This application relates to a plasma torch assembly comprising a plurality of tubes; a collar integral with at least one tube comprising a first abutment surface; a base for holding the tubes during operation of the torch comprising a portion for receiving the collar and a second abutment; and co-operating interlocking portions for removably urging the first and second abutment surfaces together by relative rotation of the interlocking portions wherein the first and second abutment surfaces comprise a complimentary taper for aligning the collar in concentric formation with at least one other tube on the base by co-operation of the interlocking portions.