This M39 bolt reference summarizes the identifying details associated with BS 3692, including the metric thread designation, coarse-pitch information, hexagonal head form, and listed material options. Use the source data below when checking a bolt description against fabrication, procurement, or detailing requirements.
For related work, compare this reference with guidance on metric bolt dimensions, thread pitch, property classes, and steel connection detailing. The accompanying DWG resource can also support CAD-based review, but the drawing should be checked against the project specification before use.
Standard: BS 3692 (British Standard for precision hexagon bolts, screws, and nuts)
Thread Size: M39 (Metric thread, 39 mm nominal diameter)
Thread Pitch (Coarse): 4.0 mm (fine pitch options like M39×3.0 are available)
Thread Type: ISO metric, 60° thread angle
Bolt Types Covered: Hex bolts, hex screws, and set screws
Material Grades: Typically available in property classes 8.8, 10.9, or stainless steel
Tolerances: External thread tolerance 6g (standard metric fit)
Head Type: Hexagonal (per BS 3692 dimensional specs)
Applications: Mechanical and structural engineering, marine, oil & gas, heavy machinery, infrastructure
How to read the M39 designation
The M39 designation identifies an ISO metric thread with a nominal diameter of 39 mm. The listed coarse thread pitch is 4.0 mm, while the source also identifies M39×3.0 as a fine-pitch option. Thread pitch is important when matching the bolt with a compatible nut and when checking clearances, engagement, and detailing requirements.
What BS 3692 covers in this reference
The source describes BS 3692 in relation to precision hexagon bolts, screws, and nuts. It identifies hex bolts, hex screws, and set screws, with a hexagonal head form and an external thread tolerance of 6g. These descriptors help distinguish the fastener configuration from other metric fastener types and support clearer specification review.
Material and application checks
The listed material choices include property classes 8.8 and 10.9, along with stainless steel. These designations should not be treated as interchangeable: confirm the required property class, material, corrosion environment, tightening method, and connection requirements in the governing project documents. Applications listed in the source include mechanical and structural engineering, marine, oil and gas, heavy machinery, and infrastructure.
Using the DWG reference
The downloadable DWG file provides a CAD reference for an M39 bolt, nut, and hex head with full threading. Review the drawing together with the BS 3692 requirements and project-specific connection details; do not rely on a CAD file alone to establish suitability for a designed connection.
Frequently asked questions
What does M39 mean?
M39 identifies an ISO metric thread with a nominal diameter of 39 mm.
What is the coarse pitch listed for an M39 bolt?
The source lists a coarse thread pitch of 4.0 mm and also identifies M39×3.0 as a fine-pitch option.
What thread tolerance is listed?
The listed external thread tolerance is 6g, described as the standard metric fit in the source reference.
Which material grades are identified?
The reference lists property classes 8.8 and 10.9, as well as stainless steel. Confirm the required material and property class against the project specification.
What head form is associated with this reference?
The source identifies a hexagonal head and covers hex bolts, hex screws, and set screws.
Is a CAD file available?
Yes. The page includes a DWG download for an M39 bolt, nut, and hex head with full threading. Check the file against the applicable requirements before incorporating it into design or fabrication documents.
