Anatomy of a Stem Caster: Your Caster Connection

Morgan Hughes of Caster Connection explains the various types of stem mount casters: grip ring stem, square stem, hollow kingpin, threaded stem, grip-neck stem, expanding stem/expanding adapter – and options such as tack-welding and dust caps.

Grip-Ring Stem Caster

Grip ring stems have a small friction ring that keeps the stem in the round hole within the cart. Grip ring stem casters are commonly found on mop bucket casters, office chair casters.

Threaded Stem Caster

Threaded stems have a distinct width, thread count and length, ranging from 3/8 to 3/4″ wide. This is the most common type of stem caster.

Square Stem Caster

Square stems fit into a square tube. The stem is held in place with a cotter pin. This attachment type is found on shelving racks.

Expanding Stem Caster

Expanding adapters fit into a variety of inner diameter round or square tubes depending on adapter kit and size of tube. This attachment type is great for hollow legs and tubes.

When the stem is inserted, the rubber adapter is expanded to fit the size of the hollow tube or leg.

Hollow Kingpin Caster

Does not have a stem, but rather an opening for a bolt to be inserted into the opening to act as the stem. This is a great option if you can’t find a caster with the threaded stem size you need.