Abstract: A workpiece layout tool for precisely but expeditiously marking a plurality of points to be machined along the workpiece. A slide housing has parallel internal longitudinal grooves which allow the insertion of a slide bar, allowing longitudinal movement of the slide bar in relation to said slide housing. The outside end of the slide housing has two lips which allow the slide housing to be engaged with the reference edge of the workpiece. The outer end of the slide bar has a tab on its underside which rests against the reference edge of the workpiece to maintain a fixed relationship between a plurality of spaced apart holes located along the longitudinal center line of the slide bar and the workpiece. The holes may be threaded to receive appropriate marking implements such as pencil tips, ink tips, or machined scribing tips. A multiplicity of interchangable slide bars with different hole spacing or patterns may be used according to the specific design requirements of the workpiece.