I was recently burglarized and all of my tools were stolen. I have gradually been replacing them as I can afford them. But I have not purchased a stud finder yet. I have been trying to locate a wall stud by knocking, and with magnets to no avail. So in desperation, I took a 3/32 drill bit and drilled 34 holes that were spaced 3/4" apart and never struck a stud.