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Fine Thread All-Metal Lock Nut Dimensions (ISO 10513, M8 to M36)
Guide · Updated October 28, 2026
ISO 10513 covers prevailing torque all-metal hexagon high nuts with metric fine pitch thread, no flange. Hex, corners and bearing face match ISO 8674 style 2, and h min equals the ISO 8674 m min. Values come from the ISO 10513:2012 preview table, checked against the 164580.com ISO 10513:2025 table and our ISO 8674 chart (s, e, dw and h min). All three agree on every value shown. Two documented edition changes: M12 h max 13.30 mm (2012 typo) is 12.30 mm in 2025, and M24 h max went from 23.90 to 24.00 mm; we show 2025 values. Not shown: da, because the 2025 edition changed it to two decimals and the editions differ slightly. Non-preferred sizes M14, M18, M22, M27, M33 and M39 are left out because our third source does not cover them.
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Step by step
- Confirm fine pitch: ISO 10513 is fine pitch: M8x1, M10x1.25, M12x1.5, M16x1.5, M20x2, M24x2. For coarse thread use ISO 7042.
- Pick the wrench: Same hex as ISO 8674: 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 locking crown: M8 8.00 mm, M12 12.30 mm, M20 20.30 mm.
- Check wrench grip: mw min is the hex height you can grip: M12 8.30 mm. Use a full six-point socket.
- Leave thread past the nut: Run at least 2 full threads past the top so the deformed locking threads are fully engaged.
- Pick it for heat: No nylon insert, so it suits hot spots where a nylon lock nut would soften.
ISO 10513 fine thread all-metal lock nut dimensions (mm)
Columns: thread size x pitch (first pitch preferred), width across flats s max and min (s max is the wrench size), total height h max and min, wrenching height mw min, width across corners e min, bearing face diameter dw min.
- Size | s max | s min | h max | h min | mw min | e min | dw min
- M8x1 | 13.00 | 12.73 | 8.00 | 7.14 | 5.15 | 14.38 | 11.63
- M10x1.25 / M10x1 | 16.00 | 15.73 | 10.00 | 8.94 | 6.43 | 17.77 | 14.63
- M12x1.5 / M12x1.25 | 18.00 | 17.73 | 12.30 | 11.57 | 8.30 | 20.03 | 16.63
- M16x1.5 | 24.00 | 23.67 | 16.40 | 15.70 | 11.28 | 26.75 | 22.49
- M20x2 / M20x1.5 | 30.00 | 29.16 | 20.30 | 19.00 | 13.52 | 32.95 | 27.70
- M24x2 | 36.00 | 35.00 | 24.00 | 22.60 | 16.16 | 39.55 | 33.25
- M30x2 | 46.00 | 45.00 | 30.00 | 27.30 | 19.44 | 50.85 | 42.75
- M36x3 | 55.00 | 53.80 | 36.00 | 33.10 | 23.52 | 60.79 | 51.11
Worked example: bolt length for an M12x1.5 all-metal lock nut
Grip 20 mm, washer 2.5 mm, nut h max 12.30 mm, plus 2 threads at 1.5 mm = 3 mm. Total 37.8 mm, so an M12x1.5 x 40 works.
Common problems
- Coarse bolt, fine nut: it starts, then binds. Check pitch first.
- Galling: all-metal lock nuts on stainless bolts can seize. Lubricate and run them on slowly.
- M10 and M12 come in two fine pitches. Read the label.
FAQ
What is the difference between ISO 10513 and ISO 7042?
\nBoth are all-metal prevailing torque hex lock nuts with no flange. ISO 7042 is coarse thread (M12x1.75); ISO 10513 is fine pitch (M12x1.5 or M12x1.25). The hex is the same except M10, where both use 16 mm.
\nWhat is the difference between ISO 10513 and ISO 8674?
\nISO 8674 is the plain fine thread style 2 high nut. ISO 10513 has the same hex, corners and bearing face plus an all-metal locking feature. h min matches ISO 8674 m min.
\nWhat is the difference between ISO 10513 and ISO 12126?
\nISO 12126 is a fine pitch all-metal lock nut with a built-in flange. ISO 10513 has no flange, so use a washer if you need load spread.
\nWhy does M12 h max differ between editions?
\nThe 2012 edition printed 13.30 mm; the 2025 edition says that was a typing error and corrects it to 12.30 mm. M24 h max went from 23.90 to 24.00 mm. We show the 2025 values.
\nWhat wrench fits an M16x1.5 all-metal lock nut?
\n24 mm.
\nCan I reuse an all-metal lock nut?
\nPrevailing torque drops each time. Replace nuts on critical joints.
\nRelated guides and calculators
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- Hex weld nut with flange dimensions (ISO 21670)
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- High hex nut dimensions (ISO 4033)
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- Fine thread hex flange nut dimensions (ISO 10663)
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- Nylon insert flange lock nut dimensions (ISO 7043)
- Fine thread nylon insert lock nut dimensions (ISO 10512)
- All-metal lock nut dimensions (ISO 7042)
- Fine thread high hex nut dimensions (ISO 8674)
- Fine thread all-metal flange lock nut dimensions (ISO 12126)
- Fine thread nylon insert flange lock nut dimensions (ISO 12125)
- Nylon insert lock nut dimensions (ISO 7040)
- Thin nylon insert lock nut dimensions (ISO 10511)
- All-metal flange lock nut dimensions (ISO 7044)
- Fine thread hex nut dimensions (ISO 8673)
- Wrench size chart for bolts and nuts
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