RHP7203CTDUMP4Super Precision Angular Contact Ball Bearing 17x40x12 mm, 15 Degree Contact Angle, Phenolic Cage, Duplex Universal Medium Preload

Product Description

What this part is

RHP 7203CTDUMP4 super-precision angular contact ball bearing in the 72 series. Bore: 17 mm. Outside Diameter: 40 mm. Width: 12 mm. Contact Angle: 15°. Precision Class: P4, ISO Class 4, ABEC 7. Cage Material: laminated phenolic. Cage Type: machined, outer-ring guided. Closure Type: Open. Preload: Medium. Bore Type: Straight. Number Of Rows: 1 per bearing. Rolling Elements: Ball. Series: 72, ISO dimension series 02. Country of Origin: United Kingdom. A small machine tool spindle bearing, typical of grinding spindles, high-frequency spindles and precision instrument drives.

Decoding the designation

7203 is the ISO 72-series angular contact envelope, 17 x 40 x 12 mm. C denotes a 15° contact angle. T is the machined, outer-ring guided phenolic cage. DUM is duplex universal at medium preload: the ground faces produce the specified preload when the set is clamped together, in whichever arrangement is chosen. P4 is ISO tolerance class 4, equivalent to ABEC 7 and to EP7 in the British Standard BS292 scheme. Searchable forms: 7203CTDUMP4, 7203-C-T-DUM-P4, 7203 C T DUM P4, 7203X2TADUM.

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. Bearing Material: carbon chrome bearing steel to BS970 534A99 / 535A99, equivalent to SAE 52100, through hardened. Lubricant: oil or grease. Design Units: Metric. Harmonization Code: 8482.10.50.28.

What these specs mean in practice

A 15° contact angle biases the bearing toward radial load and speed, running cooler than a steeper angle at the same rev/min and holding radial running accuracy better, at the cost of axial capacity and stiffness. Medium preload raises stiffness and positional accuracy above a light-preload set, at the cost of some heat and speed headroom.

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 DUM matched pair, ground as one original 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.

Interchange guidance

The RHP legacy form is the 7203X2TADUM family, in which X2 confirms the 15° angle and TA the one-piece outer-ring-centred phenolic cage. World-number format is 7203C-T-P4S-DUM; Schaeffler format is B7203-C-T-P4S-DUM; SKF format is 7203 CD/P4ADGB. The Fafnir 15° equivalent envelope is the 2MM203WI family. RHP super-precision production passed to NSK, and the NSK form is 7203CTRDUM.