Key specifications
| Sizes | M5, M6, M8, M10, M12, M16, M20; inch 1/4 to 3/4 in |
|---|---|
| Lengths | About 16 mm to 300 mm |
| Grades | 4.6, 8.8; stainless A2-70 or A4-70 |
| Finishes | Zinc plated, hot-dip galvanized, plain stainless |
| Matching nut | DIN 934 / ISO 4032 or DIN 555 hex nut, DIN 125 / DIN 9021 washer |
| Uses | Timber construction, fencing, playgrounds, trailers, racking |
Made to order in China and shipped FOB or CIF from Tianjin, Ningbo, Shanghai or Shenzhen. Sizes, grades and finishes outside this list can be quoted.
Dimension drawing
DIN 603 dimensions (mm)
Head diameter dk and head height k are nominal values. The square neck is about the thread diameter across flats. Thread length b follows the same rule as DIN 931.
| Size | Head Ø dk | Head height k | Square width v max | b (L ≤ 125) | b (125 < L ≤ 200) | Inquiry |
|---|---|---|---|---|---|---|
| M5 | 13 | 3 | 5.48 | 16 | 22 | Quote this size |
| M6 | 16 | 3.5 | 6.48 | 18 | 24 | Quote this size |
| M8 | 20 | 4.5 | 8.58 | 22 | 28 | Quote this size |
| M10 | 24 | 5 | 10.58 | 26 | 32 | Quote this size |
| M12 | 30 | 6.5 | 12.7 | 30 | 36 | Quote this size |
| M16 | 38 | 8.5 | — | 38 | 44 | Quote this size |
| M20 | 46 | 10.5 | 20.84 | 46 | 52 | Quote this size |
Choosing grade and finish
- Grade 4.6 zinc plated or hot-dip galvanized is the usual choice for timber and fencing.
- Grade 8.8 for trailers, racking and steel-to-steel joints with square holes.
- Hot-dip galvanized bolts need galvanized nuts tapped oversize; order them as a set.
- Stainless A2 or A4 for treated timber, coastal and playground use, where galvanizing may react with timber preservatives.
Packing, shipping and documents
| MOQ | 500 pcs per specification; mixed sizes can be combined on one order |
|---|---|
| Lead time | 10–15 days for stock items, 25–30 days for production orders, confirmed in the quotation |
| Export packing | Inner boxes or bags labelled by size, export cartons, then palletized and stretch-wrapped; buyer labels and barcodes on request |
| Shipping ports | Tianjin, Ningbo, Shanghai, Shenzhen |
| Incoterms | EXW, FOB, CFR, CIF, DAP, DDP on request |
| HS code reference | HS 7318.15 (other threaded screws and bolts) is the usual heading for U-bolts, carriage bolts and threaded eye bolts. Confirm the final code with your customs broker. |
| Certificate of origin | ACFTA Form E available on request for buyers in ASEAN countries such as Malaysia, Indonesia, Vietnam and the Philippines |
| Order documents | Commercial invoice, packing list and inspection records agreed in the quotation |
What to include in your RFQ
- Size × length, e.g. M10 × 100
- Grade and finish
- Nuts and washers per bolt
- Inch (ASME B18.5) or metric (DIN 603)
- Quantity per size, packing, destination
Frequently asked questions
What is a carriage bolt used for?
Fixing timber to timber or timber to steel where a smooth, tamper-resistant head is wanted. The square neck stops the bolt turning while the nut is tightened.
What is the head diameter of an M10 carriage bolt?
About 24 mm for DIN 603, with a 5 mm head height.
Do carriage bolts need a square hole?
In timber, the square neck cuts its own seat when the nut is tightened. In steel, punch or cut a square hole the size of the neck.
What is the MOQ for carriage bolts?
Reference MOQ is 500 pcs per specification. This product is made to order, so lead time and price are confirmed with each quotation. We reply to every RFQ within 2 working hours.
Sources for technical review