Fafnir2MM9120WIDUMSuper-Precision Angular Contact Bearing Matched Pair 100x150x24 mm 15° Medium Preload ABEC 7/9

Product Description

What this part is

A Fafnir 2MM9120WI-DUM matched duplex pair of super-precision single-row angular contact ball bearings. Each bearing is 100 mm bore, 150 mm outside diameter, 24 mm wide, giving 48 mm total stack width. Open on both faces, universally ground as a set.

Decoding the designation

2MM — 15° contact angle in the Fafnir scheme; the MM prefix carries the P4S build9120 — leading 9 marks the ISO 70 light series, 100 mm bore, so the ISO equivalent is 7020-CWI — super-precision spindle bearing seriesDU — duplex, ground as a matched setM — medium preload

What these specs mean in practice

Medium preload sits between the light grade used for the highest speeds and the heavy grade used where deflection under cut matters most, giving a working balance of stiffness and running temperature. The 15° angle favours speed and radial stiffness over thrust. As a duplex set the preload arrives ground in, with no shims to fit.

Published specifications

Bore: 100 mmOutside diameter: 150 mmWidth: 24 mm per bearing, 48 mm stackedContact angle: 15°Precision: P4S — ABEC 7 / ABEC 9Preload: medium, factory matchedRows: 1 per bearingClosure: open

Quantity and configuration

Matched duplex pair. 2 Pcs per sale unit.

Fitting notes

Each bearing carries thrust in one direction; the pair mounted back-to-back or face-to-face covers both. The etched marks on the outer rings align to hold the matched offset as ground.

Interchange guidance

Same-spec matched pairs at 15°, super precision, medium preload: RHP 7020CTDUMP4, FAG B7020C.T.P4S.UM, SKF 7020 CD/P4ADGB, NSK 7020CTRDUMP4. The 25° 3MM9120WI and RHP 7020ETDUM share the envelope at a different contact angle and are related sizes rather than interchanges.