Patent ID: 7297893

Claim:
A collimator for a plasma arc torch, comprising: (a) an annular holder member formed from an electrically conductive alloy and having an outer diameter with threads over a predetermined surface thereof adapted for mating with threads on an inner surface of a plasma arc torch housing, the holder member having a central bore of a predetermined diameter extending from a first end to a second end thereof; (b) an insert member formed from an electrically conductive alloy adapted to fit within the central bore of the holder member, the insert member having a longitudinally extending tubular stem portion concentrically disposed and integral with a generally circular, radially extending face-plate, the tubular stem portion having an outer diameter less than the predetermined diameter of the central bore in the holder member, whereby insertion of the tubular stem portion into the central bore of the holder member defines an annular cooling water passage therebetween; and (c) the face-plate of the insert member including an annular, rearwardly-extending flange that engages the outer diameter of the holder member at locations offset from a front surface of the face-plate whereby a joint between said flange and said holder member is contained within the housing when the holder member threads mate with the threads of the housing.