ISO 4014 specifies the dimensions and tolerances for slotted hex bolt. The full dimensional table is reproduced below, followed by the DIN, ISO and ASME parts that match or supersede it.
- Standard
- ISO 4014
- Product
- Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005)
- Governing standards
- GB/T 5782 / ISO 4014
Equivalence between national standards is dimensional, not always metallurgical. Check the property class separately when substituting.
ISO 4014 covers the dimensional requirements for slotted hex bolt. Reproduced below: the complete size table, and the companion and equivalent standards referenced when ordering to this document.
ISO 4014 — Scope
ISO 4014 is "Fasteners — Hexagon head bolts — Product grades A and B". It covers M1.6 to M64. Partly threaded. The fully threaded equivalent is ISO 4017.
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
ISO 4014 defines product grades A and B. The grade sets how closely the finished part has to follow the nominal dimensions; it is not a strength rating.
Dimensions Specified by 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) |
|---|
| M3 | 0.5 | 3 | 20 | 5.5 | 6.01 | 2.0 |
| M4 | 0.7 | 4 | 25 | 7.0 | 7.66 | 2.8 |
| M5 | 0.8 | 5 | 30 | 8.0 | 8.79 | 3.5 |
| M6 | 1.0 | 6 | 40 | 10.0 | 11.05 | 4.0 |
| M8 | 1.25 | 8 | 50 | 13.0 | 14.38 | 5.3 |
| M10 | 1.5 | 10 | 60 | 16.0 | 17.77 | 6.4 |
| M12 | 1.75 | 12 | 80 | 18.0 | 20.03 | 7.5 |
| M14 | 2.0 | 14 | 80 | 21.0 | 23.36 | 8.8 |
| M16 | 2.0 | 16 | 100 | 24.0 | 26.75 | 10.0 |
| M18 | 2.5 | 18 | 100 | 27.0 | 30.14 | 11.5 |
| M20 | 2.5 | 20 | 120 | 30.0 | 33.53 | 12.5 |
| M24 | 3.0 | 24 | 150 | 36.0 | 39.98 | 15.0 |
| M30 | 3.5 | 30 | 180 | 46.0 | 50.85 | 18.7 |
| M36 | 4.0 | 36 | 200 | 55.0 | 60.79 | 22.5 |
Equivalent Standards
ISO 4014 (partial thread) corresponds closely to DIN 931; the fully-threaded variant ISO 4017 corresponds to DIN 933.
When to Specify ISO 4014
Choose ISO 4014 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for slotted hex bolt — gb/t 5782 / iso 4014 (series 005).
Custom manufacturing · Made to drawing
Need a bolt to this standard in a non-standard size?
Parts built to ISO 4014 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom bolt manufacturingSend a drawing
Applications & Industries
What Slotted Hex Bolt are specified for, industry by industry. Stocked from M3 to M36.
Industries that specify Slotted Hex Bolt
-
Machine building & OEM
The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.
-
Automotive & transport
Chassis, driveline and body fixings that see vibration and are assembled to a controlled preload.
-
Steel fabrication
Bolted connections in frames, enclosures, walkways and weldments, on the bench and on site.
-
Energy & infrastructure
Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
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Maintenance & MRO
Stocked replacements matched to an existing property class, thread and finish.
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Food, pharma & cleanroom
Stainless assemblies that are washed down, where the finish matters as much as the strength.
Typical applications
- assemblies that are dismantled for service and re-torqued
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
- bolting brackets, motors and gearboxes to a frame
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Full application guide: where Slotted Hex Bolt are used, how to specify them, and the cases they are wrong for
