A resistance welding gun is provided that includes an arm assembly having spaced apart plates. First and second spaced apart blocks interconnect the plates and extend between the plates in a first direction. The first and second blocks are machined to provide a desired spacing between the plates. An electrode arm is arranged between the plates and blocks and supports an electrode end having a replaceable cap in one example. A clamping device applies a clamping load in a second direction transverse to the first direction to secure the electrode arm between the blocks. Lateral alignment between opposing electrode ends is achieved by a movable adjustment assembly on one of the arm assemblies. A pivot pin interconnects the block and electrode arm for permitting rotation of the electrode arm relative to the block. In one example, the adjustment assembly includes an adjustment member that is rotated to laterally move the electrode arm about the pivot pin in a desired position.