What Is a Hinge Pin?

The metal rod that drops down through the interlocking knuckles of a door hinge and acts as the axle the door swings on. Tap it up from below to remove it. Squeaks live between the pin and the knuckle bore, so lubricant has to reach the pin itself.

Getting one out: close and latch the door first (it hangs steady with a pin missing), set a nail or nail set against the pin's bottom tip under the lowest knuckle, and tap upward with a hammer until the head rises enough to pull. Painted-over pins that won't budge take a flathead screwdriver wedged under the head. This is the one legitimate job for penetrating oil like WD-40, which frees stuck metal but is too thin to keep a hinge quiet.

What the pin tells you when it's out: black paste on the rag is metal dust from years of dry grinding. That is normal, and exactly what grease prevents. Deep grooves worn into the pin mean the hinge is past lubrication; new residential hinges cost about $5 each and install with the same screws. Coat a healthy pin with white lithium grease or silicone, work the door a dozen times, and the squeak is gone for years.