Abstract: A method of manufacturing an igniting electrode for a burner in which an insulating ceramic body has a longitudinal bore therethrough with projections or teeth provided over at least part of its length, and an electrically conducting metal stem, of complementary shape to the longitudinal bore absent the projections or teeth, is forced into the bore so that the projections or teeth make an imprint in the surface of the metal stem as it is being inserted into the bore.

Abstract: A resistor built-in spark plug comprising an insulator formed therein with an axially extending bore, a terminal nut fitted in an upper end portion of the bore, a center electrode fitted in a lower end portion of the bore, a resistor arranged in a central portion of the bore, one copper-glass electrode interposed between the resistor and the terminal nut, and another copper-glass electrode interposed between the resistor and the center electrode, such resistor being made by firing (calcining) and solidifying a resistor powder mixture consisting of 30 to 10 volume % of a principal resistor component containing tin oxide, 35 to 85 volume % of insulating ceramic filler powder of a higher electric resistivity than the principal resistor component which is selected from the group consisting of quartz glass, alumina, zircon, zirconia, silica (SiO.sub.2) and .beta.-spodumene, and 35 to 5 volume % of glass powder having a softening temperature in a range between 300.degree. and 600.degree. C.