Kingpin Vs. Kingpinless Steel Casters: Understanding The Differences

3 November 2015
 Categories: , Articles

Choosing the right steel caster can make all the difference when it comes to designing carts for industrial material handling tasks. Swiveling casters that provide omnidirectional movement are usually designed with kingpin or kingpinless swivel sections. The following takes an in-depth look at both designs, highlighting their advantages and disadvantages.

Kingpin Designs

Kingpin swivel casters are the traditional go-to design for a wide variety of steel casters. A typical kingpin caster consists of an upper and lower ball race, along with upper and lower thrust bearings that help distribute loads during movement. These components are all held together by a bolt or rivet acting as a kingpin, hence the design's name.

The stationary kingpin provides the swiveling action, allowing the upper race and caster wheel section to rotate around the lower race and kingpin section. This design offers a number of advantages:

  • Traditional kingpin swivel casters are typically more affordable to purchase than their kingpinless counterparts.
  • The kingpin nut can be adjusted to add or remove resistance to the swivel motion. By restricting swivel motion, users can safely guide material handling carts along inclined areas and keep the caster wheel better planted on rough ground.
  • The kingpin can also be adjusted to account for swivel section wear, allowing the caster to last longer.

Kingpin swivel casters do have a glaring fault, however. Due to the nature of its design, the kingpin ends up transmitting the bulk of the forces absorbed by the caster. Heavy loads, harsh impacts and high speeds can create stresses that eventually fatigue and even distort the kingpin. In some cases, a weakened kingpin can even be sheared off during use, creating a dangerous safety hazard that could easily result in serious injuries.

For this reason, kingpin swivel casters are typically restricted to walking speeds of around 2 to 3 miles per hour. Using these swivel casters at faster speeds could add greater wear and tear on the bearings within the swivel section, especially if users take a turn at speeds of 5 or 6 miles per hour.

Kingpinless Designs

Kingpinless swivel casters offer a more straightforward approach in terms of caster design. Instead of using a kingpin to hold the swivel section together, kingpinless designs rely on a top plate integrated with a ball race and a yoke base containing the bottom race and ball bearings. Both halves interlock together, allowing the yoke base to freely swivel along the ball bearings sandwiched in between the top and bottom raceway.

There are plenty of benefits that put kingpinless designs at a distinct advantage over their traditional counterparts:

  • One major advantage of the kingpinless design is that it does away entirely with the kingpin, a common point of failure on kingpin swivel casters. Kingpinless steel casters offer a larger surface area, allowing caster loads to be distributed more evenly.
  • Kingpinless designs can be used at higher speeds than standard kingpin swivel casters. The wider base and lack of a kingpin means that these casters can be used for towing tasks.
  • Kingpinless swivel casters offer smoother, more uniform swivel action due to the wider base and better load distribution.
  • Kingpinless swivel casters also require less maintenance than an ordinary kingpin-equipped steel caster.

Unfortunately, one caveat that kingpinless swivel casters have is a distinct lack of adjustability. Unlike kingpin designs, there's no way to adjust the swivel section to accommodate ordinary wear and tear. Once the races have worn down, there's usually no other choice but to replace the entire caster. As a result, kingpinless designs often have a shorter lifespan than their traditional counterparts.

Using the above information, you can make an informed decision about which swivel caster works for your material handling needs. After you know what you want, reach out to a company like Garland's, Inc. for more information.