ISO 7719

Nylon Insert Lock Nut

Prevailing-torque hexagon nut with a nylon insert — ISO 7719.

Nylon Insert Lock Nut — technical drawing with reference dimensions
dmsedw
Designation d Pitch m (min–max) s e dw Weight /100 Note
M5 common 5.0 0.8 4.8–5.3 8.0 8.79 6.9 0.082 kg Nylon insert — not recommended for reuse after removal.
M6 common 6.0 1 5.4–5.9 10.0 11.05 8.9 0.147 kg Nylon insert — not recommended for reuse after removal.
M8 common 8.0 1.25 6.44–7.1 13.0 14.38 11.6 0.320 kg Nylon insert — not recommended for reuse after removal.
M10 common 10.0 1.5 8.04–9 16.0 17.77 14.6 0.588 kg Nylon insert — not recommended for reuse after removal.
M12 common 12.0 1.75 10.37–11.6 18.0 20.03 16.6 1.005 kg Nylon insert — not recommended for reuse after removal.
M14 14.0 2 12.1–13.2 21.0 23.36 19.6 1.554 kg Nylon insert — not recommended for reuse after removal.
M16 common 16.0 2 14.1–15.2 24.0 26.75 22.5 2.318 kg Nylon insert — not recommended for reuse after removal.
M18 18.0 2.5 15.1–17 27.0 29.56 24.9 3.201 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).
M20 common 20.0 2.5 16.9–19 30.0 32.95 27.7 4.411 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).
M22 22.0 2.5 18.1–21 34.0 37.29 31.4 6.201 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).
M24 common 24.0 3 20.2–23 36.0 39.55 33.3 7.858 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).
M30 common 30.0 3.5 24.3–26.9 46.0 50.85 42.8 15.670 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).
M36 common 36.0 4 29.4–32.5 55.0 60.79 51.1 27.500 kg ISO 7719 property class B (wider tolerances, sizes ≥ M18).

All dimensions in mm. Weight figures are indicative (steel), per 100 pieces.

Glossary

d
Nominal (major) diameter
m
Nut height
s
Wrench size (across flats)
e
Circumscribed diameter (across corners)
dw
Bearing face diameter

Frequently asked questions

What standard governs the nylon insert lock nut?

ISO 7719 — the dimensions in the table below (nominal diameter, thread pitch and all fixed geometry) are taken directly from that standard.

Are these dimensions in millimetres?

Yes — all values are in mm, matching the metric ISO/UNI standards these components are drawn from. There are no imperial variants in this table.

Why do some sizes have a note about property class B?

Above a certain size, these nuts are commonly produced to a coarser property class (B instead of A) — wider manufacturing tolerances, still fully compliant with the standard. It only affects manufacturing tolerance, not how you use the nut.

References & further reading

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