A tool for temporarily immobilizing and holding a cable clamp in an electrical box, so that a locknut can be more easily threaded onto the clamp. The tool has a front fork portion with two prongs and a rearwardly tapering space defined between the two prongs, and a back portion with a formed handle that tapers to a rounded end. The front and back portions are substantially flat and integrally formed. Two tools for varying sizes of cable clamps can be provided, preferably rivet-hinged together at their handle ends.