Reference illustration — produced to your drawing
Bolts
Carriage Bolts
A round-head bolt with a square neck directly under the head. The square neck seats into a square hole or bites into wood to stop the bolt rotating while the nut is tightened.
Common in timber structures, fences, gates, and light equipment. Bought by builders, fabricators, and agricultural equipment makers.
Standard
ASME B18.5 / DIN 603
Size range
M5 – M20 · 3/16 – 3/4 in
MOQ
From 50 pcs
Lead time
Samples 5–10 days
What we produce
- Carbon steel, stainless steel 304, or alloy steel 4140
- Domed head with square neck under the head
- Metric coarse, UNC, and UNF threads
- Zinc, hot-dip galvanized, or plain finish
- General tolerance to ISO 2768-m
- MOQ from 50 pieces
Specification notes
- Common lengths from 12 mm to 200 mm
- Pairs with a hex nut and flat washer
- Hot-dip galvanized option for outdoor timber
- Samples 5-10 days, production 25-35 days
Specifications
Every line below is a starting point, not a limit. Non-standard sizes, special threads and unusual materials are what we do — send the drawing and we confirm what fits.
| Standard | ASME B18.5 / DIN 603 |
|---|---|
| Size range | M5 – M20 · 3/16 – 3/4 in |
| Threads | Metric coarse · UNC · UNF |
| Head / geometry | Domed round head with a square neck under the head; no drive recess |
| Materials | Stainless steel 301 / 303 / 304 / 304L / 316 / 316L / 410 / 416 / 17-4PH · carbon steel 1045 / 1215 / 12L14 · alloy steel 4130 / 4140 · aluminium 2024 / 5052 / 6061 / 7075 · brass · bronze · copper · titanium |
| Finishes | As machined · black oxide · zinc plating · nickel plating · chrome plating · anodizing · passivation (through our vetted partner network) |
| Precision | ±0.01 mm on features that locate, seal or fit; ISO 2768-m for general dimensions |
| Marking | Head marking, grade marking or your own identification mark per drawing |
| Documents | Material certificate (MTR) with every batch, plus pre-shipment photos before dispatch |
| MOQ | From 50 pieces per type and material · samples from 1 piece |
| Sample lead time | 5–10 days |
| Production lead time | 25–35 days after sample approval |
| Quote | Within 24 hours, with DFM feedback |
Standard dimensions
Metric hex head bolts and screws — nominal dimensions (ISO 4014 / ISO 4017)
| d | Pitch (mm) | s (mm) | k (mm) | e (mm) |
|---|---|---|---|---|
| M5 | 0.8 | 8 | 3.5 | 8.79 |
| M6 | 1.0 | 10 | 4 | 11.05 |
| M8 | 1.25 | 13 | 5.3 | 14.38 |
| M10 | 1.5 | 16 | 6.4 | 17.77 |
| M12 | 1.75 | 18 | 7.5 | 20.03 |
| M16 | 2.0 | 24 | 10 | 26.75 |
| M20 | 2.5 | 30 | 12.5 | 33.53 |
| M24 | 3.0 | 36 | 15 | 39.98 |
| M30 | 3.5 | 46 | 18.7 | 50.85 |
| M36 | 4.0 | 55 | 22.5 | 60.79 |
d = nominal thread diameter · s = width across flats · k = head height · e = width across corners. Nominal values; your drawing always takes precedence.
Other bolts we manufacture
See all 179 part types →
Send us the drawing
We reply within 24 hours with DFM feedback, a process route and a price. Samples from 1 piece, production from 50 pieces, shipped from Qidong City, Jiangsu Province, China.
Request a quote