Of ALL the different types of broken bolt extractors I've used bar none, this is my favorite type! As I mentioned in my previous Reel, I dislike any type of extractor that is a wedge shape and tends to expand the bolt from the inside making it tougher to remove. I much prefer this splined extractor type, each size is a 3 piece matched set: drill bit(LH), splined extractor and sleve/nut. The reason this type works well is because the points of the extractor are much smaller, so as long as you do

Broken Bolt Extraction Technique