A bolt is a metal rod that has a head on one end and a screw thread for a nut on the other.
There are many problems that can arise when trying to remove old fasteners. Most of the time, you’ll encounter a broken bolt head, rounded or seized nuts. There are several methods you can use to remove to broken fastener.
• If a portion of the bolt where the head broke off is protruding out, try grasping the remaining bolt with a vise grip pliers or a small pipe wrench and slowly turn out the bolt.
Vise-Grip 5-10WR Curved Jaw Locking Pliers with Wire Cutter
If it is a rusted and seized bolt Spray the threads (not the part your trying to grip) with penetrating oil and give it a couple hard raps with a hammer to possibly loosen the seized bolt before turning).
• A slot may be cut into the top of the broken bolt in order for a screwdriver to be inserted and remove the bolt.
• If the bolt is seized, applying a little heat to the parts and then rapping it with a hammer may loosen the seized part enough to turn the bolt.
• A file may be used to flatten the sides of the bolt in order to gain a better grip.
• Drill a hole in section of flat steel, place and weld the strip over the broken stud. An arc welder works best.
• Sometimes if the bolt isn’t seized you can use a sharp pointed punch and try driving the bolt in a counterclockwise direction. Be careful not to ruin the bolt any further if it doesn’t turn try another method.
• A screw extractor or broken bolt extractor can also be used .
Alden 8440P 4-Piece Grabit Broken Bolt and Damaged Screw Extractors Set
Use a center punch in the center of the stud. SE Punch Set, 8Pc 4 Brass 4 Chrome
Using a small diameter drill, drill a hole through the center of the stud, then use a drill size that accommodates the screw extractor . Then lightly tap the extraction tool into the bolt and back out the broken bolt.
• If all these methods fail, you can rethread the hole to use a new fastener. Drill through the bolt just below its minor diameter and use a tap to rethread the hole. If your working in a delicate area and fear the metal chips and filings that will be produced during the repair, try coating the drill and tap with some heavy grease in order to capture the metal shards and fillings.