Bolt cutters are an all around great tool for any homeowner or professional builder to own. They allow you to quickly and easily cut through metal pipes or chains without the noise or danger of using a saw or grinder. Bolt cutters are designed with a special bolt in the head, called an "eccentricity bolt," to allow you to adjust the bolt cutters and keep the required tension on the blades.
Lay your bolt cutters on their side so that the black hexagonal top of the eccentricity bolt is facing up. This bolt is the middle bolt located at the base of the head of the bolt cutters where the handles join.
Loosen the eccentricity bolt using a crescent wrench to turn it counter-clockwise. Do not remove the bolt, just loosen it enough for the two halves of the jaws of the bolt cutter to become loose as well.
Hold the handles of your bolt cutters shut. Place a sheet of paper between the jaws of the bolt cutters and tighten the eccentricity bolt by turning it clockwise until the jaws just begin to press into the paper.
Check the adjustment on your bolt cutters before you use them. This will save you the frustration of trying to make a cut and having to stop and make adjustments to the tension on the bolt cutters.
Use care when adjusting bolt cutters; while the blades are not exceptionally sharp, the force of the jaws closing can easily cut off your fingers.