Cotter pins are made from which two materials?

Cotter pins are made from which two materials?

• A. Low-carbon steel and corrosion-resistant steel.
• B. Stainless steel and aluminum.
• C. Plastic and nylon.
• D. Titanium and brass.

Answer: (B)

Cotter pins need to be easy to form into a split pin and resist corrosion in aviation environments. Stainless steel provides strong shear strength and excellent corrosion resistance, making it a common choice. Aluminum is chosen for its light weight and good corrosion resistance, which is important when weight matters but the loads aren’t extreme. Plastic or nylon pins wouldn’t hold up well under typical aircraft conditions, and titanium or brass aren’t the usual pairing for cotter pins. So the two materials you’ll commonly see for cotter pins are stainless steel and aluminum.

Cotter pins need to be easy to form into a split pin and resist corrosion in aviation environments. Stainless steel provides strong shear strength and excellent corrosion resistance, making it a common choice. Aluminum is chosen for its light weight and good corrosion resistance, which is important when weight matters but the loads aren’t extreme. Plastic or nylon pins wouldn’t hold up well under typical aircraft conditions, and titanium or brass aren’t the usual pairing for cotter pins. So the two materials you’ll commonly see for cotter pins are stainless steel and aluminum.