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What your drawer actually weighs, and what the box weighs full

Two numbers nobody publishes because they depend on your tools. Both are arithmetic, and both change which box you should buy.

Two adjustments, both from published guidance. First, ratings are quoted per pair, not per slide and not per drawer side - a drawer described as 120 lb holds 120 lb in total. Half the internet gets this wrong in both directions.

Second, the published design guidance is to operate at no more than 70 to 80 percent of the rated capacity. The stated reasons are impact loads when a drawer is closed forcefully, uneven weight distribution inside the drawer, and material fatigue over thousands of cycles. Manufacturers rate slides at full extension, which is the worst case, and the guidance is to design to that worst case anyway because drawers get used at every extension.

Put a socket set and an impact set in the same drawer and you are at 42 lb before anything else, which is comfortably inside a 96 lb working load and comfortably outside a 60 lb one. That is the entire practical difference between a 120 lb drawer and a 75 lb drawer, and it is why the slide rating matters more than the gauge.

Nothing dramatic and nothing immediate, which is why people get away with it for years and then do not. An overloaded slide sags at full extension first - the drawer front drops a few millimeters and you notice it catching on the frame. Then the ball bearings brinell, which means they press permanent dents into their races, and the drawer starts feeling gritty instead of smooth.

After that it binds, and eventually a bearing race deforms enough that the drawer will not retract straight. None of that is repairable in a consumer cabinet; the fix is a new slide pair, and matching a slide to an old cabinet is harder than it sounds.

Manufacturers publish the empty weight, because it is a fact about the product. Nobody publishes the loaded weight, because it depends entirely on you. It is also the number that decides whether the casters and the garage floor cope.

One published 56-inch combo set is 604 lb empty on six 5 x 2 in casters. Add a realistic tool load and you are well north of 900 lb, which is about 150 lb per caster. On four casters the same load would be 225 lb per wheel. That is the argument for six casters, and it is not in any marketing copy. The casters page has what a caster rating covers.

• Heaviest things in the lowest drawers. Better cabinets run dual slides on the deep bottom drawers precisely because that is where the weight is meant to be - one published set uses double 120 lb glides down there.
• Do not spread one heavy set across two drawers to stay under a limit. It solves the slide problem and creates a retrieval problem, and retrieval is what you bought the box for. Buy the drawer rating you need instead.