A loose doorknob is not only a frustrating thing to deal with every so often, when it spins in your hand instead of opening the door, but it also poses a security hazard. What do you do when an emergency requires you to leave the house immediately, and the door poses a hindrance? Perhaps you have tried to tighten the screws of the doorknob set, and find, to your dismay, that it still becomes loose after a week. This problem usually happens when the set screw has loosened up, failing to give enough pressure on the threaded spindle. This usually comes about when a doorknob is worn out from use. Thankfully there is a way you can fix this kind of problem without needing to replace the entire doorknob set, by using a thread-locker, or a special blue compound that will ease your doorknob issues.

Step 1. First, you will need to remove the doorknob. This is an easy task, as you will simply need to loosen one or perhaps two set screws that are holding it in place against the spindle. From there, unscrew the doorknob from the spindle.

Step 2. As soon as you have removed the doorknob from the spindle, remove the set screws. Be sure to work in a clean work area and carefully set the screws aside.

Step 3. The next step will require you to apply the thread-locker to the set screws. Thread-locker typically comes in two colors, red and blue. The red thread-locker is permanent, while the blue is removable. Interestingly, the two types are typically packaged in the same blue-color packaging, so be sure you get the blue thread locker, as the permanence of the red thread-locker will call for 450 degrees of heat if you ever need to remove it. Purchase the medium strength blue thread-locker; this type may be easily removed using hand tools. To start applying, shake the container first. Then apply it relatively sparingly to the screw threads, keeping the plastic bottle tip from touching the surface of the screws. The compound will cure between the threads and form a one-piece assembly that technically “locks” together.

Step 4. Once you have applied the thread-locker to the set screws, reinstall them, lightly screwing the screws into the doorknob for only a few turns, just enough to get them held in place.

Step 5. Reinstall the doorknob, noting the orientation of the flat surfaces of the spindle, making sure it matches that of the set screws. When you are screwing the knob onto the spindle, stop the screwing motion once the set screw already gets into proper orientation. Fully thread the knob onto the spindle, but be sure to avoid over-tightening the knob. Once your doorknob is back in place, you can continue using it and enjoy knowing that it will never loosen again.