I'm afraid the limestone surrounds to our windows and doors are not dense enough to allow a thread to form cleanly, the "proper junk" fixings expand into a hole well at 100mm deep (I use 150mm) and don't crack the face off the stone, unlike the shutters that get blown in the wind if you don't hold them back, the repairs have been done with "proper junk" fixings, back in 2010, still there.
Mike
Mike