Hello, I have the following problem I bought me an additional 50L compressed air storage tank so only the boiler… at the drain screw it was not completely tight and wanted to change these and saw that the screw was already turned round… then have the screw drilled up as on the picture to watch it continue how it is no longer possible because I no longer have such a large drill….has someone got a hint like me the brass screw out without damaging the internal thread ?? Mfg