Arduino based expression pedal

Hello,
I''d like to make a Arduino based expression pedal for a dyi organ project. This is a single midi pedal that rotates gradualy and is used to change the volume. I've already got the electronic part working, if anyone is interested i can share the link wher e i found the code.
Now i'm thinking on how to do the pedal itself and the machanical parts. I have some mouldable plastic (melts at 60 degrees) and some wood i can use. In particular i'm not sure where to get the pivot, and how to fix it to the pedalboard:

The idea is something like this:

Any advice on where to get the pivot ?
thanks