Tinkering: 2024-03-31: Door Lock Repair

This door would not close properly anymore, because the lock was broken. Naturally, I tried to repair it instead of just buying a new one.

The lock is quite old, maybe 80 years? This spring was not working properly anymore, and when I tried to bend it a bit, it immediately crumbled into pieces, because the metal had become brittle.

This was a good excuse to try to make a new spring, so I ordered some spring steel band. The original was 9mm wide and 0.8mm thick, but I thought that modern steel is probably more tough, and I ordered it 7mm wide and 0.6mm thick, which was perfect. It was very springy. I started by making it red hot with a gas flame in order to recrystalize it to avoid breaking it by bending.

And this is the new spring. It was really easy to make with some pliers, without any special new tools.

There are two such springs in the lock, the replaced one is for pushing the main anchor out.

To bend the inner loop into a square to fit it into its socket, I sanded down a bolt into a square. This was then used as a jig to coil the spring. After the first round using pliers, I got a nice tight fit and I could just turn the bolt to make more rounds.

The new spring fits nicely after sanding it a bit smooth.

To close this, the main arbor for the door handle needs to be bolted to the lock, because otherwise it is pulled apart by another strong spring. When opening the lock, I did not know this, and it fell apart. Luckily, I managed to understand how to put it back together. I hope.

This is the closed lock, with the auxiliary bolt removed.

And now the door works again.

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