Abstract: A pattern developing tool comprising an axial pilot, pivotal bracket, and marker holder used with a retractable tape measure having a tab affixed to the zero end thereof a measured scale retractively coiled within a housing disposing a belt clip and means for locking the scale at predetermined measurements, wherein the marker holder cooperates with the tape measure belt clip, housing, and scale providing improved means for fastening a marking instrument to the tape measure housing. Said axial pilot is affixable to ferrous or non ferrous surfaces and operates to recieve the pivotal bracket adapted to fit the tape measure tab and scale, thus providing improved means for rotating the tape measure housing and marking instrument about an axis defined on the surface underlying the tape measure, permitting the user to draw accurate circles, arcs, and intersecting arcs for developing patterns on ferrous or non ferrous surfaces.