: 7,800 rpm with grease, 13,400 rpm with oil/air. Medium preload carries a 0.60 factor on a back-to-back pair, giving 4,680 rpm and 8,040 rpm. Medium preload sits between light and heavy, reaching 187 N/µm of axial stiffness at 1,860 N of preload, which suits a spindle that needs more rigidity than a light setting gives without the heat penalty of a heavy one. A 15° contact angle runs faster and carries less thrust than a 25° bearing on the same envelope.

Quantity and configuration

Two bearings, a matched duplex pair. Universal face control means they mount back-to-back, face-to-face or in tandem at the same medium preload, set at manufacture.

Fitting notes

Abutment diameters from the RHP super precision tables: shaft shoulder d1 minimum 100 mm, housing shoulder D1 maximum 150 mm, D2 maximum 154 mm. Fillet radius r minimum 2.5 mm, r1 minimum 1.0 mm. Effective load centre a = 31.7 mm. Internal free volume 95.1 cm³ per bearing. Lubrication jet pitch circle 116.7 mm. Mass 2.206 kg per bearing, 4.412 kg for the pair.

Interchange guidance

Same-specification equivalents at 15° and medium preload: SKF 7218 CD/P4ADGB, FAG B7218-C-T-P4S-DUM, Fafnir 2MM218WICR-DUM, NSK 7218CTRDUMP4. RHP 7218ETDUMP4 is a related size at 25°.