Large self supporting Orton cones are used as witness cones in kiln. They do not require a cone support. To be precise in kiln temperature control use one cone number cone 4 below required cone temperature cone 5 and one cone above cone 6. Coned will bend gradually upon reaching nominated temperature. Do not reuse cone or in event of firing interruption in electricity supply, replace with a new cone. Note the cone react to different firing speed as in table below. Overfiring will causes cone meltdown and damage kiln shelf unless shelves are kiln wash protected.
Cone monitor kiln temperature to ensure clay body and glazes are fired to maturity. Knife makers too can know hardening, annealing and tempering temperature in oven and furnaces.