Fafnir2MM210WIA2DULSuper-Precision Angular Contact Ball Bearing Duplex Pair – Straight Bore, 50 mm ID, 90 mm OD, 20 mm Width, Open, 15° Contact Angle, ABEC 7/9, Light Preload, 2 Pcs

Product Description

What this part is

Fafnir 2MM210WIA2-DUL super-precision angular contact ball bearing set, ISO 7210 envelope, 50 mm bore x 90 mm outside diameter x 20 mm width per bearing. Bore: 50 mm. Outside Diameter: 90 mm (3.543 in). Overall Width: 20 mm (0.787 in). Total Width: 40 mm across the pair. Bore Type: Straight. Number Of Rows: 1 per bearing. Rolling Elements: Steel balls. Closure Type: Open. Contact Angle: 15°. Precision Class: ABEC 7/9 (ISO P4S). Preload: Light. Cage Material: Machined laminated phenolic. Cage Type: Outer-ring land-riding, machined. Design Units: Metric. Material: Chrome bearing steel. Country of Origin: United States.

Decoding the designation

2MM: 15° contact angle in Timken’s Fafnir super-precision scheme, and the MM prefix carries ISO tolerance class P4S, equal to ABEC 7/9. 210: the 200WI medium series, which maps to ISO 7210. WI: super-precision spindle execution. DU: universally faced duplex pair. L: light preload. Timken’s own world part number for this set is 7210C-T-P4S-DUL. Searchable variants: 2MM-210-WI-A2-DUL, 2MM210WI A2 DUL, 2 MM 210 WI A2 DUL, 2MM210WICRDUL, 7210C, 7210C-T-DUL-P4.

What these specs mean in practice

Dynamic Radial Load Rating, set: 47,400 N (10,700 lbf). Dynamic Radial Load Rating per row, ISO C1: 43,100 N (9,730 lbf). Static Radial Load Rating: 31,700 N (7,130 lbf). Limiting Speed, grease lubrication: 16,000 rpm. Limiting Speed, oil lubrication: 32,000 rpm. The 200WI medium series puts a larger ball complement on the 50 mm bore than the 9100 light series, so the load ratings are substantially higher in the same shaft size. A 15° contact angle favours speed and radial stiffness over thrust capacity. The machined phenolic cage rides on the outer-ring land, so cage guidance comes from the stationary ring and stays stable as speed rises. Lubricant: grease or oil. Maximum Operating Temperature: 120 °C. Minimum Operating Temperature: -30 °C.

Quantity and configuration

Unit Quantity: 2 Pcs. Rows Per Set: Duplex. A matched pair with universally ground faces, so the two bearings mount back-to-back, face-to-face or in tandem and reach light preload when clamped. Internal Clearance: N/A — face grinding sets the axial position on a universally faced preloaded set, in place of a radial clearance class.

Fitting notes

Shaft Backing Shoulder Diameter: 57.4 mm (2.260 in). Housing Backing Shoulder Diameter: 83.3 mm (3.280 in). Maximum Shaft Fillet Radius: 1 mm (0.039 in). Outer Ring To-Clear Radius: 1 mm (0.039 in).

Interchange guidance

Same-specification equivalents: Timken world part number 7210C-T-P4S-DUL, NSK 7210CTRDULP4, SKF 7210 CD/P4ADGA, FAG B7210-C-T-P4S-UL, RHP 7210CTDULP4. A 3MM210WI set shares the 50 x 90 x 20 mm envelope at a 25° contact angle, which is a related size rather than a substitution.