Fafnir2MM218WI-DULSuper Precision Angular Contact Ball Bearing 90x160x30 mm, 15° Contact Angle, Duplex Light Preload, Phenolic Cage, 2 Pcs

Product Description

What this part is

Fafnir 2MM218WI-DUL super-precision angular contact ball bearing, supplied as a universally ground duplex pair. Bore: 90 mm. Outside Diameter: 160 mm. Bearing Width: 30 mm. Total Width: 60 mm. Series: Fafnir 200WI spindle series, ISO 7218 envelope. Timken World Part Number: 7218C-T-P4S-DUL. Rolling Elements: steel balls. Cage Type: CR – Phenolic Outer Land Riding Cage. Closure Type: open on both faces.

Decoding the designation

2MM is the Fafnir super-precision prefix. Contact Angle: 15°, where a 3MM prefix sets 25°. Precision Rating: ISO P4S (ABEC 7/9). The absence of a leading 9 in 218 places the bearing in the ISO 72 dimension series rather than the lighter 70 series, which is why the outside diameter is 160 mm and not the 140 mm of a 7018. WI identifies the super-precision angular contact family and CR marks the phenolic cage riding on the outer ring land. DU is a universally ground duplex pair and L is light preload. Preload: Light. Searchable forms of the number include 2MM218WI-DUL, 2MM218WIDUL, 2MM218WI CR DUL and 2MM 218 WI DUL.

What these specs mean in practice

Dynamic Radial Load Rating (C1, set): 129.9 kN / 29,200 lbf. Dynamic Radial Load Rating (C1, per row): 118 kN / 26,500 lbf. Static Radial Load Rating (C0): 97.9 kN / 22,000 lbf. Limiting Speed, grease: 8,900 rpm. Limiting Speed, oil: 17,800 rpm. A 15° contact angle carries less thrust and permits higher speed than a 25° angle. Light preload eliminates internal clearance while keeping running torque and heat generation low, which suits high-speed spindle positions where thermal growth governs. A phenolic cage riding on the outer land has low mass and a favourable friction pair against steel, and it retains oil in the cage material, which is why the CR cage is standard on high-speed super-precision spindle bearings.

Mounting dimensions

Shaft Backing Shoulder Diameter: 102.7 mm (4.05 in). Housing Backing Shoulder Diameter: 148 mm (5.830 in). Maximum Shaft Fillet Radius: 2 mm (0.079 in). Outer Ring To Clear Radius: 2 mm (0.079 in).

Quantity and configuration

Two bearings, one duplex pair ground for light preload. Unit Quantity: 2 Pcs. Arrangement: universally ground, mountable back to back, face to face or in tandem, reaching the designed preload when the pair is clamped solid against the flush ground faces.

Interchange guidance

Same-spec equivalents in the 7218 C P4 DUL forms are FAG B7218-C-TPA-P4S-UL, SKF 7218 CD/P4A in a light-preload duplex arrangement, NSK 7218 CTR DUL P4 and RHP 7218CTDULP4. The Barden 218HDL is the equivalent in the Barden inch-scheme numbering. A 7218 AC or A5 variant is a related size at 25° or 30° and changes the thrust and speed balance, so it is a related size rather than a substitution.