At work, we have older network box(from what I could find, it could be Datacom 19" RACK) without a lock, that always swing open. So I made simple lock/latch.

Locking mechanism turns only 90°. Latch is held to mechanism with M3x6 screw in either M3 heatset insert, or selftap plastic thread.

“Keyhole” is for standard electrical box 6mm square key. If you don't have any, I've made model with hole for press fiting 7x2,5mm magnet.

Model files:

[https://cad.onshape.com/documents/1797e546dc01f3175a64baf6/w/58a8e1cd1dcf8d7e78fa7ae2/e/b2e9cf82798b62d00aa5c68d](https://cad.onshape.com/documents/1797e546dc01f3175a64baf6/w/58a8e1cd1dcf8d7e78fa7ae2/e/b2e9cf82798b62d00aa5c68d)