Fafnir3MM9106WIDULAngular Contact Ball Bearing – 30 mm ID, 55 mm OD, 13 mm Width, Open, 25°, Light Preload, Universal Duplex Pair

Product Description

What this part is

Fafnir 3MM9106WI-DUL super-precision angular contact ball bearing, supplied as a universally ground matched duplex pair. Bore 30 mm, outside diameter 55 mm, width 13 mm per bearing, 26 mm across the pair. ISO equivalent size 7006. Fafnir is a Timken brand.

Decoding the designation

The 3MM prefix gives a 25° contact angle, and the MM series is built to P4S, equivalent to ABEC 7 dimensional tolerances with ABEC 9 running accuracy. 9106 is the Fafnir series code for the ISO 7006 size. WI is the super-precision angular contact execution. DUL is a duplex universal set at light preload.

What these specs mean in practice

The 25° contact angle puts this in the thrust-biased half of the range: it carries more axial load and gives higher axial rigidity than a 15° bearing of the same size, at some cost in speed capability. Timken lists the 3MM series for thrust-dominated spindle work such as vertical rotary surface grinders, disc grinders and heavy-duty lathe thrust positions. Dynamic capacity is 14.3 kN, static capacity 10.3 kN, limiting speed 23,000 rpm, and the phenolic cage sets the upper temperature limit at 121 °C.

Quantity and configuration

Two bearings, matched as one set, 0.53 lbs per bearing. Universal grinding allows back-to-back, face-to-face or tandem arrangement, with preload established as the ground ring faces are clamped together.

Preload and clearance

Light preload, ground into the ring faces. A preloaded matched pair has no operating radial internal clearance, so clearance classes such as CN do not apply.

Fitting notes

Each outer ring carries a V mark across the outside diameter; the marks are aligned to hold the intended arrangement. Shaft and housing seats are held to precision tolerances, and both bearings are clamped as one unit against a common shoulder. Oil lubrication suits the phenolic cage.

Interchange guidance

FAG B7006-E-T-P4S-DUL is a same-specification interchange — E on a B70 designation is a 25° contact angle, T is the phenolic cage, DUL the duplex universal light-preload arrangement. NSK 7006A5TYNDULP4 matches size, angle and arrangement with a polyamide ball-guided cage. SKF 7006 ACD/P4ADGA is the same envelope and angle as a universal matched pair at extra-light preload, so the preload class differs.