The M39 size of Hex Nuts is dimensioned by ISO 4032 / ISO 4033. The table below gives the dimensional row from the standard, followed by the drive and the installation notes for this type.
M39 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 |
|---|---|---|---|---|---|---|
| M39 | 4.0 | 60.0 | 66.44 | 31.0 | 39.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M39 Hex Nuts
M39 Hex Nuts have a width across flats of 60.0 mm — fit a 60.0 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 M39 Hex Nuts
M39 Hex Nuts are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M39 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.
- At M39 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M39
Pair M39 with the matching M39 bolt or screw, plus a M39 flat washer where required to distribute load on softer materials.
