Abstract: A picking tool adapted to open a cylinder lock of the axial pin tumbler type having its tumblers arranged in a coplanar configuration, includes a planar torquing core insertable into the lock keyway in a longitudinal direction, a plurality of longitudinal guideway channels formed on opposing faces of the core, and respective tumbler probes longitudinally reciprocable in the channels. A holder, which acts as a handle for manipulating the picking tool, also serves as a housing surrounding the core and the probes. The holder is formed with a pair of radial openings in opposite sides thereof which receive respective brake segments for exerting a frictional drag on the probes. An adjustable hoop clamp surrounds the brake segments for manually adjusting the frictional drag, so that the proper tumbler displacement action can be achieved. Setscrews are threaded into the body of the holder for clamping the probes in their final tumbler-displacing positions.