Why a drawer seizes — and why oil makes it worse
A ball-bearing slide is three parts sliding inside each other: an outer rail bolted to the cabinet, an inner rail bolted to the drawer, and a cage of small steel balls rolling between them. It works on one condition — the balls must roll, not drag. Anything that stops them rolling turns a slide into a brake: kitchen grease mixed with crumbs forms a sticky paste, hair and lint wrap around the cage, and a single loose screw tilts the rails so they pinch the balls.
This is why WD-40 is the wrong tool: it's a solvent with a thin oil, not a lubricant. It dissolves the old grease, feels wonderful for a week, then collects dust into a grinding paste. Silicone or dry PTFE spray leaves a film that doesn't hold dirt; for wooden runners with no metal at all, a candle or a bar of dry soap rubbed on the contact points is the old carpenter's answer.
Match the evidence
- Grinds the whole way, or hitches at the same spot → Grime in the race. Take the drawer out, dry-brush the channel, wipe with isopropyl alcohol, let it dry completely (water is how you grow rust), then two thin coats of silicone, cycling the slide by hand between coats.
- Glides when empty, sticks when loaded; wobbles or one side hangs → Loose screws, usually the rear pair — they take the hit every time the drawer is slammed. Tighten every screw on both rails; if one spins forever the hole is stripped, so pack it with toothpicks and wood glue and re-drive.
- Comes out crooked, or you can hear metal grinding and see gaps in the cage → Bearings have left the race, or the rail is bent. This one isn't fixable: measure the length, buy a matching pair, and replace both. Mixing a new slide with a worn one guarantees a crooked drawer.
Never pull harder when it sticks. The cage is held by friction alone — a hard yank shoves it out of the track, and a twenty-minute cleaning becomes a slide replacement. And before you take a drawer out, empty it: a loaded drawer that comes free lands on your foot.