The Dawson Kiln Sitter firing gauge is a small metal disk used to adjust the Kiln Sitter actuating rod.
Many people have never seen a firing gauge, because it is often thrown away. But the gauge is important. If you don’t have one and your kiln has a Dawson Kiln Sitter, you should order the firing gauge. The cost is only $4.75 plus shipping. Your ceramic supplier may have them in stock.
A firing gauge comes with every new kiln equipped with a Kiln Sitter. Do not fire the kiln with the gauge on the cone supports. The gauge would prevent the Kiln Sitter from shutting off.
Use the gauge to adjust the actuating rod after every dozen or so firings. Place the gauge on the cone supports, sliding the actuating rod through the hole in the gauge. If the actuating rod is not centered in the porcelain tube, loosen the two screws on the guide plate and move the guide plate from side to side.
Lift the Kiln Sitter weight to the raised position. With the firing gauge in place, the trigger should just barely clear the release claw, coming as close as possible without touching. If the gap is wrong, loosen the set screw in the center of the weight, move the trigger and retighten the set screw.