Water heater tank arrangement control device and shaft extension therefor and methods of making the same

In the method of making a combination of a water heater tank having a heating means therefor, and a control device carried by said tank and having operating means to sense the temperature of said tank and to operate said heating means in relation to said sensed temperature and a selected temperature of said control device, said control device having a housing means and having a temperature selector means rotated carried by said housing means to set said selected temperature, said selector means comprising a first knob provided with a transverse slot means therein and being the part in some applications thereof that is manually grasped by an operator for setting said selected temperature, the improvement comprising the steps of forming a shaft extension to have opposed ends one of which has drive means snap-fitted into said slot means so that said first knob is adapted to be rotated upon the turning of the other of said ends of said shaft extension, and securing a second knob to said other of said ends of said shaft extension.