Making a good earth connection

Several build diaries comment on electrical problems due to bad earth connections. How to make a good earth connection? Although the thread on the bold should be good enough we decide to remove the power coating where the earthing terminals go. How do you make a perfect "bald" spot...
- take 1 rivet
- put a scrap piece of rubber on it (in our case from an old bike inner tube)
- add a washer
- another scrap piece of rubber
- a small cut out disc of emery paper
- put in a drill (we used a pencil to hold the rivet so we could get the drill in):


The purpose of the washer is to have something firm to press the emery down. The purpose of the 2 pieces of rubber is to stop the washer and emery from rotating on the rivet.

and you get a perfect "bald" spot: