NK19-20-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 NK19-20-XL model number is decoded

envelope 19×27×20 mm: 19 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 18.7 kN and C0 23.6 kN at the 19 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 27 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 21,600 r/min and the thermal reference speed 13,400 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 0.98 kN/mm and per millimetre of width 0.93 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 32.2 g, just 0.06 g per mm² of projected 27×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 19 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 19 mm shaft the outer diameter is only 27 mm and the width 20 mm, yet C is 18.7 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 4.2 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 27 mm outside diameter and 18.7 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 19 mm seat, and in hydraulic and pneumatic pump eccentrics the 32.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 23.6 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.