At Ananka Fasteners Pvt Ltd, we manufacture fasteners to the dimensional requirements of ASME B18.2.3.1M. ASME B18.2.3.1M establishes the general and dimensional requirements for metric series hex cap screws (finished hex bolts with a washer face) recognized as an American National Standard. It governs head geometry — width across flats, width across corners and head height — plus thread length and body diameter. The standard covers nominal sizes from M5 through M100.
ASME B18.2.3.1M establishes the general and dimensional requirements for metric series hex cap screws (finished hex bolts with a washer face) recognized as an American National Standard. It governs head geometry — width across flats, width across corners and head height — plus thread length and body diameter. The standard covers nominal sizes from M5 through M100.
A finished hex-head cap screw with a machined washer face under the head and a chamfered point, produced to closer tolerances than a common hex bolt for use as a bolt or screw in tapped or clearance holes.
Key dimensions for common sizes are listed below.
| Nominal Size | Width Across Flats (mm) | Width Across Corners (mm) | Head Height (mm) |
|---|---|---|---|
| M5 | 8 | 9.24 | 3.65 |
| M6 | 10 | 11.55 | 4.15 |
| M8 | 13 | 15.01 | 5.50 |
| M10 | 16 | 18.48 | 6.63 |
| M12 | 18 | 20.78 | 7.76 |
| M16 | 24 | 27.71 | 10.32 |
| M20 | 30 | 34.64 | 12.88 |
| M24 | 36 | 41.57 | 15.44 |
| M30 | 46 | 53.12 | 19.48 |
| M36 | 55 | 63.51 | 23.38 |
| M42 | 65 | 75.06 | 26.97 |
| M48 | 75 | 86.60 | 31.07 |
Metric coarse threads per ASME B1.13M, external thread tolerance class 6g.
Companion to ASME B18.2.3.5M (metric hex bolts) and B18.2.3.3M (metric heavy hex screws); the metric counterpart of inch ASME B18.2.1 hex cap screws and broadly equivalent to ISO 4014/4017 and DIN 931/933.
For the official ASME standards catalogue, see the ASME standards listing. This external reference is provided for standards identification; the purchaser should verify the current edition applicable to the order.
We produce ASME B18.2.3.1M fasteners in carbon and alloy steel, austenitic, duplex and super-duplex stainless, and high-nickel, titanium and copper alloys — for structural, flanged, machinery and process applications worldwide.
For technical documentation and quotations, buyers can also review the Ananka Fasteners manufacturing and supply range or contact the team through the fastener enquiry and technical support page.
Ananka Fasteners supplies every lot with full material traceability and third-party testing on request.
ASME B18.2.3.1M establishes the general and dimensional requirements for metric series hex cap screws (finished hex bolts with a washer face) recognized as an American National Standard. It governs head geometry — width across flats, width across corners and head height — plus thread length and body diameter. The standard covers nominal sizes from M5 through M100.
Ananka Fasteners manufactures ASME B18.2.3.1M in sizes from M5–M48. See the Dimensional Table above for the complete size breakdown.
Metric coarse threads per ASME B1.13M, external thread tolerance class 6g.
We produce ASME B18.2.3.1M fasteners in carbon and alloy steel, austenitic, duplex and super-duplex stainless, and high-nickel, titanium and copper alloys — for structural, flanged, machinery and process applications worldwide.
Yes. For a quotation, provide the required nominal size, material grade, quantity and any inspection or certificate requirements.
Need a fastener manufactured to ASME B18.2.3.1M for an industrial project? Send the required fastener type, size, material grade, quantity and certification requirements to Ananka Fasteners. Our team can review the requirement and provide technical and commercial information for standard or custom configurations.
Recommended RFQ details: ASME B18.2.3.1M requirement, nominal size, material grade, quantity, inspection requirements and EN 10204 certificate requirements where applicable.
Dimensions compiled per ASME B18.2.3.1M and industry references; provided for reference only — confirm against the current edition of the standard before design use.
