An assembly for use in a condition responsive mechanism. The assembly includes a housing part having aperture means therethrough and a control device rotatably assembled at least in part in the aperture means for selecting a set temperature of the condition responsive mechanism. The housing part has a pair of sections extending generally about at least a part of the aperture means and predeterminately spaced in off-set relation with respect to each other. The control device has a body portion formed of a generally resilient resin material and includes groove means extending thereabout for receiving in rotatable abutment the off-set sections. The groove means defines with the body portion at least one flange thereon with the flange being displaced in response to the rotatable abutment of the groove means and off-set sections so as to resile and exert a force acting to maintain the rotatable abutment between the groove means and the off-set sections.A method of assembly is also disclosed.