Fafnir3MM9316WISULSuper Precision Angular Contact Ball Bearing – Straight Bore, 80 mm ID, 110 mm OD, 16 mm Width, Open, 25° Contact Angle, Light Preload, Phenolic Outer-Land-Riding Cage, ISO P4S

Product Description

What this part is

Fafnir 3MM9316WI SUL super precision angular contact ball bearing, single row, 9300WI spindle series. Manufacturer Part Number: 3MM9316WI SUL. World Part Number: 71916E-T-P4S-SUL. Bore: 80 mm. Outside Diameter: 110 mm. Bearing Width: 16 mm. Total Width: 16 mm. Number Of Rows: 1. Bore Type: Straight. Closure Type: Open. Rolling Elements: Steel balls. Design Units: Metric.

Decoding the designation

Contact Angle: 25°, carried by the 3MM prefix. Series: 9300WI, which maps to the ISO 719xx extra-light section, so the 9316 is a 71916 envelope at 80 x 110 x 16 mm. WI: low shoulder on both rings. CR: phenolic outer land riding cage. SU: single universally ground. L: light preload. Precision Class: ISO P4S, equivalent to ABEC 7/9. Preload: Light. Mounting Arrangement: Universal single.

Published ratings

Dynamic Radial Load Rating – 1M Revs (C1): 31,900 N (7,170 lbf). C1 ISO Dynamic Radial Rating, per row: 29,000 N (6,520 lbf). Static Radial Load Rating (C0): 30,500 N (6,860 lbf). Limiting Speed, grease: 11,600 rpm. Limiting Speed, oil: 20,800 rpm. These are single-bearing figures.

Mounting dimensions

Max Shaft Fillet Radius: 1 mm. Outer Ring To Clear Radius: 1 mm. Shaft Backing Shoulder Diameter: 86.1 mm. Housing Backing Shoulder Diameter: 104.4 mm.

What these specs mean in practice

A 25° contact angle puts more of the load line along the shaft axis, so this bearing is stiffer axially than the 15° execution on the same envelope and holds a spindle nose in position under thrust — boring, drilling, plunge milling, heavy face milling. The trade is speed: a steeper angle raises the centrifugal and gyroscopic work on the ball set.

The 719 extra-light section gives a thin cross section for a large bore: 80 mm of bore inside a 110 mm outside diameter and only 16 mm of width. That buys shaft diameter and bending stiffness in a compact spindle nose. Light preload is the setting for speed and low heat generation, and it lets the spindle run cooler at the top of its range. Internal Clearance: N/A — a preloaded bearing is defined by its preload rather than by a clearance class. Lubricant: grease or oil, and Timken publishes a limiting speed for each.

Cage Type: CR, phenolic outer land riding. Cage Material: Phenolic. A machined phenolic laminate cage is light, so it loads the ball pockets very little at speed, it is self lubricating, and it damps rather than rings. Guidance on the outer ring land keeps it stable at high speed.

Quantity and configuration

Unit Quantity: 1 Pc. Rows per Set: single. Universal grinding means one bearing runs alone, or several stack back to back, face to face or in tandem and reach the light preload of the set.

Interchange guidance

Base Number: 71916. MPN Variants: 3MM9316WISUL, 3MM9316WI SUL, 3MM-9316-WI-SUL, 3MM9316WICRSUL, 2MM-9316-WI-CR-SUL, 3MM9316WI, 71916, 7916. Same-envelope 25° light-preload super precision equivalents are written SKF 71916 ACDGA/P4A, FAG B71916-E-T-P4S-UL and NSK 71916A5. Cage material and precision class vary between makers inside those designations. The line passed from Fafnir to Torrington to Timken, and Timken lists 3MM9316WI SUL today.