# What causes standard door hinges to close up to a certain amount automatically?

Hopefully a relatively easy one to answer. :) My bathroom door has a standard hinge attached, that requires the door to physically be closed - this matches the setup of the other doors in my house. However, when fully opened, my bathroom door closes up to a certain point and then stops - this amount is consistent each time. What causes this to happen for certain doors, and not others? This is the only door to do this in this house, but I've seen others that have done something similar previously.

• can you include a picture of the hinge? The ones I'm familiar with do have adjustments
– JACK
Oct 2, 2019 at 19:57
• What causes things to move? Energy. From where might the door be getting energy if not from a spring? Gravity. Oct 3, 2019 at 13:34
• one upside down hinge or one out of alignment?
– dill
Oct 3, 2019 at 17:00
• "wear" could be an answer - a part of the hinge travel that is most worn over time, so slightly "lower" on a weight-bearing surface. Oct 3, 2019 at 19:44

## 3 Answers

The two hinges are not exactly one above each other, in 3D. One of them is slightly left, right, front or back, relative to the other.

As such, the line going through both hinges forms a vector in space. If this vector is not straight up, when the door rotates around it, the door will go higher or lower.

Gravity is pulling the door down. As such, it will try to go to the position where the door is lower.

(following comments, I assumed passive hinges. Do you have a hinge that is supposed to close automatically?)

• Gravity is the answer. Friction is the arresting force. Oct 2, 2019 at 20:47
• as well, the hinges could be independently non-plumb, or they could be relatively bowed, concave, crooked, etc. Oct 2, 2019 at 21:09
• Old houses have this a lot - it could be the frame is not actually vertical, the frame and/or door has bowed in strange ways etc. You may find temperature or moisture affect it too - as they may alter the shape of the frame/door a little throughout the year. Oct 3, 2019 at 9:18
• "forms a vector in space" that's just sciency sounding mumbo-jumbo that doesn't explain anything. It's easy to picture what's happening with out-of-line hinges if you imagine the door as two independant halves (as if you'd sawn it in half horizontally). As you swing the door, two halves would move relative to each other (because the hinges are not aligned) and you'd need to apply a load of force to make the two halves line up, bending the door, the hinges and the frame like a big spring. This spring force is what moves the door. Oct 4, 2019 at 15:05
• This answer needs more linear algebra. Oct 4, 2019 at 20:47

The most likely causes are a tilt in the wall or a poorly hung jamb. In either case the hinge jamb is out of plumb. In your case it's leaning toward the center of the door swing. The door slab is actually lower in that partially-open position, so that's where gravity puts it. This is more common with solid-core doors, which are much heavier and therefore overcome hinge pin friction more easily.

An old hack is to pull the hinge pins one at a time and bend them. Lay them between two blocks of wood and give them a pop with a hammer. Start with about a 1/8" bend in each hinge. This may introduce enough friction to counter gravity.

The right fix is to actually re-hang the door. However, if the lean in the wall is severe enough, you won't be able to hang the door plumb and not have a substantial misalignment, which pays heck with the casing.

If you care to investigate with a 4' or longer level, report back and we'll address it further.

• @JimmyFix-it Bend the hinge pins? How will you get them to fit if they're no longer straight?
– Mast
Oct 3, 2019 at 8:26
• You don't even need to remove the pins to bend them. If adding friction is your goal, then a good smack in the direction of the jam with a hammer on the lower corner of the hinge usually does enough damage to introduce friction, without causing damage to anything else. Oct 3, 2019 at 13:33
• Yikes. I have visions of screws torn loose and hinge leaves bending. I'd rather keep the modification hidden and reversible. Oct 3, 2019 at 14:26
• @dotancohen - you and I know how to fix things with a hammer. Not something I'd recommend to a noob though. Oct 4, 2019 at 3:06

In the UK it's a rising butt hinge when you open the door it rises slightly when it opens and the weight of the door makes it close. This looks like a normal hinge. Note the slight wedge between the two parts of the hinge.