An adjustable switching mechanism for adjusting the tolerance of electrical contacts of series coupled vacuum interrupters includes a primary drawbar coupled to a secondary drawbar via a pair of coupling pull rods. The primary and secondary drawbars are adjustably attached to the coupling pull rods by a plurality of adjustable compression assemblies. The primary drawbar also includes an attachment bore having threads of one dimension to threadably receive a double-threaded part therethrough. The double-threaded part also includes an internal bore having threads of another dimension in which to receive a coupling screw. As such, the tolerance between the electrical contacts of the vacuum interrupters may be changed through adjustment of the compression assemblies and the rotation of the double-threaded part.