Fafnir2MM9128WI SULSuper-Precision Angular Contact Ball Bearing 140x210x33 mm 15° Light Preload ABEC 7/9

Product Description

What this part is:

A Fafnir 2MM9128WI-SUL super-precision single-row angular contact ball bearing. Bore 140 mm, outside diameter 210 mm, width 33 mm. Open on both faces, universally ground.

Decoding the designation:

• 2MM — 15° contact angle in the Fafnir scheme; the MM prefix carries the P4S build
• 9128 — leading 9 marks the ISO 70 light series, 140 mm bore, so the ISO equivalent is 7028-C
• WI — super-precision spindle bearing series
• SU — single universally ground
• L — light preload

What these specs mean in practice:

P4S covers ABEC 7 dimensional tolerance with ABEC 9 running accuracy. At 140 mm bore the 70 light section keeps the outside diameter down and the speed ceiling up compared with a 72-series bearing on the same shaft. The 15° angle favours speed and radial stiffness; light preload runs coolest of the three grades.

Published specifications:

• Bore: 140 mm
• Outside diameter: 210 mm
• Width: 33 mm
• Contact angle: 15°
• Precision: P4S — ABEC 7 / ABEC 9
• Preload: light
• Rows: 1
• Closure: open

Quantity and configuration:

Single universally ground bearing. 1 Pc per sale unit.

Fitting notes:

Thrust is carried in one direction only, so the bearing runs against an opposing bearing or a housing shoulder. The wide outer-ring land is the thrust face and its orientation sets the arrangement.

Interchange guidance:

Same-spec equivalents at 15°, super precision, light preload: RHP 7028CTSULP4, FAG B7028C.T.P4S.UL, SKF 7028 CD/P4A, NSK 7028CTRSULP4. The 25° 3MM9128WI and FAG B7028E share the envelope at a different contact angle and are related sizes rather than interchanges.