The lock bolt is in the mailbox does not always withstand the encroachment of the feeder bullies. Too primitive its form is thin and the iron from which it is made.
But if you replace the stock bolt with steel plate cross-section 20×3 mm, bent as shown, so just the box, no one will open.
Recommend to read
THE STORM “FIATS”
Soviet istrebitel-polutoraplan-15. In the early 30-ies of the last century in accordance with the existing at that period, the concept involving joint use maneuverable fighter biplanes...
ON THE ICE – WITH THE WIND
For living with a little bit of a big pond is always a great temptation to build something for the development of its open spaces. The boys excitedly knock together simple rafts who are...