RHP7008ETDUMP4Super Precision Angular Contact Ball Bearing – Straight Bore, 40 mm ID, 68 mm OD, 15 mm Width, Open, 25° Contact Angle, Medium Preload, ABEC 7 / P4

Product Description

What this part is

RHP 7008ETDUMP4-1/2PR super-precision single-row angular contact ball bearing. Bore: 40 mm. Outside Diameter: 68 mm. Width: 15 mm. Contact Angle: 25°. Precision Class: P4, equivalent to ABEC 7 and ISO Class 4. Dynamic Load Rating: 19.5 kN. Static Load Rating: 15.1 kN. Cage Material: Laminated phenolic resin. Cage Type: Outer ring guided. Bore Type: Straight. Closure Type: Open. Rolling Elements: Steel balls. Number Of Rows: 1. Series: 7000, ISO dimension series 10.

Decoding the designation

7008 is the type and size: single-row angular contact, ISO dimension series 10, bore code 08 for a 40 mm bore. E sets the contact angle at 25°. T is the outer-ring-guided laminated phenolic resin cage. DU marks a universally ground paired unit and M sets medium preload. P4 is the precision grade. The trailing 1/2PR identifies one bearing out of that duplex pair. Searchable variants of the number: 7008E, 7008-E-T-DUM-P4, 7008 ET DUM P4, B7008X3TADUMEP7, B7008X3TAUMEP7, 3MM9108WI CR DUM.

What these specs mean in practice

Limiting Speed: 29,700 r/min on oil-air lubrication and 18,400 r/min on grease. The two figures are the published pair for a single bearing under light external load. A 25° contact angle carries more thrust than the 15° execution in the same envelope and gives up some speed for it: the 15° 7008C runs 34,000 r/min on oil-air against 29,700 here. Preload: Medium, 440 N axial. Axial Stiffness: 168 N/µm. Medium preload raises spindle rigidity over the light grade and lowers the speed a mounted pair will hold. Internal Clearance: N/A, as preload and mounted clearance are set against one another. Maximum operating temperature for a laminated phenolic resin cage is 120 °C. Item weight: 0.189 kg (0.42 lbs).

Mounting dimensions

Shaft abutment diameter d1: 46 mm minimum. Housing abutment diameter D1: 62 mm maximum. Outer ring abutment D2: 63 mm maximum. Chamfer r: 1.0 mm minimum. Chamfer r1: 0.6 mm minimum. Effective Load Centre a: 20.1 mm. Internal volume: 8.2 cm³, the figure grease quantity is calculated from. Bearing tolerances are to P4: bore deviation −5 µm, radial runout of the assembled inner ring 4 µm.

Quantity and configuration

Unit Quantity: 1 Pc. One bearing from a factory-matched duplex pair, ground to medium preload. Universal face control means the inner and outer rings are the same width and the faces are ground at manufacture to the specified preload, so it pairs back-to-back, face-to-face or in tandem with another bearing of the same designation without ground spacers. The high point of radial runout is marked with a burnished spot on the inner ring face and a V line on the outer ring diameter, and the V line also indicates the direction of the contact angle.

Interchange guidance

Cross-references: SKF 7008 ACD/P4ADGB, FAG B7008-E-T-P4S-DUM, NSK 7008A5TRDUMP4. Each names the 25° phenolic-caged execution in its own maker’s scheme, so all three are like-for-like on angle, cage, envelope and precision. The 15° 7008C shares the same 40 x 68 x 15 mm envelope and is a related size rather than a substitution, since angle sets both the thrust capacity and the speed limit.