Carbon electrode joint

In a carbon electrode joint comprising two coaxially aligned electrode sections, each said electrode section having a threaded socket in its butt face, and a correspondingly threaded nipple joining said electrode sections in abutting relationship, the improvement which comprises having an effective amount of material removed from the non-load bearing flank of the first few threads on each side of the center thread of the nipple, the removed material having the cross-sectional configuration of an obtuse triangle extending from the root diameter of the thread to a point about three-fourths of the distance to the crest of the thread and being equal to about one-sixth of the cross-sectional area of the whole thread, the amount of removed material being sufficient to increase electrode joint strength, the number of threads on each side of the center thread of the nipple affected by removal of material being from about 18% to about 36% of the total number of threads on a single side of said nipple's center thread.