RHP7203CTDUMP4Super Precision Angular Contact Ball Bearing Matched Pair 17x40x12 mm 15 Degree ABEC 7 Medium Preload

Product Description

What this part is

RHP 7203CTDUMP4, a duplex-ground matched pair of single-row super-precision angular contact ball bearings. Bore: 17 mm. Outside Diameter: 40 mm. Width: 12 mm each. Total Width: 24 mm, pair clamped. Contact Angle: 15°. Precision Class: P4, ABEC 7, ISO Class 4. Preload: Medium. Cage Material: laminated phenolic. Cage Type: machined, outer-ring guided. Closure Type: Open, both faces. Bore Type: Straight. Number Of Rows: 1 per bearing. Rolling Elements: Ball. Series: 72, ISO dimension series 02. Design Units: Metric. Country of Origin: United Kingdom.

Decoding the designation

The 72 prefix and bore code 03 give ISO dimension series 02 at a 17 mm bore. C is a 15° contact angle. T is a machined laminated phenolic cage, outer-ring guided. DU is duplex universal face control. M is the medium preload grade. P4 is super-precision tolerance to ABEC 7 and ISO Class 4. The Fafnir-scheme number 2MM203WI carried on the carton gives the same angle, since the 2MM prefix is 15°.

Published ratings and speeds

Basic Dynamic Load Rating (Cr): 10.9 kN (10 900 N), single bearing. Basic Static Load Rating (C0r): 5.85 kN (5 850 N), single bearing. Limiting Speed, oil/air lubrication: 58 800 rev/min. Limiting Speed, grease lubrication: 36 400 rev/min. Axial Preload: 150 N, medium, as a paired set. Axial Stiffness: 42 N/µm for a medium-preload pair. Effective Load Centre (a): 9.8 mm. Maximum Operating Temperature: 120 °C. Lubricant: oil or grease. Bearing Material: carbon chrome bearing steel to BS970 534A99 / 535A99, equivalent to SAE 52100, through hardened. Harmonization Code: 8482.10.50.68.

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, trading axial capacity and axial stiffness to get there.

Medium preload sits between the light and heavy grades. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable; the friction it adds becomes heat, and that heat shifts the preload as the spindle warms. The M grade buys more axial and radial stiffness than L at the cost of more heat, which suits a spindle carrying real cutting load rather than one chasing maximum speed.

P4 holds bore, outside diameter, width and running accuracy to single-digit micron limits: inner ring radial runout Kia 2.5 µm, outer ring radial runout Kea 5 µm. Universal face control turns those tolerances into the preload itself, so clamping the pair solid produces the medium preload directly.

Speed factors applied to the single-bearing limiting speed, medium preload: back-to-back pair 0.60, set of three 0.50, set of four 0.45. Face-to-face mounting applies a further 50 percent reduction. A spring-loaded tandem pair takes a factor of 0.95.

Quantity and configuration

Unit Quantity: 2 Pcs. A matched pair, duplex ground as one set, mountable back-to-back, face-to-face or in tandem at the specified preload.

Mounting data

Shaft Abutment Diameter (d1 min): 22 mm. Housing Abutment Diameters: D1 max 35 mm, D2 max 37.5 mm. Bearing Fillet Radius (r min): 0.6 mm. Secondary Fillet Radius (r1 min): 0.3 mm. Lubrication Jet Pitch Circle Diameter (dT): 25.9 mm. Internal Free Volume: 3.1 cm³ per bearing. Mass: 0.065 kg per bearing, 0.130 kg for the pair. Recommended shaft limits at P4: +2 / -2 µm, a mean 2T interference fit. Recommended housing limits at P4 for a locating bearing: +5 / 0 µm, a mean 5C clearance fit.

Interchange guidance

B7203CTP4S is the RHP B-series form of this envelope and angle. 7203 CD/P4ADGB is the SKF-scheme equivalent. B7203-C-T-P4S-DUM is the Schaeffler form. 2MM203WI is the Fafnir designation. NSK, which now builds this range, writes it 7203CTRDUM. Same-envelope bearings differing in contact angle, preload grade or tolerance class — 7203E at 25°, the light and heavy preload sets, and P0 or P5 class variants — are related sizes rather than interchanges.