|Typical cut running pliers|
Cut running pliers are very useful tools if used correctly. The pliers must have the curve in a “frown” rather than a “smile” to operate properly. The knurled screw at the top and the scored line on the top jaw help place the pliers the right way up. They must be placed directly in line with the score. They should be only a centimetre or so onto the glass. Holding them at the end of the handles, apply gently increasing pressure until you hear a click or see the score running. If it does not run completely, turn the glass around and apply the pliers to the other end of the score.
Use of the Adjustment Screw
It is important to make use of the adjustment screw to get the best from the pliers. If this is not adjusted properly, it is possible to crush the glass, or at the other extreme, not run the score at all.
The jaws need to be adjusted for the thickness of the glass. The method I use for this is to place the edge of the runners on a corner of the glass to be scored.
Loosen the screw until the glass is gripped by the jaws.
Gradually tighten the screw until it resists your gentle pressure on the handles. This gives you the correct opening of the jaws for that piece of glass.
When the pliers are properly adjusted to the thickness of the glass, you will not crush the glass and it is easy to use the pliers without cushions.