So, you twist the head off of a bolt, and the shank is imbedded in whatever you were working on…now what?

There are tons of articles and ideas floating around on the web on how to deal with this miserable problem and I would suggest spending some time surfing the web to educate yourself on some trick ideas on broken bolt removal. However, I’m going to give you some “Old School” fundamentals to think about!

  • Prepare the face of the bolt to be extracted. First, grind a smooth flat surface and then use a punch to make a mark dead center.
  • Using a small pilot bit, drill a hole dead center in the bolt. Once you have a hole started dead center, you can now switch to a LEFT HAND drill bit (a drill bit that drills in reverse). Choose as large a bit as possible without damaging the threaded wall of the hole. Many times a bolt will break loose and come out while you are drilling into it in a reverse direction.
  • If the bolt has not broken free, then insert the screw extractor that corresponds with the size hole you drilled. Use a pair of vise grips to grab the extractor and apply moderate pressure while turning the extractor counter-clockwise. The extractor should not bind into the broken bolt and begin backing it out. Be careful not to apply too much torque to the extractor. You DO NOT want to snap the extractor off in the hole.
  • If the bolt still will not break free, the only other option is to drill a new hole and either tap it to the next size up or consider going the helicoil route. Either way, it would be best to get help before drilling larger holes. It is possible to reach the point of no return!

 

 

Posted by Mark and Joni Corby

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