Fafnir2MM209WICRDUMSuper-Precision Angular Contact Ball Bearing Pair – 45 mm Bore, 85 mm OD, 19 mm Width, 15°, Medium Preload

Product Description

What this part is

Fafnir 2MM209WICRDUM, a super-precision angular contact ball bearing supplied as a universally ground duplex pair. Bore Diameter: 45 mm. Outside Diameter: 85 mm. Overall Width: 19 mm per bearing. Total Width: 38 mm mounted as a pair. Contact Angle: 15°. Rolling Elements: Ball. Number Of Rows: 1 per bearing. Bore Type: Straight. Closure Type: Open. Cage Material: Phenolic. Precision Class: ABEC 7/9 / P4S. Preload: Medium. Series: 200WI. Base Number: 2MM209WI. GTIN: 087796070448.

Decoding the designation

2MM — Fafnir super-precision spindle range at a 15° contact angle, ground to ABEC 7/9 (P4S) tolerances.

209 — 200 medium dimension series, bore code 09, which maps to the ISO 7209 envelope: 45 mm bore, 85 mm outside diameter, 19 mm width.

WI — low shoulder on both rings.

CR — phenolic cage.

DUM — duplex pair, universally ground, medium preload. Either face can be brought together, so the pair mounts back-to-back, face-to-face or in tandem.

What these specs mean in practice

Dynamic Load Rating: 45,200 N per bearing. Static Load Rating: 28,800 N per bearing. Limiting Speed: 17,500 rpm grease; 35,000 rpm oil. Item Weight: 0.816 kg (1.80 lb) for the pair. Internal Clearance: N/A — a preloaded set is clamped to a defined stiffness rather than run to a clearance. Medium preload sits between light and heavy: more spindle stiffness and closer axial location than light, at some cost in running heat. A 15° contact angle favours speed and radial rigidity over thrust capacity.

Mounting data

Shaft Backing Shoulder Diameter: 52.3 mm. Housing Backing Shoulder Diameter: 78.2 mm. Maximum Housing Fillet Radius: 1 mm (0.039 in) — the largest housing corner radius the bearing corners will clear.

Quantity and configuration

Unit Quantity: 2 Pcs. One universally ground duplex pair. The 19 mm figure is the width of a single bearing; the pair occupies 38 mm of shaft length when clamped together.

Interchange guidance

Direct super-precision equivalents on the 7209 envelope at 15° with medium preload: FAG B7209-C-T-P4S-UL, SKF 7209 CD/P4ADGB, NSK 7209CTRDUMP4, NTN 7209UCG/GNP4, RHP 7209CTDUMP4 and Koyo 7209C P4 DUM. SNR 7209CG1DUJ84 is the equivalent French execution. MRC 7209 is a related size only: MRC’s plain 7000 series runs a 29° contact angle. Searchable variants include 2MM209WIDUM, 2MM-209-WI-CR-DUM, 2 MM 209 WI CR DUM and 2MM209WICRDUM.