Caster Duty Classes {The Load Capacity of a Caster is Determined by its
Wheel Diameter, Treat Width, and Treat Material}

Caster Duty Class Product Differences

Feature	Light Thru Medium Duty	Medium Thru Heavy Duty	Heavy Thru Super Duty
Typical Method of Construction	Stamp Formed	Stamp Formed or Welded	Stamped/Forged & Welded or Forged, Machined & Welded
Typical Steel Material Thickness	Up to 3/16"	3/16' to 1/4"	1/4" and Up
Swivel Caster Ball Bearing Diameter	Small	Larger	Largest
Swivel Caster Kingpin Size	Small	Larger	Largest
Wheel Diameter	Small	Larger	Largest
Wheel Tread Vl�?dth	Small	Larger	Largest
Wheel Axle Diameter	Small	Larger	Largest
Caster Rated Load Capacity	Lowest	Higher	Highest
Typical Method of Movement	Manual	Manual/ lnternittent Powered	Intermittent Powered I Continuous Powered
Typical Speed of Movement	Slow	Slow/ Medium	Medium/ Fast
Cost	Lowest	Higher	Highest
Finishes Available	Zinc, Copper Oxide, Nickel, Chrome	Zinc, Epoxy Coated, Spray Enamel, Yellow Zinc	Zinc, Epoxy Coated, Epoxy Powder

DEFINITIONS

Axle: A circular sectional part on which the wheel may revolve either directly or with the use of anti-friction bearings. Typical axles are; rivet. nut & bolt, nut & bolt with a grease hole, and nut & bolt with a grease fitting.

Cold Forged Construction: A process of cutting, bending, or spinning metal into components; also known as cold forming. Cold forged casters withstand mild shock loads and are appropriate for most intermittent applications.

Core: Part of the wheel comprising the hub, web and the rim suitable to receive a tread.

Directional Lock: Device to prevent the rotation of the fork of a swivel caster in one or more predetermined positions. This device can be used to convert a swivel caster to a rigid caster.

Dust Cover: Metal shield covering the raceways to help keep contaminates out of the swivel bearing (raceway).

Finish: Coating on the caster that helps prevent rust and corrosion. Most common types are; commercial clear zinc, copper oxide, epoxy coat, yellow zinc, nickel, chrome, epoxy powder coat, epoxy powder over yellow zinc, stainless steel.

Fork: Supporting structure with one or more legs designed to accommodate an axle and wheel.

Hardened: Process (sometimes called heat treated) that increases the surface strength of a steel component, lengthens the wear life of the component

Hollow Kingpin: Through hole on the upper side of the housing/rig suitable for the connection to mobile equipment.

Hot Forged Construction: A process of working hot metal into an open die by repeated impact of a mechanical hammer press. The metals grain flow is aligned to develop maximum impact strength and fatigue resistance. Its superior strength makes it suitable for prolonged use as well as for withstanding severe shock loads.

Kingpin: A rivet, or threaded stud or bolt with nut, that holds the mounting plate and fork assembly of a swivel caster together. Forged as an integral part of mounting plate on high load capacity casters for maximum rigidity and strength.

Kingpin Nut: The nut on the bottom of a threaded kingpin or bolt that permits the disassembly or adjustment of swiveling components.

Kingpinless Caster: A swivel caster that replaces its kingpin with a precision, full contact ball bearing raceway.

Legs: Axle support brackets on welded fork casters which extend down from the fork base of a swivel or rigid caster.

Load Capacity :Maximum load in pounds or kilograms, which can be carried by a wheel or a caster.

Mountlount Plate: Upper part of a fork, with or without holes or slots for connection to a flat surface by bolting or welding.

Mount Stern: Vertical upper part of the fork to fit into a socket, threaded boss, or other receptacle.

NSF International Certified: Develops standards and provides third-party conformity assessment services to govemment, consumers, and manufacturers of products and systems related to environmental and public health safety.

Offset: Distance measured horizontally between the vertical swivel axis of the caster and the axis of the wheel.

Overall Height: Distance measured vertically between the ground and the top mounting surface of a caster.

Retainer Washer: A steel or plastic washer pressed into the hub ends of some roller bearing wheels to hold the bearing in place.

Rigid Caster: Assembly including one or more wheels in a rigid fork.

Flollablllfy: The ease of starting and rolling, measured by drawbar pull. This is determined by load, floor conditions, wheel type and sizes, and bearings.

Side Mount Pinch Type Brake: Brake lever pushes the legs of the fork against the wheel to stop wheel rotation.

Side Mount Strap Type Brake :Brake lever lowers the strap to the wheel tread to stop wheel rotation.

Shock-Absorbing Caster: Caster specifically designed to absorb shocks and impacts.

Spanner Bushing: A non-rotating sleeve of seamless steel tubing that fits over the axle in many casters. Serves the dual purpose of providing a smooth inner raceway for the wheel bearings, and strengthening the caster but permitting the legs to be tightened against it.

Stamp Formed Construction: A process of forming a component through a die, by progressive impact.

Swivel Bearing (Raceway): Device that allows the free rotation of the fork around its swivel axis bearings, and strengthening the caster but permitting the legs to be tightened against it.

Swivel Caster: Assembly including one or more wheels in a housing/rig which rotates freely around a venical axis. The axis of the wheel is normally offset to the swivel axis of the fork.

Swivel Grease Seals: Seal to protect swivel fork raceways from contaminates and retain grease.

Swivel Radius: Distance measured horizontally, between the vertical swivel axis and the most protruding point of the caster or its accessories. This radius defines the minimum circle in which the caster is free to rotate 3600.

Thread Guard: A disc located between the fork and wheel to reduce accumulation oi strings, threads. tape, and floor debris between wheel bearing and axle that could inhibit wheel rotation.

Total-Lock Brake: Device to stop the swivel bearing and wheel rotation simultaneously.

Trailing End Type Brake: Brake lever makes contact with the wheel tread holding the wheel stationary. More accessible than the side mount strap type brake.

Tread: Outer surface of a wheel or a tire, in contact with the ground.

Tread Width: Width oi the tire measured at the widest point and parallel to the revolving axis.

Wheel: Circular structure able to rotate on an axle, either directly or with the use oi bearings. The extreme part of the structure is in contact with the ground.