M14 is one of the standard coarse-thread sizes for hex nuts under ISO 4032 / ISO 4033. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.
M14 Dimensional Row (ISO 4032 / ISO 4033)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m style 1 (mm) | Nut height m style 2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M14 | 2.0 | 21.0 | 23.36 | 11.0 | 14.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M14 Hex Nuts
M14 Hex Nuts have a width across flats of 21.0 mm — fit a 21.0 mm open-ended spanner or socket. Use a 6-point socket for tight clearances and to reduce rounding; for repeated assembly choose a torque wrench so the joint preload is repeatable.
Common Applications for M14 Hex Nuts
M14 Hex Nuts are commonly specified for medium-duty structural joints and motor / chassis mounting.
Installation Tips for M14 Hex Nuts
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- On flanged or serrated variants, do NOT add a separate flat washer — the flange already spreads the load and the washer can defeat the locking serrations.
Mating Parts for M14
Pair M14 with the matching M14 bolt or screw, plus a M14 flat washer where required to distribute load on softer materials.

