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Thin Nylon Insert Lock Nut Dimensions (ISO 10511 / DIN 985, M3 to M36)

Guide · Updated October 28, 2026

ISO 10511 covers prevailing torque hexagon thin nuts with a non metallic (nylon) insert, the metric thin nyloc that replaced DIN 985. The body is an ISO 4035 jam nut (style 0) plus the nylon ring, so it saves height where a regular ISO 7040 nyloc will not fit. The table gives coarse pitch, width across flats s (wrench size), total height h max and min, metal height m min, width across corners e min and bearing face dw min. Values agree between the ISO 10511:2012 table, the Nufast ISO 10511 production drawing and the fasten.it DIN EN ISO 10511 sheet. ISO 10511:2025 added in between sizes and moved M3 and M4 to an annex, so check your supplier for critical work.

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Step by step

  1. Match the thread: Check diameter and pitch with a thread gage. This chart is coarse pitch M3 to M36, the thin (jam height) nut with a nylon ring.
  2. Pick the wrench: Across flats s is the same as ISO 7040 and ISO 4032: M6 10 mm, M8 13 mm, M10 16 mm, M12 18 mm. Older DIN 985 stock is often 17 mm at M10 and 19 mm at M12.
  3. Check the height: Total height h max is what you need under a cover or inside a pocket. An M10 thin nyloc is 8.56 mm max vs 11.90 mm for ISO 7040.
  4. Respect the load limit: Thin nuts carry less load and are not designed to resist thread stripping. Use them on light clamping, pivots and adjusters, not on bolts torqued to full preload.
  5. Leave thread past the nut: Run at least 2 full threads past the nylon ring so the insert is fully engaged.
  6. Watch the heat: Nylon inserts are generally rated to about 120 C. Above that, use an all metal prevailing torque nut.

ISO 10511 thin nylon insert lock nut dimensions (mm)

Columns: thread size, coarse pitch P, width across flats s (max, the wrench size), total height h max, h min, metal height m min, width across corners e min, bearing face diameter dw min. Grade A through M16, grade B above.

Thin vs regular nyloc height

Total height h max, ISO 10511 thin vs ISO 7040 regular: M6 6.00 vs 8.00 mm, M8 6.76 vs 9.50 mm, M10 8.56 vs 11.90 mm, M12 10.23 vs 14.90 mm, M16 12.42 vs 19.10 mm, M20 14.90 vs 22.80 mm. The nylon ring height (h max minus m min) is the same for both, so all of the saving comes out of the threaded steel.

Worked example: bolt length for an M8 thin nyloc

A pivot through a 6 mm link and a 5 mm bracket with an M8 shoulder or hex screw, one 1.6 mm ISO 7089 washer and an ISO 10511 nut: grip 11 + 1.6 = 12.6 mm, nut h max 6.76 mm, plus 2 threads at 1.25 mm = 2.5 mm. Total 21.9 mm, so an M8 x 25 works. With a regular ISO 7040 nut (9.5 mm) you would need about 24.6 mm, still a 25 but with no spare thread.

Worked example: fitting inside a pocket

A 12 mm deep counterbore holds an M10 nut. ISO 7040 at 11.90 mm plus 3 mm of thread end sticks out. ISO 10511 at 8.56 mm plus 2 threads (3 mm) is 11.56 mm and stays below the surface. Check the 17.77 mm across corners against the pocket and socket wall.

Common problems

FAQ

Is DIN 985 the same as ISO 10511?

Close. ISO 10511 replaced DIN 985 for the thin nylon insert nut, but older DIN 985 stock can use 17 mm at M10, 19 mm at M12 and 22 mm at M14, and the heights differ slightly. Check the box.

What wrench fits an M8 thin nyloc nut?

13 mm. Wrench sizes are the same as a regular ISO 7040 nyloc on the same thread.

Can a thin nyloc nut take full bolt torque?

No. Thin nuts have reduced loadability and are not designed to resist stripping. Use a regular height ISO 7040 nut for a fully preloaded joint.

How tall is an M6 thin nylon lock nut?

6.00 mm max total height, with a minimum metal (threaded) height of 2.90 mm.

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General shop information only — follow your drawing, tool maker's data and your quality system.