Left hand drills and bolt removers are tools commonly used to remove broken bolts or screws.

Left hand drills are drills that are designed to rotate in a counterclockwise direction, which is the opposite direction of a standard drill bit. When using a left hand drill, the goal is to drill into the center of the broken bolt or screw. As the drill rotates, it may catch on the broken bolt and begin to turn it counterclockwise, which can loosen the bolt and make it easier to remove.

If the left hand drill doesn't remove the bolt, a bolt remover can be used. A bolt remover is a tapered tool that is threaded in the opposite direction of a standard bolt. The tapered design allows the bolt remover to grip onto the inside of the bolt or screw and turn it counterclockwise, which can remove the bolt or screw from the material it's stuck in.

It's important to note that using left hand drills and bolt removers can be tricky, especially if the bolt is rusted or otherwise difficult to remove. In some cases, it may be necessary to use heat or other methods to loosen the bolt before attempting to remove it. It's also important to use the correct size and type of drill and bolt remover for the job, as using the wrong tool can damage the bolt or the surrounding material.