A method of producing a calibrating body, gage or measuring device, preferably a screw-thread measuring device, at least partially including a C--SiC material constructed of a porous, carbon-containing material with infiltrated liquid Si, includes converting the Si at least partially to SiC by reaction with carbon. The C--SiC material is produced from a C--C material based on carbon felt material produced by pressing monofibers or fiber fragments irregularly entwined with each other. A calibrating body, gage or measuring device, preferably a screw-thread measuring device, is also provided.