Family · Bolts

Hex bolts and structural bolts, M6 – M30.

Bolts in this family are cold-headed to DIN 931/933, ISO 4014/4017 and ANSI/ASME B18.2.1 in classes 4.8 to 12.9 and A2/A4 stainless. Full thread or partial thread, zinc, hot-dip galvanized or zinc flake — with the MOQ and price breaks stated before you ask.

5 SKUs published

MOQ 5,000

DIN 933 · ISO 4017

Hex Head Bolt

Fully threaded hex bolt, property class 8.8 as standard, M6 to M30. The workhorse fastener for steel structures, machinery frames and general assembly.

From $0.061/pc at 100,000 pcs

Specs

MOQ 5,000

DIN 931 · ISO 4014

Hex Head Bolt

Partially threaded hex bolt for shear-critical joints where an unthreaded shank must bear the load.

From $0.066/pc at 100,000 pcs

Specs

MOQ 4,000

DIN 603

Carriage Bolt

Domed-head carriage bolt with a square neck that locks into timber and stops the bolt from turning.

From $0.14/pc at 80,000 pcs

Specs

MOQ 1,000

DIN 580

Forged Eye Bolt

Forged lifting eye bolt with a seamless eye and a stamped working load limit. M8 to M24.

From $0.41/pc at 20,000 pcs

Specs

MOQ 500

DIN 3570

U-Bolt

Bent U-bolt for pipe and tube clamping, with rolled thread on both legs and two nuts per piece.

From $0.64/pc at 10,000 pcs

Specs

Specify it once

What to put on the drawing or the PO.

The four lines below decide whether the parts fit, hold and survive. Nine quoting delays out of ten are one of them missing.

Full thread (DIN 933) or partial thread (DIN 931) — the thread must not sit in the shear plane of a structural joint.
Property class and whether the joint is preloaded: 8.8 is the default, 10.9 needs a controlled tightening method, 12.9 restricts coating choice.
Thread tolerance 6g external, and whether the mating nut is over-tapped for hot-dip galvanizing (EN ISO 10684).
Length convention — under-head for DIN/ISO, and the bolt length that actually clears the nut and washer stack.

Where it goes wrong

Mistakes we see on incoming drawings.

We will flag these before production rather than after the first inspection. If a mistake is already in the drawing, we say so in writing on the quote.

Substituting DIN 933 for DIN 931 on a connection designed for partial thread, which puts threads into the shear plane.
Electroplating class 10.9 or 12.9 without a hydrogen embrittlement bake, or specifying electroplate on 12.9 at all.
Forgetting that hot-dip galvanizing adds 45 – 85 µm: the nut has to be over-tapped or it will not run down.

Common questions

Bolts — answered before you ask.

Something not covered? Email matrixgrowth@foxmail.com and a person answers, usually inside a shift.

What is the difference between DIN 933 and DIN 931?

DIN 933 (ISO 4017) is fully threaded; DIN 931 (ISO 4014) is threaded for part of the shank so the unthreaded shank carries the shear load. They are not interchangeable on a joint designed for one or the other.

Can you supply class 12.9 with zinc plating?

Generally no, and we will argue against it. Electroplating at that strength traps hydrogen; most OEM specs (VW TL 845, GMW 3044, Toyota TSH 6605) restrict it. We quote 12.9 with black oxide or zinc flake instead.

Do you supply structural bolts to EN 14399?

We make the bolt and nut to the dimensional and property requirements and quote the assembly with washers. If your project requires a specific bolt-nut-washer lot to be tested together, say so at RFQ — that changes the packing and the test plan.

Other families

What else leaves the same plant.

Next step

Send the standard number and the quantity.

You get unit price, MOQ, pack multiple, lead time and the Incoterm you buy on — within one business day, with the HS code for your broker.

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