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Fine Thread Hex Head Screw Dimensions (ISO 8676 / DIN 961, M8x1 to M30x2)
Guide · Updated October 28, 2026
ISO 8676 covers fully threaded hexagon head screws with metric fine pitch thread, M8 x 1 to M64 x 4, product grades A and B; it replaced DIN 961. This chart shows the preferred threads M8 x 1 to M30 x 2. Values agree across the ISO 8676:2011 published table, the Vipa ISO 8676 datasheet and SpecVise. e is minimum.
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Step by step
- Find the thread: Pick the d x P row; fine pitch is always written with the pitch, e.g. M12 x 1.5.
- Pick the spanner: Use s for the wrench size; it matches the coarse ISO 4017 screw of the same diameter.
- Match the nut: Use a fine-thread nut with the same pitch, e.g. ISO 8673.
- Check the head: Use k and e for clearance in counterbores and socket reach.
ISO 8676 fine thread hex head screw dimensions (mm)
Columns: thread d x P, pitch P, width across flats s, head height k nom., width across corners e min.
- Size | P | s | k | e
- M8 x 1 | 1 | 13 | 5.3 | 14.38
- M10 x 1 | 1 | 16 | 6.4 | —
- M12 x 1.5 | 1.5 | 18 | 7.5 | —
- M16 x 1.5 | 1.5 | 24 | 10 | 26.75
- M20 x 1.5 | 1.5 | 30 | 12.5 | 33.53
- M24 x 2 | 2 | 36 | 15 | 39.98
- M30 x 2 | 2 | 46 | 18.7 | 50.85
Worked example: M12 x 1.5 adjuster
An M12 x 1.5 ISO 8676 screw takes an 18 mm spanner and has a 7.5 mm head. Each turn moves it 1.5 mm, versus 1.75 mm for coarse M12. Pair it with an M12 x 1.5 fine-thread nut.
Common problems
- Nut will not start: coarse nut on a fine screw; check the pitch in the designation.
- Cross-threading or galling: fine threads need clean, careful starts, especially in stainless.
- Spanner does not fit: old DIN 961 M10/M12 screws use 17 and 19 mm flats.
FAQ
Fine vs coarse pitch?
ISO 8676 has the same head as ISO 4017 but a finer thread: better for fine adjustment and thin walls, but more prone to cross-threading and galling. ISO 4017 coarse is the first choice.
ISO 8676 vs ISO 8765?
ISO 8676 is threaded to the head (like ISO 4017); ISO 8765 is the partly threaded fine pitch bolt (like ISO 4014).
Is DIN 961 the same?
ISO 8676 replaced DIN 961. DIN 961 uses larger flats at M10, M12, M14 and M22 (17, 19, 22, 32 mm), so old stock may need a different spanner.
Why is e dashed for M10 and M12?
One source lists the DIN 17 and 19 mm across-corner values; the ISO 16 and 18 mm flats give a different e, so the cell is left blank.
Related guides and calculators
- Fine thread hex bolts (ISO 8765)
- Hex head bolts (ISO 4014)
- Hex head screws (ISO 4017)
- Fine thread hex nuts (ISO 8673)
- All free machinist calculators
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