by Scott Hills
Our company has been in business for over thirty years, and the question we get asked the most often concerns drawer slides. You'll often see a manufacturer offer a weight rating for their drawer slides (100 lb., for example), and my customers want to know what this rating means.
There are two methods used for determining weight capacity of drawer slides: static (non-moving) and dynamic. In the static test, a weight of "X" pounds is put in the drawer and the sag is then measured. In dynamic testing, that same weight of "X" pounds is put in the drawer, but the sag is measured after repeated cycles of opening and closing. The resulting cycle count of dynamic testing is a major indicator of a slide's longevity after installation, and depending on the manufacturer's test criteria, between 50,000 and 100,000 cycles may be run.
For example, KCMA (Kitchen Cabinet Manufacturer Association) tests at a rate of 15 lb. per square foot of drawer (this includes slide, drawer, etc.) for approximately 50,000 - 60,000 cycles. Other sources of test criteria include OEM (Original Equipment Manufacturers), ANSI or in the US; LIGNA is the German counterpart.
The important thing to remember is that static capacity is always greater than dynamic. The length of the drawer slide being tested is another factor in determining strength. For example, a slide rated at 18 inch length 100 lb. dynamic is stronger than one rated at 16 inch length 100 lb. dynamic.
This information is not readily dispensed on your manufacturers'/distributors' catalogs. Recognized brand leaders may include a notation that describes the rating (100 lb. on 18 inch length, for example), but the majority of manufacturers will just note a weight determination. I always feel skeptical if no rating is mentioned at all.
Scott Hills was formerly Sales Manager for C.H. Briggs Hardware Co., a distributer of quality products for the kitchen and woodworking industry.