The taper thread gauges for graphite electrode are used for general calibration of electrodes and nipples, normally there are taper working gauges and master gauges.

Two taper working plug gauges are used for calibrating electrodes, three taper working ring gages are used for calibrating nipples. One master ring gauges are used for calibrating working plug gauges, one master plug gauges are used for calibrating working ring gauges, there 7pcs gauges for one size graphite electrode.

Taper thread gauges catalog for graphite electrodes(English Version)