RHP7005ETDULP4Super Precision Angular Contact Ball Bearing Matched Pair 25x47x12 mm 25° ABEC 7 Light Preload

Product Description

What this part is

A duplex-ground matched pair of single-row super-precision angular contact ball bearings. Each bearing is 25 mm bore, 47 mm outside diameter, 12 mm width, ground to a 25° contact angle and a light preload band. The pair clamps as one unit at 24 mm total width.

Decoding the designation

The 70 prefix and bore code 05 give ISO dimension series 70 at a 25 mm bore. In the RHP scheme E is a 25° contact angle, T a machined phenolic laminate cage, DU duplex universal grinding, L the light preload grade, and P4 super-precision tolerances to ABEC 7 / ISO class 4. The carton also carries 7005ACD, whose AC element is 25° in the SKF scheme, confirming the angle from a second designation.

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 increases ball centrifugal and gyroscopic effects, giving a lower limiting speed and more heat at equal duty.

Light preload trades stiffness for heat. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable, and the friction it creates goes into the rings as heat that shifts the preload as the spindle warms. The L grade adds the least of it, which is why light-preload duplex sets go into fast, moderately loaded spindles and grinding heads while M and H grades go into stiffer, slower stacks.

P4 holds bore, outside diameter, width and running accuracy to single-digit micron limits. Duplex grinding is what converts those tolerances into a preload: the ring faces are relieved by a measured amount, so clamping the pair solid produces the light preload directly with no shimming.

Quantity and configuration

Matched pair, 2 Pcs, duplex ground as one set.

Fitting notes

The pair is assembled in the orientation its face marks indicate, most often back-to-back for moment stiffness, and the inner rings are clamped solid against one another so the ground relief sets the preload. A duplex set behaves as a single bearing, and its preload band of a few microns belongs to that specific pair. Shaft and housing seats at this class are ground and measured, typically j4 to k4 on the shaft and H5 to J5 in the housing.

Interchange guidance

7005E is the RHP designation for the 25° version of this envelope, and 7005ACD is the SKF-scheme form of the same angle. Same-envelope bearings differing in contact angle, preload grade or tolerance class — 7005C at 15°, the medium and heavy preload sets, and P0 or P5 class variants — are related sizes rather than interchanges. A single universally ground bearing of this size is a different item, since SU pieces are not ground to this pair’s stack height.