NK6-12-TV-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 NK6-12-TV-XL model number is decoded

envelope 6×12×12 mm: 6 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.0 mm radial section packed with small-diameter needle rollers C is 3.8 kN and C0 3.15 kN at the 6 mm seat; the C/C0 ratio of 1.21 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 12 mm outside diameter the fatigue load limit Cur is 0.53 kN, the limiting speed 36,500 r/min and the thermal reference speed 47,500 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 0.63 kN/mm and per millimetre of width 0.32 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.7 g, just 0.04 g per mm² of projected 12×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 6 mm bore sits in the miniature band; at 12 mm wide the NK6/12-TV-XL is built into compact cam drives, indexing pawls and light linkages The thin 3.0 mm section makes the 5.7 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.53 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 36,500 r/min. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 12 mm outside diameter and 3.8 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 6 mm seat, and in planetary gear bearings the 5.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 12 mm width and the published 3.15 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• 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.
• Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.