Abstract: Apparatus for determining the internal stress within electrodeposited metals is disclosed. The apparatus includes an improved spiral contractometer wherein the spiral substrate is coupled directly to a dial indicator without the use of a gear system. A rod, passing between the dial indicator and the lower end of the spiral substrate, causes a dial indication for changes in the radius of curvature of the spiral substrate. To determine the internal stress that is created within metal electrodeposited from a particular electrolytic plating solution, the spiral contractometer is submersed in that plating solution and connected as the cathode of a galvanic cell. An anode, consisting of the type of metal being electrodeposited, is supported in a precise position relative to the spiral substrate and a constant current is supplied between the anode and the spiral contractometer for a precise period of time to electrodeposit a controlled amount of metal on the spiral substrate.