Abstract
The spiral springs for wrist-watch use, which have considerable residual stresses as the authors have already published, sometimes fail by fatigue or creep in services. The authors considered these troubles in springs should be cleared off by fatigue testing and constructed a new fatigue testing machine for spiral springs. With this fatigue testing machine, the following results were obtained. The residual stresses which were as high as 60kg/mm2 in the surface were not changed during fatigue testing of about 1000 stress repetitions. The creep of springs were considerable during two or three turns in the beginning, but after that a little creep was recognised. Lubricating oils of anti-friction were useful for elongation of service life.
