Bolt cutters may not be one of the more common tools found in a toolbox, but they can come to your rescue when you've forgotten the combination to your lock. Cutters vary in size -- 12 to 42 inches -- and in cutting capacity. The bolt cutter you use depends on the size and material hardness of the object you need to cut. The correct way to use bolt cutters is to fine-tune the jaws first and to keep safety in mind.

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How to Use Bolt Cutters

Preparing for the Cut

Select the correct size bolt cutter with the capacity to perform the task at hand. To cut through thin metals such as bicycle brake cables, chain-link fencing or shelving wire, shorter, regular-duty cutters are appropriate. Use longer, heavy-duty cutters to cut through objects such as thick padlocks or chains. More cutting force is generated with larger cutters.

Use caution and warn others when cutting metal objects. Metal has a tendency to snap and fly when cut. To avoid a potential injury, wrap a rag around the jaws. Note that you should never use bolt cutters to cut through live electrical circuits.

Adjust the Cutters

Adjust the jaw gap before cutting. Examine the jaw end of the tool and locate the eccentricity bolt with a hexagonal head, typically located in the middle of where the two handles join. Lay the cutter on its side so the head of the bolt faces up.

Take a crescent wrench and turn the eccentricity bolt counterclockwise. Do not remove the bolt, simply loosen it enough to loosen both halves of the tool. Bring the handles together; place a piece of paper between the jaws, and slowly turn the bolt clockwise. As you tighten the bolt, the jaws will start to come together. Stop when the cutting edges start to press against the paper. Remove the paper and check for a uniform gap between the edges.

Using the Bolt Cutters

Put on work gloves and safety glasses. Grasp the handles with both hands and hold the cutter with the jaws facing away from you. Pull the handles apart as far as possible to fully open the jaws of the cutter.

Position the middle of the cutting edges around the bolt or other object you plan to cut. The edges should be at right angles to the object. Avoid diagonal cuts because this could cause the jaws to twist and slip off the object.

Hold the handles firmly, and bring them together to apply pressure to cut through the object. If you were unsuccessful in cutting through, open the jaws slightly, position the cutting edges in the notch that was created on your first attempt, and try again. If you need more leverage, instead of using handle extensions, use a larger cutter.