COTTER PINS

Product Specification :
A Cotter Pin, also known as a split pin, is a simple metal fastener with two tines that are bent during installation. It is used to secure bolts, pins, or shafts in place, typically acting as a safety locking device to prevent a nut from backing off a threaded fastener (especially when used with a castle nut or slotted nut).
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1. General Characteristics
Design: A half-round wire folded in half to form a loop (eye) at one end.
Function: Inserted into a pre-drilled hole; the two protruding ends (tines) are then spread apart to lock the pin in position.
Point Styles:
Chisel Point: Standard angled ends for easy spreading.
Extended Prong: One tine is longer than the other to make it easier to separate them with pliers.
Hammer Lock: Designed so that a strike from a hammer automatically spreads the prongs.

2. Material & Construction

3. Dimensional Standards
Cotter pins are sized by their nominal diameter and length.
Standards: ISO 1234, DIN 94, or ASME B18.8.1.
Measurement: The length is measured from under the eye (the short side) to the end of the shortest tine.
Common Metric Sizes:
Diameters: 1.0mm, 1.6mm, 2.0mm, 3.2mm, 4.0mm, 5.0mm, 6.3mm, 8.0mm.
Lengths: 10mm to 100mm+.

4. Key Performance Requirements
Ductility: The material must be soft enough to bend 90° to 180° without cracking, but stiff enough to resist vibration.
Corrosion Resistance: Stainless steel (A4) is required for marine or automotive underbody applications to prevent the pin from rusting and seizing inside the hole.
Shear Strength: While not designed to take primary loads, they must resist the shearing force of a nut attempting to rotate.

5. Common Applications
Automotive: Securing tie-rod ends, ball joints, and wheel bearing nuts (axle nuts).
Industrial: Locking clevis pins in linkage systems.
Bicycles: Retaining brake pads in certain disc brake calipers.

6. Installation & Safety Tips
One-Time Use: Never reuse a cotter pin. Once the tines have been bent and straightened, the metal experiences "work hardening" and becomes brittle. A reused pin is prone to snapping under vibration.
Proper Sizing: The pin should fill at least 75% of the hole diameter to prevent excessive "slop" or movement.
Bending Technique: Usually, one prong is bent back over the nut and the other is bent down against the side of the nut.