The Problem
A door that drags across the top of the jamb usually isn't warped — it's hanging a fraction out of plumb, so the gap tapers from wide at the bottom to nothing at the top. The standard fixes are slow: pull the casing and re-shim the jamb, or unscrew a hinge and pack cardboard behind the leaf to kick the door over. Both mean taking the door off and guessing at the shim thickness before you can test the result.
The Technique
This one adjusts the hinge itself, with the door still hanging.
- Tap out the pin on the top hinge only. The door stays supported by the middle and bottom hinges.
- With the top now loose, push the door over until the gap along the top and latch side looks parallel, and hold it there with wood shims wedged between door and jamb.
- Look at the hinge. The knuckles on the door leaf no longer line up with the knuckles on the jamb leaf — that offset is exactly how far the door had to move.
- Grip the door-side knuckles with an adjustable wrench and bend them back into line with the jamb-side knuckles. Work in small bites along the leaf rather than one big pull at the end.
- Pull the shims and drop the pin back in. The bent knuckles now hold the door in its new position permanently.
The offset you closed up in step 4 is the correction. You're not forcing the door anywhere — you're reshaping the hinge so that its natural resting position is where you want the door to sit.
Pro tip: Bend less than you think. The knuckle offset is a small distance amplified across the width of the door, so a knuckle you've pulled too far gives you a door that swings itself shut from any position. Set the pin, close the door, and check before you decide you're done — going back to take a bend out is much harder than adding to one.
Safety note: This works on ordinary pressed-steel butt hinges, which bend. Cast or antique iron hinges snap instead of bending — if the hinge is old, heavy, or decorative, shim the jamb rather than reshape the hardware. Support the door while the top pin is out, especially on a solid-core or exterior slab, and keep your fingers clear of the gap when you pull the shims.