Decision Notes
What to confirm first.
- Use diameter, pitch, length, material, grade, finish, and standard together.
- M6, M8, M10, and M12 bolts can vary by DIN, ISO, and local supply practice.
- A complete RFQ gets faster and more accurate pricing than a short size-only request.
Buyer Guide
Metric bolt searches often start with a simple question: what size, pitch, head size, material, and standard should be written on the RFQ? This guide gives purchasing teams a fast reference before they ask for DIN 933, ISO 4017, stainless steel, carbon steel, or custom fastener quotes.
Quick metric bolt reference for common coarse threads: M6 usually uses 1.0 mm pitch and a 10 mm hex across flats size. M8 usually uses 1.25 mm pitch and a 13 mm hex across flats size. M10 usually uses 1.5 mm pitch, with 16 mm or 17 mm hex size depending on the standard and supply market. M12 usually uses 1.75 mm pitch, with 18 mm or 19 mm hex size depending on the standard. Always confirm the drawing or standard before purchasing.
DIN 933 and ISO 4017 are common fully threaded hex bolt references, but buyers should not compare price only by diameter. The same M10 bolt can require different length, material, grade, surface finish, packing, certificate, and inspection terms. These details affect price, lead time, and whether the supplier can ship the exact part.
For stainless steel fasteners, SS304 is common for general corrosion resistance, while SS316 is often selected for marine, chemical, outdoor, or higher-corrosion environments. For carbon steel fasteners, grade and finish should be confirmed together, because zinc plating, hot-dip galvanizing, black oxide, and plain finish are not interchangeable in real service conditions.
A clear RFQ for metric bolts should include diameter, length, thread pitch, thread type, standard, material, grade or property class, surface finish, quantity, application environment, packing method, destination country, Incoterms, and any certificate requirement such as material report or inspection document. If an equivalent standard is acceptable, state that clearly.
For export buyers, the biggest mistake is sending only a short line such as M10 bolt price. That is not enough for accurate sourcing. A better line is: hex head bolt DIN 933 or ISO 4017, M10 x 50, SS316, full thread, plain finish, 10,000 pcs, export carton packing, destination port required. This lets suppliers quote the same item instead of guessing.
If the project is urgent, share the acceptable substitute standards, target delivery window, and whether mixed sizes can be packed by SKU. This reduces back-and-forth and helps the supplier recommend stock, production, or alternative materials faster.
Savin Industry can support metric bolt RFQs with related washers, nuts, threaded rods, screws, and export packing notes. Buyers can start from this chart, then send the final drawing, quantity, and application for confirmation.
FAQ
Questions buyers usually ask next.
What is the common coarse thread pitch for M8, M10, and M12 bolts?
Common coarse thread pitch is usually M8 x 1.25, M10 x 1.5, and M12 x 1.75. Buyers should still confirm the drawing, standard, and whether fine thread is required.
Why do some M10 bolts use a 16 mm head and others use 17 mm?
Hex head size can vary by standard, market, or legacy drawing requirement. Confirm whether the RFQ follows DIN, ISO, or a project-specific drawing before comparing quotations.
What should I include when requesting a metric bolt quotation?
Include standard, diameter, length, pitch, material, grade or property class, finish, quantity, application, packing, destination, Incoterms, and certificate requirements.
Is SS304 or SS316 better for metric bolts?
SS304 is suitable for many general applications. SS316 is usually preferred for marine, chemical, outdoor, or higher-corrosion environments. The final choice should follow the application and drawing requirements.