Thomson Houston First Electric Butt Welding Machine, c. 1886, accessories: 2 pieces of 2" x 5/8" steel prepared for welding; 2 pieces of 2"x 5/8" steel welded, as from machine; 2 pieces of 2"x 5/8" steel showing perfect weld after being dressed; 2 pieces of 2"x 5/8" steel welded and twisted

This is one of the earliest resistance welding machines made by the Electric Welding Company under Elihu Thomson's patents of 1 886. Parts up to 3 square inches in section could be welded and the maximum power expenditure was 40 Kw. The apparatus comprises a transformer, powerful screw clamps to hold the work; and a lever, ratchet, and screw mechanism for forcing the parts together. There is provision for water cooling