NSKSuper Precision Angular Contact Ball Bearing Pair 25x47x12 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 25 mm bore × 47 mm outside diameter × 12 mm width envelope, the ISO 7005 size. Single row each, universally ground so the pair reaches its specified preload when clamped solid.

Decoding the designation

This record carries two designations and they agree with each other. In the NSK string 7005A5TYDULP4 the A5 is a 25° contact angle, distinct from A at 30° and C at 15°. DUL is duplex universal with light preload and P4 is the class equivalent to ABEC 7. The alternate number 7005E is the RHP form of the same bearing, in which E independently gives the 25° angle.

What these specs mean in practice

A 25° contact angle is the thrust-biased choice in this envelope. Axial capacity and axial stiffness both rise with contact angle, so a 25° pair holds a spindle’s axial position harder under cutting thrust than the 15° version of the same size. The cost is speed: the steeper load line raises ball centrifugal and gyroscopic effects, which lowers the limiting speed and adds heat at equal duty. Light preload adds the least of that heat, which is why it suits fast, moderately loaded spindles and grinding heads.

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. Seats at this class are ground and measured, and the preload is only realised when both outer rings seat fully in the housing bore.

Interchange guidance

The same-spec equivalents are RHP 7005ETDULP4 and Timken 3MM9105WI CR DUL, the Fafnir-scheme 3MM prefix likewise denoting 25°. Bearings sharing the 25 × 47 × 12 mm envelope with a different contact angle, preload grade or class, such as the 7005C at 15° or a medium-preload set, are related sizes rather than substitutions. A single universally ground bearing of this size is a different item, since it is not ground to this pair’s stack height.