M5 is one of the standard coarse-thread sizes for slotted hex bolt under GB/T 5782 / ISO 4014. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.
M5 Dimensional Row (GB/T 5782 / ISO 4014)
| Size | Pitch (mm) | Nominal diameter d (mm) | Length L (mm) | Width across flats s (mm) | Width across corners e (mm) | Head height k (mm) |
|---|---|---|---|---|---|---|
| M5 | 0.8 | 5 | 30 | 8.0 | 8.79 | 3.5 |
Spanner & Drive for M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005)
M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005) have a width across flats of 8.0 mm — fit a 8.0 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.
Hole Sizes for M5
| Coarse-thread pitch (ISO 724) | 0.8 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 5.5 mm |
| Tapping drill, coarse thread | 4.2 mm |
Tightening Torque for M5
| Class 8.8 (dry, ~µ 0.125) | ≈ 5.8 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 8.1 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 9.7 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 M5
| Tensile stress area As (ISO 898-1) | 14.2 mm² |
|---|---|
| Proof load, class 8.8 | 8.2 kN |
| Proof load, class 10.9 | 11.8 kN |
| Proof load, class 12.9 | 13.8 kN |
| Min. ultimate tensile, class 8.8 | 11.4 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005) Weight
A steel M5 slotted hex bolt at the listed 30 mm length weighs approximately 6.1 g each — about 6.1 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.
Common Applications for M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005)
M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005) are commonly specified for precision instruments, small machinery and consumer-electronics enclosures.
Installation Tips for M5 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005)
- 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 M5 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
Mating Parts for M5
For M5, pair with a M5 hex nut (ISO 4032 / DIN 934) and, where used, a M5 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.