Abstract: A manufacturing method for control devices which incorporate potentiometers whose resistance characteristics other than linearity are subject to unit-to-unit variations, and in which a wiper positioning knob in cooperation with a fixed scale indicates the set point for the controlled parameter, the method involving mounting the potentiometer in its theoretically ideal orientation in the device, affixing the knob to the potentiometer so that a pointer thereon points to the desired location on the device for a predetermined point on the scale when the wiper is positioned to control the parameter to the set point corresponding to the predetermined point on the scale, and marking the scale on the device so that the predetermined point on the scale is at its desired location on the device.