Linch Pins

A linch pin is a wire loop that slides through a drilled hole in a clevis or axle shaft. Pulling force tries to straighten the wire — the tighter the bend radius, the more load it holds before deforming. Galvanised steel resists corrosion long enough for outdoor farm use; stainless lasts longer in salt spray or slurry, but you'll pay more and most buyers don't need it.

Diameter matters more than length. Match the pin wire thickness to the hole — too thin and it rattles loose under vibration, too thick and you'll force it and crack the parent metal. Common sizes run 3 mm to 6 mm wire diameter for trailer balls and implement pins; anything heavier usually takes an R-clip or split pin instead.

Check the hole is drilled cleanly and the shaft isn't worn oval before you fit a new pin. If a linch pin keeps walking out, the hole has enlarged — drill oversize and step up to the next wire gauge, or replace the clevis. Spare pins live in the toolbox; an assortment covers most jobs without guessing sizes in the yard.