A friend who has become blind and wants her iron gate to squeak so she knows when she has visitors coming. The house has a locked door and doorbell, but everyone has to open the gate first.
I tried wetting the hinges with vinegar over a couple of days and the gate does squeak a little, but I can't help but think there must be a better way to get a louder sound.
Best Answer
This feels like an XY problem - you imagine a squeak would work, so you ask about how to make a squeak. Instead, ask "how to alert a blind person when someone opens the gate"
I'd go with an Infrared interrupter beam right behind the gate, like a shop. Have it wired to a chime inside, and do lube the gate properly to help it last longer.
If you want to be fancy, a wireless or portable chime unit could be ideal, at the cost of needing a charge or new batteries periodically.