Sometimes, when working with machinery you might break the head off of a bolt or badly strip a screw. Now your task of removing the fastener is much harder. Fortunately, there is a type of tools called bolt or screw extractors made that can help. An extractor is inserted into a hole drilled in the bolt, tapped into place, and then rotated counter clockwise to remove broken piece.
I’m going to demonstrate their usage on my grease gun. I accidentally broke the hard tube coming out of the gun. This isn’t a bolt but the principle is the same. The piece that needs to be removed is pointed out with a green arrow.
These are a few examples of extractors. On the left are spiral fluted extractors and on the right are straight fluted extractors. Spiral fluted extractors have the flutes twisted around the body of the extractor so that they dig into the broken piece when you turn them counter clockwise. The straight fluted extractors also dig into the broken piece when you rotate them, but they have no twist. They can be used in either direction unlike the spiral extractors.
Here’s a closer view of both types.
Since the piece I need to remove is a tube I don’t have to drill a hole in it to insert the extractor. I inserted it and gave it a few light taps with a ball peen hammer to set it.
With the extractor in place, a wrench can be used to rotate the extractor counter clockwise.
In a few turns out comes the broken piece.
Sometimes removing broke fasteners can be more stubborn than in this example. For those times you will have to go more slowly and possibly use other methods such as heating or drilling.