I'm interested in a bolt extractor set. Problem is I'm confused by sizing of extractors. Are given extractor sizes in reference to the hex size (flat to flat of bolt head - dimension H in diagram below) or the normal dimension of the bolt shaft (dimension D in diagram below)? I assume its in reference to the hex size (dimension H) but I'm not sure. I am trying to remove a M16 x 1.5 wheel stud not a bolt (doesn't have a hexagon head). I need a stud or bolt extractor that will fit the shaft of the stud which has a normal dimension of 16 mm (dimension D in diagram below). A 16 mm bolt would normally have a bolt head that fit a 24 mm socket/wrench (dimension H). When trying to remove the lug nut from the stud I stripped the threads from the shaft of the stud. One would normally put two nuts on the stud and tighten one against the other then turn with a 24 mm socket/wrench to remove the stud but I cant do that because I stripped the threads. I could try to clean up the threads and try to get two nuts onto the stud but doubt the damaged threads would stand up to the torque that would be required to remove the stud. I hope the bolt extractor will have enough bite to take the required torque to break the stud loose so I can replace it with a new one. My question is what size extractor would I need to fit the shaft (16 mm normal dimension - dimension H below) of the stud for removal? Might just weld a nut to the stud but would be nice to have a set of extractors for future.

