The M14 size of Hex Bolt is dimensioned by GB/T 5783 / ISO 4017. The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.
M14 Dimensional Row (GB/T 5783 / ISO 4017)
| Size | Pitch (mm) | Nominal diameter d (mm) | Length L (mm) | Width across flats s (mm) | Width across corners e (mm) | Head height k (mm) |
|---|---|---|---|---|---|---|
| M14 | 2.0 | 14 | 80 | 21.0 | 23.36 | 8.8 |
Spanner & Drive for M14 Hex Bolt — GB/T 5783 / ISO 4017 (Series 010)
M14 Hex Bolt — GB/T 5783 / ISO 4017 (Series 010) have a width across flats of 21.0 mm — fit a 21.0 mm open-ended spanner or socket. A 6-point socket grips all six flats of the 21.0 mm hex and is what to reach for once a fastener has been on and off a few times; a 12-point ring spanner starts rounding a worn head. For repeatable preload, torque rather than feel.
Hole Sizes for M14
| Coarse-thread pitch (ISO 724) | 2 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 15.5 mm |
| Tapping drill, coarse thread | 12 mm |
Tightening Torque for M14
| Class 8.8 (dry, ~µ 0.125) | ≈ 134 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 197 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 231 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M14
| Tensile stress area As (ISO 724) | 115 mm² |
|---|---|
| Proof load, class 8.8 | 67 kN |
| Proof load, class 10.9 | 96 kN |
| Proof load, class 12.9 | 112 kN |
| Min. ultimate tensile load, class 8.8 | 92 kN |
Proof load = tensile stress area × the proof stress Sp of the class, per ISO 898-1 — Sp is a lower figure than the yield stress Rp0.2 and the two are not interchangeable. The stress area is computed from this size's own diameter and pitch, so a fine-pitch designation gives the fine-pitch figure. Design the joint so the working preload stays below the proof load of the class selected.
M14 Hex Bolt — GB/T 5783 / ISO 4017 (Series 010) Weight
A steel M14 hex bolt at the listed 80 mm length weighs approximately 123 g each — about 123 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³).
Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Installation Tips for M14 Hex Bolt — GB/T 5783 / ISO 4017 (Series 010)
- 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
For M14, pair with a M14 hex nut (ISO 4032 / DIN 934) and, where used, a M14 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need hex bolt in a size this table does not list?
This page covers M14 hex bolt. Head form and drive can be specified to the assembly rather than to a standard: a larger bearing face, a security drive, or a socket sized for the tool already on the bench. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
