I've used these a few dozen times now, mostly on stripped-out Philips head screws with good results. The spiral flutes are deep and sharp compared to some other types, so they bite rather well. The left-hand drill bits really help too, I had a few screws come out with those alone.For best results learn how to use these correctly! I've seen them used wrongly with bad outcomes. Start with a smaller extractor first (you can maybe go bigger after), drill into the head of the screw with the LH bit, lightly tap the extractor into the hole with a hammer till it bites, then turn left with a good tap wrench. BTW, you should have put some good penetrating oil on the screw before doing anything else.
Rating:
[5 of 5 Stars!]