Abstract: A two-part worm drive clamp embodying a first part in the form of a tensioning strip having a housing-enclosed, slack take-up worm at one end and a tab at its other end, and a second part in the form of a ribbon-like, band-forming strip having a tab-receiving cut-out or opening at one end and a longitudinal series of generally transverse, worm-engaging slots extending inwardly from its other end. The desired size of the clamp is attained by wresting the second part from a tandem or one-in-front-of-the-other array of unit band lengths in a roll of preformed band-forming stock, the requisite number of unit lengths being dependent upon the required size of the band of the clamp. An important feature of the invention resides in the nature of the interlock which is established between the tab and the tab-receiving opening, the interlock being such that it is unnecessary angularly to displace either part in order either to effect or disconnect the interlock.