RHP7006CTDULP4Super Precision Angular Contact Ball Bearing Pair – 30 mm ID, 55 mm OD, 13 mm Width, Open, 15 Degree, Light Preload, Phenolic Cage

Product Description

What this part is

An RHP super-precision angular contact ball bearing in the 7006 size, 30 mm bore by 55 mm outside diameter by 13 mm width, supplied as a universally ground matched pair for light-preload duplex mounting. RHP is the British line of NSK and the designation follows the shared RHP/NSK super-precision scheme.

Decoding the designation

7006 sets the boundary dimensions as the ISO 70 light series in the 30 mm bore size. C is the 15° contact angle. T is the phenolic cage, machined and outer-ring land riding. DUL is a duplex universal set at light preload — universally ground means either face can be brought together, so the same two rings will mount back-to-back, face-to-face or in tandem and reach the specified preload without shims. P4 is the precision class, equivalent to ABEC 7. The carton cross designation 2MM9106WICRDUL is the Timken/Fafnir WI-series equivalent of the same build, where 2MM confirms the 15° angle and CR confirms the phenolic outer-land-riding cage.

What these specs mean in practice

A 15° contact angle favours speed and radial capacity over thrust. Against a 25° bearing of the same envelope it runs faster and cooler and carries appreciably less axial load, which is why 15° is the usual machine-tool spindle choice at the tool end. Light preload is the lowest of the three standard grades, giving the least heat generation and the highest speed ceiling at the cost of some axial stiffness. The phenolic cage tolerates high cage speeds and is the reason for the 120 °C ceiling on this build.

Quantity and configuration

2 Pcs, one matched universal pair. Open bearings, no seals or shields fitted, no snap ring groove. Rings are ground for oil or grease lubrication with no relubrication feature built into the bearing itself.

Thrust direction

Each ring set is a single-row angular contact bearing and takes thrust in one direction only. Mounted back-to-back or face-to-face as a pair, the two rows between them locate the shaft in both directions; mounted in tandem, both rows share thrust in the same single direction.

Fitting notes

Universally ground rings are marked so the ground faces can be identified; bringing the marked faces together gives back-to-back with the specified light preload. Preload on a duplex pair is set by the ground offset, so clamping the rings axially against a spacer or shoulder is what develops it. Cleanliness and oil-film condition govern the achievable speed far more than the catalogue figure.

Interchange guidance

Direct equivalents at the same 15° angle, light preload and P4 class are SKF 7006 CD/P4ADLA, FAG B7006-C-T-P4S-DUL and NSK 7006CTYNDULP4, with the NSK carrying a polyamide rather than phenolic cage. A 7006 in a different angle letter, a different preload grade or a lower precision class is a related size rather than an interchange, since angle and preload both change the load and speed behaviour of the pair.