Choosing the right 4 inch cotter pin means balancing ease of use, durability, and compatibility with common hole sizes. This guide highlights five widely available options that perform well in automotive, trailer, and equipment applications. Each product is evaluated on material, length, prong design, and ease of insertion or removal to help you select the best fit for your project.
| Product | Brand | Length | Material | Profile |
|---|---|---|---|---|
| Hillman 381820 1/4 x 4-Inch Cotter Pin Extended Prong | Hillman | 4 inches | Metallics | Extended prong, easy insertion |
| Chipmunk Hardware 1/4 x 4 Inch Cotter Pins (Pack of 5) | Chipmunk Hardware | 4 inches | Zinc plated steel | Square cut, extended prong |
| uxcell 2Pcs 5/16″ x 4″ Single Hole Clevis Pins | uxcell | 4 inches | 304 stainless steel | Single-hole with through hole |
| Yoliko 2 Pcs Heavy Duty Stainless Steel Cotter Pin R Clip | Yoliko | 4 inches | 304 stainless steel | Hairpin/R clip design |
| Moicstiy 2Pcs M5x100 mm R Clips, 4 Inch Stainless Steel | Moicstiy | 4 inches | Stainless steel | Retaining cotter pins, versatile |
Summary: The five picks above cover common 4 inch cotter pins used across trailers, hand trucks, and machinery. They feature extended prongs or hairpin designs intended to secure components through holes, with materials ranging from zinc-plated steel to 304 stainless steel for corrosion resistance. The selection balances ease of installation, durability, and compatibility with standard hardware accessories.
Hillman 1/4 x 4-Inch Cotter Pin Extended Prong
The Hillman 381820 cotter pin provides a reliable securing method for two items through a common hole. The bulbous head helps prevent full passage through the hole, while the extended prong offers easier insertion and secure bending to lock in place. This 4-inch size is well-suited for automotive hardware, trailers, and equipment assemblies where standard cotter pins are used.
Chipmunk Hardware 1/4 x 4 Inch Cotter Pins (Pack of 5)
Chipmunk Hardware offers a compact 1/4 x 4 inch cotter pin in a pack of five with a zinc-plated steel finish. The square cut and extended prong design improve insertion control and hold, making it suitable for general fastening tasks in small to mid-size assemblies. This option is practical for hobbyist and professional work where standard cotter pins are required.
uxcell 2Pcs 5/16″ x 4″ Single Hole Clevis Pins
uxcell offers stainless steel 5/16 inch by 4 inch single-hole clevis pins. These 304 stainless steel pins provide good hardness and load-bearing capacity, with anti-corrosion properties suited for outdoor or rugged environments. The through-hole and flat head design deliver stable alignment, while compatibility with cotter pins or hairpins supports varied locking methods.
Yoliko 2 Pcs Heavy Duty Stainless Steel Cotter Pin R Clip
Yoliko’s large, heavy-duty stainless steel R clips are designed for trailer hitch pins and other high-stress applications. The 100 mm length with a 5 mm wire diameter offers robust holding power and high elasticity. The rust-resistant 304 stainless steel aids durability in outdoor or high-salinity environments, and the hairpin design ensures quick installation and removal when needed.
Moicstiy 2Pcs 5/16″ x 4″ Stainless Steel R Clips
Moicstiy provides two 4-inch stainless steel retaining cotter pins suitable for trailer pins and similar hardware. Made from stainless steel for rust resistance and wear resistance, these pins are designed for durable, long-term use across automotive and industrial contexts. The through-hole with hairpin-like retention supports secure locking and efficient installation.
Buying Guide: Key Considerations For 4 Inch Cotter Pins
When selecting a 4 inch cotter pin, consider material, prong design, hole compatibility, and environment. Stainless steel options deliver superior corrosion resistance for outdoor or maritime settings, while zinc-plated steel is cost-effective for indoor or dry environments. Extended prongs and hairpin/C-clip designs can improve insertion ease and retention in dynamic applications, but may require locking devices like cotter pins, split pins, or locking pins to prevent loosening. For trailer and heavy equipment, look for higher hardness and consistent diameter to resist deformation under load. Finally, ensure the pin length matches the hole depth and the gap between mounting parts to avoid excessive protrusion or pin failure.
Product diversity matters: 4 inch cotter pins come in several shapes—extended prong, square cut, and hairpin styles. Each design has unique advantages: extended prong for easier insertion, bulbous head stops over-travel, and hairpin clips for rapid installation and removal. Matching the pin to the fastened components (holes, bushings, or hitch pins) minimizes loosening risks and improves reliability over time.
Practical testing tips: check the fit by inserting the pin through the hole, then bend the prongs or secure with a complementary locking pin. Inspect for burrs or sharp edges that could wear through mating parts. When using stainless steel, confirm that the grade (e.g., 304) is appropriate for your environment, especially if exposure to salt or moisture is frequent. For budget-conscious projects, zinc-plated options offer reasonable performance, but consider upgrading to stainless steel where prolonged exposure is likely.
By choosing among these five options, you gain reliable 4 inch cotter pins suitable for standard high-use environments such as trailers, equipment assemblies, and home workshop projects. Ensure you verify hole size compatibility and the appropriate locking method to secure your connection effectively.