RHP7006CTDUHP4Super-Precision Angular Contact Ball Bearing 30 x 55 x 13 mm, 15 Degree Contact Angle, P4 ABEC 7, Phenolic Cage, Heavy Preload Duplex Half, Open, 1 Pc

Product Description

What this part is

One RHP super-precision angular contact ball bearing in the 7006 envelope — 30 mm bore, 55 mm outside diameter, 13 mm width. Open, 15° contact angle, phenolic cage, P4 tolerance class, ground as one half of a heavy-preload duplex set. Built for machine-tool spindles, grinding heads and precision high-speed rotary work.

Decoding the designation

7006 — ISO 70-series angular contact size, 30 x 55 x 13 mm.
C — 15° contact angle in RHP nomenclature.
T — phenolic cage.
DU — duplex, universally ground.
H — heavy preload.
P4 — ABEC 7 tolerance class.
-1/2PR — half of a pair. This is the piece count, and it means one bearing.

What these specs mean in practice

Heavy preload buys spindle rigidity: minimum axial and radial deflection under cutting load, tight tool position, good surface finish. The bill is friction, heat and a lower usable speed than the same bearing at light or medium preload, so heavy preload belongs on stiff, moderate-speed spindles rather than the highest-rpm ones. The 15° contact angle pulls the other way — it keeps ball loading closer to radial, which limits heat and favours speed, at the cost of thrust capacity against a 25° build in the same envelope. P4 holds bore, outside diameter and running accuracy to ABEC 7 limits, so runout is tight enough that the shaft and housing seats have to be ground to match or the class is wasted. The phenolic cage is light, quiet and self-lubricating, but it will not tolerate aggressive solvents or sustained high temperature.

Quantity and configuration

1 Pc. The -1/2PR suffix means half of a pair, so one bearing ships, not two. The ring is ground as part of a heavy-preload duplex set, which means clamping it against a second bearing carrying the same DUH code produces the specified heavy preload with nothing to shim. On its own it works perfectly well as a single angular contact bearing against an opposing bearing or spring pack.

Fitting notes

Angular contact bearings take thrust one way only, so the assembly must oppose it. If you are building a preloaded pair, the mating bearing must be the same DUH code from the same scheme — mixing preload grades or manufacturers throws the ground stand-off away. Heavy preload leaves very little margin for a tight interference fit, because the fit adds preload on top of what is already ground in; check shaft and housing sizes against the spindle drawing first. Seats must be clean, burr-free and ground. Lubricate sparingly with a spindle grease or run oil-air, and never press through the balls.

Interchange guidance

RHP bearing production passed to NSK, and RHP super-precision numbers map onto NSK’s metric scheme, so B7006X2 designations describe the same envelope. Genuine 15° cross-references in this size include SKF 7006 CD/P4A, FAG B7006-C-T-P4S, NSK 7006C and Fafnir/Timken 2MM9106WI. Related sizes share the identical 30 x 55 x 13 mm envelope with a different contact angle — 7006E or 7006AC is the 25° build, a different part rather than a substitute. Preload grade is not interchangeable either: DUL (light) and DUM (medium) are also available in this size and change both stiffness and speed capability.