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High Nylon Insert Lock Nut Dimensions (ISO 7041, M5 to M36)
Guide · Updated October 28, 2026
ISO 7041 covers prevailing torque hexagon high nuts with a non-metallic (nylon) insert and metric coarse thread. Height is the ISO 4033 style 2 m min plus the insert. Values come from the ISO 7041:2012 preview table, checked against the globalfastener ISO 7041-2012 table and the StainlessFix ISO 7041 table (s, h, m for M5 to M24). All agree on every value shown. M30 and M36 use the ISO and globalfastener tables, with s, e and dw matching our ISO 4033 chart. ISO 7041:2025 raised the M5 height and changed its bearing face, so M5 h and dw are left blank. Not shown: da and the non-preferred M14.
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Step by step
- Confirm coarse thread: ISO 7041 is coarse pitch: M6x1, M8x1.25, M10x1.5, M12x1.75, M16x2, M20x2.5. For fine pitch use ISO 10512.
- Pick the wrench: Same hex as ISO 7040 and ISO 4033: M8 13 mm, M10 16 mm, M12 18 mm, M16 24 mm, M20 30 mm, M24 36 mm.
- Use total height for length: h max includes the nylon ring: M8 10.20 mm, M12 16.10 mm, M20 25.10 mm.
- Check thread height: m min is the metal thread length, same as an ISO 4033 high nut: M12 11.57 mm.
- Leave thread past the nut: Run at least 2 full threads past the top of the nylon ring so the insert grips.
- Keep it cool: The nylon insert is for service up to about 120 C. For hot spots use an all-metal nut such as ISO 7042.
ISO 7041 high nylon insert lock nut dimensions (mm)
Columns: thread size, width across flats s max and min (s max is the wrench size), total height h max and min, thread height m min, wrenching height mw min, width across corners e min, bearing face diameter dw min. A dash means the value changed in ISO 7041:2025 and is left blank.
- Size | s max | s min | h max | h min | m min | mw min | e min | dw min
- M5 | 8.00 | 7.78 | — | — | 4.80 | 3.84 | 8.79 | —
- M6 | 10.00 | 9.78 | 8.50 | 7.92 | 5.40 | 4.32 | 11.05 | 8.88
- M8 | 13.00 | 12.73 | 10.20 | 9.50 | 7.14 | 5.71 | 14.38 | 11.63
- M10 | 16.00 | 15.73 | 12.80 | 12.10 | 8.94 | 7.15 | 17.77 | 14.63
- M12 | 18.00 | 17.73 | 16.10 | 15.40 | 11.57 | 9.26 | 20.03 | 16.63
- M16 | 24.00 | 23.67 | 20.70 | 19.40 | 15.70 | 12.60 | 26.75 | 22.49
- M20 | 30.00 | 29.16 | 25.10 | 23.00 | 19.00 | 15.20 | 32.95 | 27.70
- M24 | 36.00 | 35.00 | 29.50 | 27.40 | 22.60 | 18.10 | 39.55 | 33.25
- M30 | 46.00 | 45.00 | 35.60 | 33.10 | 27.30 | 21.80 | 50.85 | 42.75
- M36 | 55.00 | 53.80 | 42.60 | 40.10 | 33.10 | 26.50 | 60.79 | 51.11
Worked example: bolt length for an M12 high nylon lock nut
Grip 20 mm, washer 2.5 mm, nut h max 16.10 mm, plus 2 threads at 1.75 mm = 3.5 mm. Total 42.1 mm, so an M12 x 45 works.
Common problems
- DIN 982 stock with 17 or 19 mm hex mixed in with ISO 16 or 18 mm. Check the wrench.
- Heat: nylon softens near exhausts and engines. Use an all-metal nut there.
- Too short a bolt: the insert never engages and the nut can back off.
FAQ
What is the difference between ISO 7041 and ISO 7040?
Same hex, same insert. ISO 7041 has the taller style 2 (high) metal body from ISO 4033, so it has more thread engagement: M12 h max 16.10 mm vs 14.90 mm for ISO 7040.
Is ISO 7041 the same as DIN 982?
Close but not identical. Old DIN 982 nuts often have different heights and some different hex sizes (M10 17 mm, M12 19 mm). Check the hex before buying a wrench.
What is the difference between ISO 7041 and ISO 7042?
ISO 7042 is the all-metal high lock nut. It handles heat better; ISO 7041 uses a nylon ring and is gentler on threads.
Why use a high nylon lock nut?
The taller metal body gives more thread engagement, so it suits higher strength bolts where a regular nut could strip.
What wrench fits an M16 high nylon lock nut?
24 mm.
What changed in ISO 7041:2025?
It added M7, M18, M22, M27, M33 and M39, raised the M5 height and changed the M5 bearing face. We leave M5 h and dw blank until we can confirm the new values.
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- Nylon insert lock nut dimensions (ISO 7040)
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- All-metal lock nut dimensions (ISO 7042)
- Thin nylon insert lock nut dimensions (ISO 10511)
- Fine thread nylon insert lock nut dimensions (ISO 10512)
- Fine thread all-metal lock nut dimensions (ISO 10513)
- Nylon insert flange lock nut dimensions (ISO 7043)
- Metric hex nut size chart (ISO 4032)
- Metric jam nut size chart (ISO 4035)
- Wrench size chart for bolts and nuts
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