Q: Some of the door knobs in my older house (1920s) have come loose and just keep spinning when I try to turn them. Is there a way to tighten old door knobs?
A: This question gets asked a lot by people who have pre-1940s homes. And fortunately the answer is, yes–these loose door knobs tend to be very easy to tighten! (I’m including a short video of the process, as well as a more detailed explanation below.)
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The problem comes about in the first place because door knobs were constructed differently back then. In older hardware, the turning shaft came through the door slab and connected directly to the knobs on either side. This meant that the knob had two jobs: it acted as a lever for turning the latch, and also acted as a fastener for holding the whole lockset together.
Engineering in modern door knob hardware solved this problem by creating two separate screws that pass through the handset hole and fasten into threaded shafts on the far side, clamping the lockset together. Now, the knob itself is only responsible for turning the latch–not for holding everything in place as well.
So, to answer your question, all you have to do to keep your old knob from spinning is securely fasten it to the shaft coming through the door from the other side.
To help things, look closely at the shaft in the picture above. You’ll see that it is actually square, and that the corners have threads cut into them. This is because the inner wall of the knob is threaded as well, and contains a little set screw for locking it into place.
To mount the door knob, you spin it clockwise onto the shaft, just like you’re turning a nut onto a bolt. You want to keep spinning it until it’s almost touching the plate on the door. But, be sure to leave a little slack at the end–about 1/16″. This will help the knob turn more easily.
Now, locate the little circular set screw on the knob. It will be somewhere along the handle neck, and will most likely have slot for a flathead screwdriver. (In some cases, there will be two set screws.)
These set screws move inward as they’re tightened, clamping down onto the shaft inside the handle, trapping it in place. BUT, it’s important that they fall on the grooved walls of the shaft–not the threaded corners, which they can damage.
So, as you’re spinning the knob into place, take note of the orientation of the shaft. Keep the square walls pointed up and down. This way, you’ll know to position the set screw roughly in one of the four locations perpendicular to the shaft.
When you’re knob is positioned where you want it, just tighten down the set screw with a decent amount of force. Don’t go overboard, and don’t damage the flathead slot on the screw!
Give the knob a test turn to make sure that it’s securely fastened, working it in both directions. If it still doesn’t want to grab, the shaft in the door may be worn down. If this is the case, you’ll probably have to remove it and get another one.
Likewise, the knobs themselves can go bad over time. What usually happens is that the bulb on the end detaches from a casing in the neck. The bulb won’t come off, but it will spin and spin, making it pretty impossible to get the neck to turn.
(This is how unwary party-goers often get trapped in bathrooms, resulting in claustrophobic freak-outs and embarrassing rescue operations!)
If you need to replace the shaft, the knob, or both, the easiest thing to do is go ahead and remove the hardware. Take it with you to an architectural salvage store somewhere and ask if they have a match. So many of these knobs get pulled out of old houses that they can actually be pretty easy to find. Just be sure not to lose the set screw! Put everything in a baggie to be safe.
Also, it’s important to note that both sides of the door work in the same way. The knob on the far side mounts to the shaft in identical fashion. So, it’s possible to have the same problem on both sides of the door. But, it’s fixed in exactly the same way.
That’s pretty much it. If you have malfunctioning door knobs in your old house, do your guests a favor–tighten them down. Rational thought tends to go out the window the moment that door won’t open!
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