RHP7005CTDUMP4Super Precision Angular Contact Ball Bearing Matched Pair 25x47x12 mm 15° ABEC 7 Medium Preload

Product Description

What this part is:

A duplex-ground matched pair of RHP 7005C single-row super-precision angular contact ball bearings. Bore: 25 mm. Outside Diameter: 47 mm. Overall Width: 12 mm per bearing. Total Width: 24 mm for the clamped pair. Contact Angle: 15°. Precision Class: P4, ISO Class 4, ABEC 7, RHP class code EP7. Cage Material: laminated phenolic resin. Cage Type: machined, outer-ring guided. Closure Type: open on both faces. Bore Type: straight. Rolling Elements: carbon chrome bearing steel balls. Series: RHP 70, ISO dimension series 10. Number Of Rows: 1 per bearing. Bearing Material: carbon chrome bearing steel to BS970 534A99/535A99 or SAE 52100.

Decoding the designation:

Type 7: single-row angular contact ball bearing. Dimension series 0: ISO series 10. Bore code 05: 25 mm bore. Contact angle C: 15°. Cage T: laminated phenolic resin, outer ring guided. Grouping DU: matched duplex pair, universally face-controlled. Preload M: medium. Precision grade P4: ISO Class 4, ABEC 7, British Standard EP7.

Load ratings and speed:

Dynamic Load Rating (Cr): 11,700 N, 11.7 kN. Static Load Rating (C0r): 7,400 N, 7.4 kN. Limiting Speed, oil/air lubrication: 47,500 rev/min. Limiting Speed, grease lubrication: 29,300 rev/min. Those figures apply to a single bearing under a spring preload with the inner ring rotating. A back-to-back medium-preload pair takes a 0.60 speed factor, a set of three 0.50 and a set of four 0.45. A face-to-face arrangement takes a further 50 per cent reduction. A spring-loaded tandem pair takes 0.95. Lubricant: oil/air or grease. Maximum Operating Temperature: 120 °C, set by the laminated phenolic cage.

What these specs mean in practice:

A 15° contact angle is the speed-biased choice in this family. The shallow load line keeps ball centrifugal and gyroscopic effects low, so a 15° pair reaches a higher limiting speed and runs cooler than a 25° pair of the same envelope, giving up axial capacity and axial stiffness in exchange.

Medium preload sits between the light and heavy grades. Axial Preload, medium grade, as a paired set: 150 N. Axial Stiffness, medium grade, as a paired set: 48 N per micrometre. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable, and the friction it creates becomes heat in the rings. The M grade buys more axial and radial stiffness than L at the cost of more heat and a lower speed factor, which suits a spindle carrying real cutting load rather than one chasing maximum speed. The bearing is preload-set at manufacture rather than clearance-set.

Because angle and preload are independent choices, the same 25 x 47 x 12 mm envelope exists in several genuinely different bearings. A 7005C at 15° with medium preload, as here, is a different part from a 7005A5 at 25° with light preload, even though both drop into identical seats. Matching only bore, outside diameter and width will not distinguish them.

P4 holds bore, outside diameter, width and running accuracy to single-digit micron limits. Radial runout of the assembled inner ring, Kia: 2.5 µm. Radial runout of the assembled outer ring, Kea: 5 µm. Duplex grinding converts those tolerances into the preload itself: the ring faces are relieved by a measured amount, so clamping the pair solid produces the medium preload directly with no shimming.

Quantity and configuration:

Unit Quantity: 2 Pcs, supplied as one matched duplex pair, duplex ground as a set.

Thrust direction:

Each bearing on its own takes thrust in one direction. Back-to-back or face-to-face, the pair takes thrust in both directions; in tandem it takes a larger load in one direction only.

Mounting data:

Inner ring abutment diameter, d1 min: 30 mm. Outer ring abutment diameters: D1 max 42 mm, D2 max 44.5 mm. Chamfer dimensions: r min 0.6 mm, r1 min 0.3 mm. Effective Load Centre (a): 10.8 mm. Internal free volume: 3.8 cm³. PCD of lubrication jets: 32.9 mm. Mass: 0.079 kg per bearing, 0.158 kg per pair.

Interchange guidance:

B7005X2TADUMEP7 is the RHP B-series form of this envelope and angle, and 2MM9105WI is the Fafnir-scheme number for the same 15° 70-series size. NSK 7005CTRDUMP4 is the current NSK-RHP catalogue designation, and FAG B7005-C-T-P4S-DUM is the Schaeffler execution at P4S grade. Same-envelope bearings differing in contact angle, preload grade or tolerance class — 7005A5 at 25°, the light and heavy preload sets, and P0 or P3 class variants — are related sizes rather than interchanges. A single universally faced bearing of this size is a different item, since SU pieces are not ground to this pair’s stack height.