RHP7203ETDULP4VSuper Precision Angular Contact Ball Bearing Pair 17x40x12 mm, 25° Contact Angle, Light Preload, ABEC 7

Product Description

What this part is

A matched pair of super-precision angular contact ball bearings in the 17 mm bore × 40 mm outside diameter × 12 mm width envelope, the ISO 7203 size. Single row each, machined cage, universally ground so the pair reaches its specified preload when clamped solid.

Decoding the designation

In the RHP scheme the 7203 gives the ISO size, E is a 25° contact angle, T the machined phenolic cage, DUL duplex universal with light preload, and P4 the class equivalent to ABEC 7. The second designation on this record, 7203E, independently confirms the 25° angle.

What these specs mean in practice

A 25° contact angle is the thrust-biased middle choice in the super-precision range. Axial capacity and axial stiffness both rise with the angle, so a 25° pair holds a spindle’s axial position harder under cutting thrust than the 15° version of the same size, at the cost of limiting speed and added heat at equal duty. Light preload adds the least of that heat, which suits fast, moderately loaded spindles and grinding heads. The phenolic cage is light, holds an oil film well, and sets the temperature ceiling at roughly 120 °C, which governs ahead of the steel.

Thrust direction

Each bearing carries radial load together with thrust in one direction only. Mounted back-to-back or face-to-face the pair locates the shaft axially in both directions, one row acting in each; mounted in tandem both act in the same direction at roughly doubled capacity.

Quantity and configuration

2 Pcs. One universally ground pair, 24 mm total width when clamped solid, supplied without spacers, locknut or housing.

Fitting notes

Universal grinding means the two rings stack back-to-back, face-to-face or in tandem and arrive at the specified light preload with no shimming or hand grinding. The pair is assembled in the orientation its face marks indicate and the inner rings are clamped solid against one another so the ground relief sets the preload. The preload is only realised when both outer rings seat fully in the housing bore.

Interchange guidance

RHP super-precision designations cross-reference directly to NSK, which acquired RHP and continued the numbering. The same-spec equivalents are NSK 7203A5TDULP4, where A5 is the NSK code for 25°, and Timken 3MM203WI CR DUL, whose 3MM prefix likewise denotes 25°. A 7203C at 15° shares this exact 17 × 40 × 12 mm envelope but is a related size rather than a substitution, as is a tandem-matched set or any medium or heavy preload version.