What is the kingpin of a caster?

The kingpin is the central rivet or bolt that locks together all of the critical swivel components of an assembled caster; majority of casters in today’s marketplace are kingpin style casters due to cost and performance effectiveness. The kingpin travels through the top plate (or can be integrally forged into the top plate on heavier duty casters), the upper load bearing raceway, the yoke base, and the lower thrust bearing raceway and its retaining button. It is then properly staked (rivet) or torqued down (bolt) to allow for just the right amount of clearance for swivel performance and operational durability.

Why is the kingpin and its size important?

Given the construction of swivel casters and its critical role of locking together all swivel section components, the kingpin absorbs the brunt of the force transmitted through the caster as it swivels and handles the working load and any floor imperfections/debris. Over time, the kingpin can strain due to these factors and start to stretch or bend (especially if the kingpin rivet/torque was not appropriately performed when the caster was manufactured). This can lead to the deformation of the kingpin, which will result in loose raceways and even the loss of ball bearings–causing early swivel and caster failures.

So what is the difference between 5/8″ and 3/4″ kingpins?

Most casters in today’s marketplace use 5/8” rivet kingpins on 2″ wide casters. Given that this is one of the most critical components to a casters life, Colson Group tested and upgraded its USA-made 2″ wide casters to a stronger 3/4″ kingpin. This upgrade to a 3/4″ kingpin on one of the industry’s most popular casters proved to produce over 40% longer life in the rig (the caster assembly less the wheel) over leading 5/8″ kingpin internal and competitive alternatives. This additional durability provides longer life to industrial customers and is fully backed by our 3-year warranty on both our Albion 16 Series and Colson 4 Series series that now feature this 3/4″ kingpin.