Neck for a welding gun

A welding gun comprising:

• a gun assembly including a handle having a cable receiving end and also a connecting end;
• said connecting end including a tubular end fitting having female threads proximal to said connecting end;
• said end fitting also having an aperture adjacent said female threads, said aperture having a quadrilateral shape;
• a neck assembly including a body tube having a welding end and also a connecting end;
• said connecting end of said body tube being telescopically engageable with said tubular end fitting;
• said connecting end of said body tube including a circumferential, annular ring-like recess perpendicular to a longitudinal direction of said body tube and inwardly spaced from a terminus of said connecting end;
• said connecting end of said body tube also including a locking nut and male threads engageable with said female threads;
• said locking nut and male threads being disposed adjacent said annular recess away from said terminus;
• and
• a stop defined by an arcuate key circumferentially fitable in said aperture and extending into said annular recess in an assembled disposition of the gun, thereby restricting axial movement of said neck assembly relative to said gun assembly yet allowing rotational movement of said neck assembly relative to said gun assembly, said arcuate key having a quadrilateral cross-sectional shape that coincides with the shape of said aperture, said arcuate key having an arcuate shape in a radial direction that is an arc portion of a circular quadrilateral shape, said arcuate key having an outer surface that is an arc portion of a convex polygonal shape, said arcuate key having a curved inner surface that coincides in shape with said circumferential annular recess, and said arcuate key further including a curved, radially extending protrusion along and parallel to an edge of said curved inner surface, said curved inner surface of said arcuate key being inserted face-first into said aperture and said curved protrusion being positioned in said circumferential annular recess in the assembled disposition of the gun.