NK100-36-XL bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the NK100-36-XL model number is decoded

envelope 100×120×36 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 100 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 3,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 3.47 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 715 g, just 0.17 g per mm² of projected 120×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 100 mm bore the 120 mm outside diameter and 36 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min Omitting the inner ring frees radial space — at a 100 mm shaft the outer diameter is only 120 mm and the width 36 mm, yet C is 125 kN The hardness requirement is unforgiving: below about 58 HRC the 100 mm journal brinels under the 237 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 42.5 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 100 mm seat, and in gearbox selector and change linkages the 715 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 36 mm width and the published 237 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.