Stud Extractor Universal 1/2 Inch Drive

This did exactly what it claims. In my case I needed to get the 7/16 exhaust manifold studs out of a flathead ford tractor. The studs go into the block and if you break one you can't just pull the head and take off to the machine shop. The extractor arrived earlier than expected and was in good shape. Basically this works like a drill chuck, the inner nut being left hand threaded and the outer knurl right threaded. You place it over the stud and tighten (inner nut left, outer right) then turn the inner nut left to remove the stud. I was able to get the studs out without going to an impact, though this is impact rated and says so in the instructions. The manual suggest starting with a low power setting if you use an impact. Warning, on my impact, the power settings only apply to right rotation and you have to drop you're air pressure at the regulator to affect the power left. When I started to turn the inner nut (left) I was a little concerned that the nut was turning but the outer wasn't and therefore the stud didn't seem to be moving. What I found after the stud was out; the jaws were cutting into the stud. The outer knurl has a 36mm hex nut on top and you will need a 36mm wrench to get it opened back up. I had trouble finding a 36mm wrench and finally bought a cheapie from Northern tools, but don't skip this you won't get this back open without a 36mm wrench, or putting it in a bench vice. Once opened the teeth from one of the jaws was still embedded in the stud and I ended up using a punch to tap it loose. I used this on 7/16 studs. I'm not sure it will work on 1/2 inch. I tried to open it all the way up and slide a 1/2 tap (what was handy) in and it wouldn't clear. It was however very close and I believe taps are slightly oversized so it may actually work on a ½ inch stud. Finally, this is expensive but when weighed against the cost (time, frustration and money) of breaking off studs it's a bargain. It did what good tools do, made the difficult anticlimactic.