Our other sites:

How does a screw extractor work?

Shop for Bolt Extractors

Depending on the screw extractor you are using, they all do the same job of extracting screws and/or bolts. However, they all have their own designs to extract a variety of sizes, types and have specific ways of extracting. 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.

Spiral flutes

The spiral flutes have to fit into a pre-drilled hole to be able to grab the screw or bolt. A screw extractor is able to fit into a pre-drilled hole because of its tapered flutes. 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. 
A spiral flute extractor has reverse spiral flutes that are designed to grab and bite the damaged, broken or embedded screw or bolt. 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.
The reverse spiral flutes need to be turned anti-clockwise to be able to bite and grab the screw or bolt. Turning the extractor clockwise would not grab or bite the screw or bolt as the flutes are not facing that way. If the extractor is rotated clockwise, the flutes cannot ‘grab’ the material, and will simply turn in the hole.

Straight flutes

The straight fluted extractor has gradual tapering and long flutes which wedge against the inside of a damaged bolt, screw or stud. 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.
It can loosen left hand threads when turned clockwise and right hand threads when turned anti-clockwise, as the flutes dig into the damaged object. 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)

The burnishing end is a drill bit, that can come individually or on the same tool with the extractor that matches its diameter. The burnishing end is a drill bit, that can come individually or on the same tool with an extractor of a corresponding diameter.
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. 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.