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HV Structural Nut Dimensions (DIN 6915, M12 to M36)
Guide · Updated October 28, 2026
DIN 6915 covers class 10 HV structural hex nuts with large width across flats, M12 to M36, now replaced by EN 14399-4. Pitch, width across flats, width across corners and nut height agree across the fasteners.eu DIN 6915 table, the Ferrobolt DIN 6915 chart, the MF Industries DIN 6915 sheet and the Wegertseder sheet (M12 to M30); bearing face dw min matches fasteners.eu and MF Industries. Skipped: minimum tolerances and weights. Check your supplier for critical work.
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Step by step
- Pick the size: Match the DIN 6914 HV bolt, M12 to M36.
- Pick the wrench: Width across flats s matches the bolt head, e.g. 32 mm at M20.
- Check nut height: Nut height m is the nominal maximum.
- Check the bearing face: Bearing face dw min tells you the minimum contact circle on the washer.
- Build the set: Use with DIN 6914 bolts and DIN 6916 washers, one washer under the nut.
- Check projection: Leave at least a couple of threads past the nut.
DIN 6915 HV nut dimensions (mm)
Columns: thread, pitch P, width across flats s, width across corners e min, nut height m, bearing face dw min.
- Thread | P | s | e min | m | dw min
- M12 | 1.75 | 22 | 23.91 | 10 | 20
- M16 | 2 | 27 | 29.56 | 13 | 25
- M20 | 2.5 | 32 | 35.03 | 16 | 30
- M22 | 2.5 | 36 | 39.55 | 18 | 34
- M24 | 3 | 41 | 45.2 | 19 | 39
- M27 | 3 | 46 | 50.85 | 22 | 43.5
- M30 | 3.5 | 50 | 55.37 | 24 | 47.5
- M36 | 4 | 60 | 66.44 | 29 | 57
Worked example: M20 HV set
An M20 DIN 6915 nut is 16 mm tall with a 32 mm wrench size, the same as the DIN 6914 head. Add 16 mm nut plus 4 mm DIN 6916 washer plus projection to the grip for bolt length.
Common problems
- Wrong wrench: HV nuts are one size larger than ISO 4032 nuts.
- Galling during tightening: check lubrication on galvanized sets.
- Mixed sets: keep bolt, nut and washer from the same HV set.
FAQ
What is DIN 6915?
A class 10 hex nut with large width across flats for high-strength preloaded (HV) steel joints, used with DIN 6914 bolts and DIN 6916 washers.
What is the EN or ISO equivalent?
EN 14399-4 (HV system) replaced DIN 6915. One database lists ISO 4775 as equivalent but notes that is not verified, so check EN 14399-4 for new work.
Same wrench as the bolt?
Yes. DIN 6915 nuts and DIN 6914 heads share the same width across flats.
What was skipped?
Height and width-across-flats minimums and the minimum wrenching height (one source differs at M16 and M24), plus weights.
Can I use a regular nut?
No. HV joints need the matched class 10 HV nut.
Related guides and calculators
- HV structural bolt dimensions (DIN 6914)
- HV structural washer dimensions (DIN 6916 / ISO 7416)
- Heavy-duty washer dimensions (DIN 7989)
- All free machinist calculators
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