Metric coarse thread is the default choice in many industrial fastener orders. In the workshop, we see it every day on bolts, screws, nuts, studs, anchors, and threaded rods. It is easy to source, easy to assemble, and usually more tolerant of dirt or minor handling damage than fine thread.

Still, buyers should not write only “M12 bolt” on an RFQ. The pitch must be confirmed, especially when parts must match existing nuts, tapped holes, or imported equipment.

What Metric Coarse Thread Means

Metric thread is described by diameter and pitch. For example, M12 × 1.75 means a 12 mm nominal diameter and a 1.75 mm pitch.

When the pitch is not written, many suppliers assume standard coarse pitch. That works for common stock items, but it can create mistakes when the mating part uses fine thread.

For regular orders, buyers can review common standard fasteners or bolt products before confirming the RFQ.

Common Metric Coarse Thread Chart

This chart is useful for quoting and quick checking, but final production should still follow the required DIN, ISO, ASTM, EN, or drawing standard.

Coarse Thread vs Fine Thread

When Coarse Thread Works Best

Coarse thread is usually preferred for:

• General industrial assembly
• Stock fastener supply
• Construction and maintenance work
• Parts exposed to dust or light corrosion
• Fast installation and field repair

Fine thread may be used when the design needs finer adjustment, thinner wall engagement, or specific OEM requirements. It should be clearly stated on the drawing or RFQ.

Common Buyer Mistakes

The most common mistake is mixing coarse and fine thread parts in one order. M12 × 1.75 and M12 × 1.5 look close, but they will not assemble correctly.

Also check coating. Hot-dip galvanizing, zinc flake, and PTFE coating can affect thread fit. For coated products, review various coated fasteners and confirm nut assembly after finishing.

RFQ Checklist

Before ordering metric coarse thread fasteners, provide:

1. Diameter and length
2. Coarse pitch value
3. Product standard
4. Material and strength grade
5. Surface finish
6. Matching nut or tapped hole requirement
7. Quantity and packaging

For unusual thread length, special pitch, or drawing-based parts, use custom non-standard fasteners.

Final Advice

Metric coarse thread is the safest starting point for many industrial fastener orders. But buyers should still confirm pitch, standard, material, grade, coating, and matching parts before production.

A clear thread specification prevents wrong-thread delivery, assembly delays, and unnecessary inspection disputes.