Yahu made the following comment in the discussion on "Electric Appliances and Mikva"
"Breaking does not mean that it can not work. As long as what you are doing affects the vessel in a 3 dimensional manner, e.g. adding on or engraving, then it is considered a vessel you made. It goes to follow that unscrewing a screw, taking it out, reinserting and tightening it would be enough. – Yahu Apr 22 '10 at 17:26 "
What is the source/s in the Poskim for this?