Cotter Pin Carbon Steel — Factory Direct Supplier | Huaxia-Steel
A carbon steel cotter pin (also called a split pin) is a simple, versatile fastener inserted through a hole in a shaft or bolt to secure a nut, castle nut, or component against rotation and axial movement. Despite its simplicity, the cotter pin is a critical safety component in machinery, automotive, agricultural, and structural applications where vibration and dynamic loads would otherwise loosen fasteners. Huaxia-Steel supplies carbon steel cotter pins manufactured to DIN 94, ISO 1234, and ASME B18.8.1 standards, available in a complete range of diameters (0.6mm to 25mm) and lengths with zinc-plated, black oxide, or plain finishes.
The cotter pin works by passing through a transverse hole and splitting its legs to lock the assembly. It is a low-cost, reusable (in non-critical applications), and universally recognized fastening solution. While stainless steel and brass cotter pins exist for corrosive environments, carbon steel cotter pins dominate general industrial use due to their strength and economy—especially when paired with protective surface treatments.
Product Overview
Carbon steel cotter pins from Huaxia-Steel are produced from low-carbon wire (Q235, 1008, or equivalent) formed into the characteristic split, semicircular cross-section shape with chamfered ends. The legs are slightly offset to create spring tension that holds the pin in place. Our pins are manufactured to tight dimensional tolerances and consistent hardness for reliable performance.
Specifications & Dimensions
Typical dimensions for DIN 94 carbon steel cotter pins:
| Nominal Dia (d) | Hole Dia (drill) | Head Height (c) | Length Range (l) | Wire Dia (d1) |
|---|---|---|---|---|
| 1.0 mm | 1.1 mm | 1.8 mm | 6–20 mm | 0.9 mm |
| 2.0 mm | 2.1 mm | 3.4 mm | 10–50 mm | 1.8 mm |
| 3.2 mm | 3.3 mm | 5.4 mm | 16–71 mm | 2.9 mm |
| 4.0 mm | 4.1 mm | 6.8 mm | 20–90 mm | 3.7 mm |
| 5.0 mm | 5.1 mm | 8.4 mm | 25–112 mm | 4.6 mm |
| 6.3 mm | 6.4 mm | 10.6 mm | 32–140 mm | 5.8 mm |
| 8.0 mm | 8.2 mm | 13.4 mm | 40–180 mm | 7.4 mm |
| 10.0 mm | 10.2 mm | 16.8 mm | 50–200 mm | 9.2 mm |
The status recommends selecting pin diameter approximately equal to 1/4 of the shaft diameter for optimal load distribution. Length should be chosen so the legs clear the component with room to bend.
Material Grades
| Grade | Standard | C (%) | Yield (MPa) | Application |
|---|---|---|---|---|
| Q235 / Q235A | GB/T 700 | 0.14–0.22 | 235 | General purpose, China market |
| 1008 / 1010 | ASTM A29 | 0.08–0.13 | 210 | General purpose, export |
| Low-carbon bright wire | EN 10270-1 | <0.15 | 200 | European, cold-drawn |
Carbon steel cotter pins are typically used in non-load-bearing safety locking roles. For load-bearing shear pins, higher-carbon grades (1045) may be specified—contact us for custom options.
Manufacturing Standards
Our carbon steel cotter pins conform to:
Note: ASME B18.8.1 cotter pins differ slightly from DIN 94—they have a tapered body (larger at head) rather than uniform diameter. Verify which standard your application requires.
Surface Treatments & Finishes
| Finish | Corrosion Resistance | Appearance | Best For |
|---|---|---|---|
| Plain (oil dipped) | Low | Black/dark steel | Indoor, dry environments |
| Zinc plated (electro) | Medium (72–96h salt spray) | Shiny silver | General outdoor, automotive |
| Black oxide | Low-Medium | Matte black | Tool, machinery (cosmetic) |
| Hot-dip galvanized | High (480h+ salt spray) | Dull gray | Harsh outdoor, marine-adjacent |
| Dacromet | Very High (500h+) | Silver-blue | High-corrosion, automotive |
How to Specify a Cotter Pin
- Determine pin diameter (d) — matches the hole drilled in the shaft or bolt
- Select length (l) — long enough for legs to bend back against the component
- Choose standard — DIN 94 (uniform) vs ASME (tapered)
- Pick finish — based on corrosion environment
- Confirm quantity — pins are low-cost; buy in bulk for savings
Applications
Carbon steel cotter pins are used across industries:
- Automotive & heavy equipment — securing castle nuts on axles, suspension, steering
- Agricultural machinery — PTO shafts, hitch pins, implement linkages
- Industrial machinery — securing rotating shafts, linkages, clevis pins
- Construction equipment — hydraulic cylinder rod ends, pivot joints
- Aerospace (non-critical) — secondary locking where weight is less critical
- Marine (galvanized) — rigging, tiller connections
- Railway — bogie and coupling safety locking
Installation Best Practices
- Insert pin through the hole with the head seated against the surface
- Spread the legs 180° apart on opposite sides of the shaft
- Bend legs back flat against the component—do not over-bend (causes cracking)
- For reuse, only in non-safety-critical applications; replace if deformed
- Never use a cotter pin as a primary load-bearing fastener
- Ensure the pin diameter matches the hole—loose pins rattle and fail
Quality Assurance
Our cotter pins are produced under controlled conditions:
Packaging & Shipping
- Bulk in cartons (small sizes: 1000–5000 pcs/box)
- Plastic bags with silica gel for moisture protection
- Weight-based or count-based packaging per customer request
- Seaworthy export cartons with palletization option
- Lead time: 10–20 days for standard sizes; custom sizes 20–30 days
We ship worldwide under FOB, CIF, CFR, DAP terms with full commercial documentation.
Why Choose Huaxia-Steel
- Factory-direct pricing on bulk cotter pins
- Full DIN 94 / ISO 1234 / ASME range in stock
- Multiple finishes: zinc, black oxide, HDG, Dacromet
- Consistent quality with dimensional certification
- MOQ from 10,000 pcs; mixed-size boxes available
- Fast global shipping with export documentation
Get a quote on carbon steel cotter pins. Contact Huaxia-Steel with your required diameter, length, standard, finish, and quantity. We respond within 24 hours with a competitive bulk offer and samples on request.
