Constructions belonging to precision mechanics need to be suitable for the functional conditions. The product has to perform the task reliably in its perfection in the prescribed limit of error. At the same time this aim must be reached not at any price but economically, well manufactured and in easily marketable realization. A new construction usually becomes out of date in three-four years morally deteriorates even though if it is useful in the aspect of working. This is the explanation of the fact that the standardization and the normalization in precision mechanics play a great role. During the latest decades the polymer pieces have been appearing in the different areas of the industry. Nowadays polymer and composite materials are used not only as covering but as the material of concrete mechanical elements as they have a wide workable and usability spectrum. The pieces made of polymer materials in the telecommunication industry take an honoured place. It is because they are good insulators they are light and cheaper than the metal materials. In the European Union it is a regulation that the most of the pieces must be recyclable. It means not only the reuse of the raw material but the recycle of the pieces. So the new and economical types of connection in the polymer pieces have appeared, and their examination have become important, too. The self- tapping screwed joint is suitable, too, the economical point of view and for the recycle, as it does not need any more operations after the removal of the screw.