Changes of technical characteristics of chain saws during service life

The paper presents results of the research carried out into the operating time influence on technical characteristics of motor chain saws. The research was carried out on a sample of 32 motor chain saws (16 Stihl 038 and 16 Husqvarna 266SG chain saws) in order to find out the possible changes that may occur during the four-year operation period of the saws. For that reason the tested sample included chain saws that had been in normal use for one, two, three and four years. All tested saws were used under the same operating conditions during which they had been maintained in the same way. Measurements were carried out on normal production saws randomly chosen. Previous to testing all saws were examined and adjusted in accordance with producer´s recommendations. The research has shown that there are almost no indications of significant changes of the investigated technical chain saws characteristics during normal four-year operation period. This conclusion suggestes the necessity of monitoring the main technical characteristics of the motor chain saws for a longer period of use.