Image Number 2 for United States Patent #4633592.
A precision rule having a handle part, preferably of aluminum, a holding part, preferably of a hardened steel and a rail embedded in a longitudinal groove of the holding part having a measuring edge, preferably of a hard metal. The handle part and the holding part are connected to one another by the interpositioning of O-rings and screws such that a space which forms a temperature barrier is created. The screw shanks extend loosely in the handle part. With this form of precision rule, any heat influence on the measuring edge through unavoidable external heat sources, for example the heat of hands, is avoided even during longer working times, and is achieved by the provision of built-in heat barriers.