Self centering electrode joint

A carbon electrode joint comprising a pair of opposed abutting carbon electrode sections each section having respective opposed threaded sockets, with each said threaded socket having threaded grooves separated by substantially flat surfaced crests and a threaded carbon nipple having:

• (i) a longitudinally extending root portion;
• (ii) spaced apart threads on said root portion extending outward therefrom and integral therewith threadably engaging threaded grooves of both electrode sections;
• (iii) an abradable ridge on said root portion integral therewith located adjacently intermediate said spaced apart threads on said root portion and extending outward from said root portion but to a substantially less extent than said spaced apart threads so that upon threadable engagement of said threaded carbon nipple with a carbon electrode section, said ridge is abradably worn away and bears against the flat surfaced crests of the threaded socket which separate the grooves of said electrode section socket to provide a flat surface on said ridge which bears against the flat surfaced socket crests.

As an article of manufacture, a threaded carbon nipple for joining a pair of opposed carbon electrode sections each having respective opposed threaded sockets, each said threaded socket having threaded grooves separated by substantially flat surfaced crests, said threaded carbon nipple comprising

• (i) a longitudinally extending root portion;
• (ii) spaced apart threads on said root portion extending outward therefrom and integral therewith for threadably engaging threaded grooves of an electrode section;
• (iii) an abradable ridge on said root portion integral therewith located adjacently intermediate said spaced apart threads on said root portion and spaced away from adjacent threads on said root and extending outward from said root portion but to a substantially less extent than said spaced apart threads so that upon threadable engagement of said threaded carbon nipple with an electrode section said ridge is abradably worn away to leave a flat surface which bears against the flat surfaced crests of the threaded socket which separate the grooves of said electrode section socket said ridge is being slightly closer to one adjacent thread so that it will abradably bear against the central portion of a flat surfaced crest of the socket of an electrode section.