C15 Fuel tank badge set-screw snapped off

[Tigerfeet]

So...  the tank badges on my project C15 were both loose. The set-screw on the right had a damaged slot and wouldn't shift. So I carefully drilled the head off and found a relatively shiny (definitely not more than a few years old) remaining portion going into the threaded hole. After applying some penetrating fluid I got the mole grips on the remains - and after a couple of what seemed like succesful turns - I had snapped it off. RATS!

Reading up around the topic I discover that BSA made these with a 3BA tapped hole - and it seems that lots of the current dealers sell set-screws for the tank badges that are not 3BA. So I suspect that I have remains of an incorrect set screw cross-threaded into the tapped hole. (I've just measured the threads on the snapped-off remains, and the best fit is 0.75 metric and 36tpi imperial - which is very close to 34.8tpi for 3BA so maybe it was correct?)

Given the 3BA size, I'm inclined to drill the remains out with the correct drill size for a 3BA tap, and then retap the hole. Does anyone have alternative / better suggestions?

[neil1964]

Sounds like you have it covered.
The lazy ones of us would probably drill it and use a self tapper (tip ground off).
How much depth have you got behind the screw?  Enough for 1st, 2nd and plug to run through?