How does a screw extractor work?
How does a screw extractor work? |
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All screw extractors perform the same job of extracting screws and/or bolts, however, they do this in different ways.
Screw extractors all have their own designs to extract a variety of sizes and types of screws. |
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Spiral flutes |
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Extractors with spiral flutes require a pre-drilled hole to be formed in the fastener in order to remove it. Their tapered flutes are then screwed into the pre-drilled hole in order to grip the screw or bolt securely. |
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These extractors have ‘reverse’ spiral flutes, which means that the extractor needs to be turned anti-clockwise in order to bite and grab the screw or bolt. | |||
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If the extractor is rotated clockwise, the flutes cannot ‘grab’ the material, and will simply turn in the hole. | |||
Straight flutes |
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Straight flutes also require a hole and are usually longer and gradually tapering, allowing them to wedge themselves against the inside of a damaged bolt, screw or stud. | |||
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They can loosen left hand threads when turned clockwise and right hand threads when turned anti-clockwise, as the flutes dig into the damaged object. | |||
Burnishing end (drill out) |
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The burnishing end is a drill bit, that can come individually or on the same tool with an extractor of a corresponding diameter. | |||
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It has a round body with a pair of cutting edges that dig and reshape the inside of the screw or bolt.
It needs to be drilled anti-clockwise to dig and reshape the inside of the screw or bolt, to accommodate the extractor. |
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