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Spherical Seat Hex Nut Dimensions (DIN 6330 Form B, M6 to M48)
Guide · Updated October 28, 2026
DIN 6330 covers form B hex nuts with a one-sided spherical seat, height m = 1.5 x d, M6 to M48. Values agree across Aspen Fasteners, Torqbolt, Ganter and OPAC tables (Ganter lists M8 to M36). e is minimum.
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Step by step
- Find the thread: Pick the row for your stud, M6 to M48.
- Pick the spanner: Use s for the wrench size, e.g. 18 mm for M12.
- Check the height: m is 1.5 x d, e.g. 18 mm for M12; allow it in the stud length.
- Match the seat: Use the spherical end against a DIN 6319 conical seat of the same size; r is the seat radius.
DIN 6330 spherical seat hex nut dimensions (mm)
Columns: thread d, spherical seat diameter d1, width across flats s, width across corners e min, height m, sphere radius r.
- Size | d1 | s | e min | m | r
- M6 | 7 | 10 | 11.05 | 9 | 9
- M8 | 9 | 13 | 14.38 | 12 | 11
- M10 | 11.5 | 16 | 17.77 | 15 | 15
- M12 | 14 | 18 | 20.03 | 18 | 17
- M16 | 18 | 24 | 26.75 | 24 | 22
- M20 | 22 | 30 | 33.53 | 30 | 27
- M24 | 26 | 36 | 39.98 | 36 | 32
- M30 | 32 | 46 | 51.28 | 45 | 41
- M36 | 38 | 55 | 61.31 | 54 | 50
- M42 | 44 | 65 | — | 63 | 58
- M48 | 52 | 75 | 83.91 | 72 | 67
Worked example: M12 nut
An M12 DIN 6330 nut takes an 18 mm spanner, is 18 mm tall and has a 17 mm sphere radius on a 14 mm seat diameter. Pair it with an M12 DIN 6319 form D seat.
Common problems
- Stud too short: the nut is 1.5 x d tall; check m.
- Nut on upside down: the spherical end must face the conical seat.
- Mismatched seat: use the same size DIN 6319 seat so the radii match.
FAQ
What is DIN 6330 used for?
Clamping that is tightened and released often; the spherical end with a DIN 6319 seat takes up misalignment.
How is it different from an ISO 4032 nut?
It is 1.5 x d tall (18 mm for M12) and has a spherical end with radius r.
Do I still need a spherical washer?
No; the nut replaces the form C washer. Use it with the form D or G conical seat.
Why is M42 e min a dash?
Sources give 72.61 mm and 76.2 mm, so the cell is left blank.
Related guides and calculators
- Spherical washers (DIN 6319)
- Clamping washers (DIN 6340)
- Collar nuts (DIN 6331)
- All free machinist calculators
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