I need to replace the cylinder in our front door lock (just bought the home and need to make sure nobody but us has the key). However, the screw that fixes the cylinder in place gets stuck. It gets progressively stuck, and so much so that it makes it very hard to get it to screw back in, and I don't dare try to force it further due to the risk of it just getting completely stuck.

I thought perhaps it was getting stuck in part of the door mechanism, so I unscrewed the front panels, and you can see the screw. It appears to be getting stuck just before the last part of the screw that sticks out at the end is about to enter the cylinder, and while I can't see anything wrong with it, I assume that means the screw is bent or the thread is damaged there, which would explain why it is so difficult to screw back in.

Other than calling a locksmith, my only idea is to take a small, narrow hacksaw and saw the end of the screw off through the slit next to the cylinder, and try again. Is this the right approach or is there something I'm missing (e.g. it's something entirely different, sawing the screw off might saw through some other part of the lock mechanism, or I'll never get the sawed off end out and it will break the mechanism)? Attached a video showing the screw inside the mechanism, and where it gets stuck.


  • Can you separate screw and cylinder and door successfully? That's what I get from the text, but it contradicts the title of the question. Is it possible that screw and cylinder have (only slightly) different threads?
    – Jasper
    Oct 26, 2020 at 18:17
  • Somebody in the past may have crossthreaded the screw and messed up the threads either on the lock or the screw itself. With the cylinder out, are you getting exactly the same issue? And maybe I'm misunderstanding, but I can't think of any circumstance where you want to be hacksawing stuff inside your lock. Oct 27, 2020 at 0:32
  • Sorry if I wasn't clear; I can't get the screw out of the cylinder, which means I can't get the cylinder out of the door. It's entirely possible the threads on the cylinder and the screw don't match, but the first 1/3 or so, which already has the thread inside the cylinder, comes easy. If somebody damaged the thread of either screw or cylinder in the past by cross threading, what are my options?
    – Acrofales
    Oct 27, 2020 at 7:12

1 Answer 1


Problem solved. It was indeed a cross-threaded screw as the comments said. I was afraid to get too enthusiastic about using pliers to unscrew it, in case it got utterly and entirely jammed halfway through. The local hardware shop said that in that case I could just take a hammer to the cylinder (after turning the key to where the pieces line up) to break the screw off and tap the cylinder out. So with that as a backup option, I used more elbow grease with the pliers and was able to unscrew it. No hammering required.

  • No hammering required”. How anti-climactic And rather disappointing.
    – Alaska Man
    Oct 31, 2020 at 16:19

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