The caster / wheel including all its parts, must be in good operating condition; the swivel section & bearings must be tight without excessive movement (other than the obvious intended swivel action) and must turn smoothly and freely without grinding of the bearings, unevenness, wobbling or excessive resistance. The surface of the molded, cast & stamped parts shall be smooth without pot marks, deep gouges, bubbling of materials, inconsistent coloring, excessive grease, dirt, grime or rust. All metal Parts must have a good consistent finish of Zinc, Nickel, Chrome or paint (unless they are made from stainless steel or are intended to be un-plated parts treated with a rust inhibitor). All Parts must be free of burs and sharp edges and have a uniform look of even plating. The plating shall not have not have blemishes, flaking, oxidation of of the finish or un-plated sections, inconsistent coloring or excessive shiny or dull spots creating an undesirable distinction with the rest of the finish.

Specified Measurements

All Parts that Have critical or specified measurements are checked to assure they are within an acceptable range of tolerances.

Weight Capacity, Roll-ability, & Impact Tests

(Tests conducted by machines and gauges.)

The object of these tests is to determine a minimum factor of safety and the operational load capacity for the casters in normal caster use applications; without functional impairment or permanent deformation of the caster; preventing failure and ensuring the safe operation thereof.

Static Load Test (Stationary)

Test is conducted by placing the caster upside-down and applying 4 times the assumed weight capacity on the caster by the means of a pneumatic press for 1 minute and then removing the weight. The Caster is then checked for integrity to assure that weight bearing parts show no sign of failure, defects or deformation, and that all moving parts operate smoothly and correctly.

Dynamic Load Test (Rolling)

Test is conducted by the means of a testing machine made for the express purpose of testing casters & wheels under a rolling load. Weight is applied by the means of free weights, stacked up on a press apparatus (or lift arm). The rolling action is provided by the means of a turn table positioned underneath the press apparatus. The caster is attached to the underside of the press by the means of its mounting fastener. A compressive weight load of the assumed weight capacity will be applied on the caster while it is rolling on the turntable. Steel plates are mounted to the turntable (as obstacles) in the path of the caster to simulate shock loads and abuse the caster may encounter in normal usage. Obstacle heights vary per diameter size of the caster wheel. A 1/8" high x 2" long obstacle is used for wheels up to and including 6" in diameter and a 3/16" high x 2" long obstacle is used for wheels greater than 6" in diameter. The turntable is ran at 2 miles per hour until the caster has traveled over 10,000 obstacles for plate casters and 500 obstacles for stem casters. In the case of the stem caster, once the obstacles are removed the caster should continue to run under a load for 9500 turns of the turntable, [same overall distance as the plate caster will travel;= 10,000 turns times the diameter of the rolling plane of the caster on the turntable (rolling plane is 3 meters = 9.8425 ft. 10,000 rotations x 9.8425 ft = 98,425 ft or 18.64 miles). The caster rolling on the turntable simulates normal caster use under a load; by running the turntable for 3 minutes on and 2 minutes off, this process is continued for the entirety of the test. (Run time for the test takes approximately 16 hours: 9-1/2 hours rolling and 6-1/2 hours stationary).

The testing machine is computer operated to adjust the height, weight, and speed of the test, as well as record the data acquired during the test. There is a safety switch under the press that is adjusted to the height of the caster; which will detect any variance of the height due to failure. In the advent of a failure the safety switch being tripped, will shut off the turntable and the computer will record at what point the failure occurred. A web-cam is positioned to watch the test being conducted; interested customers may view their tests being ran via the internet. After the test is completed the caster will be checked for integrity and signs of failure or fatigue that may impair the caster from functioning correctly, special attention is given to the inspection of the swivel and wheel bearings; all moving parts should operate smoothly and correctly.

Note: A critical feature of the design of the testing machine is the weight stack. It is important to state that when the caster rolls over the obstacle, the weight stack is lifted by the caster as it rolls over it; if the caster is 5" tall, it remains 5" tall while rolling over the obstacle. Using a pneumatic or mechanical press to run this test will not provide the space needed to allow the flexing or lifting action when the caster attempts to roll over the obstacle; resulting in assured failure. (It is not reasonable to expect a caster that is a 5" overall height to rollover a 1/8" obstacle without permitting the caster to lift the weight and therefore ramming a 5" caster through a 4-7/8 space; and expect no damage)!

Tests adapted from the 2004 ANSI & ICWM testing standards for Casters & Wheels.

Download the entire Testing Procedures and Acceptance Criteria (PDF) manual.