Executed system analysis of the types of damage to logging machines and damage them in the manufacture. It is found that defects in material, shape and size of the part have a significant impact on the reliability of the equipment. The main attention is paid to the effect of crack-like defects. If as a measure of damage to take the length of the crack and apply the methods of fracture mechanics in the calculations, it will be obvious the relationship of operational and industrial damage. It is established that the main cause of failures of logging machine details of domestic production is not enough high quality of their production. It is recommended to use more widely such as characteristic of materials as fracture toughness to assess the reliability of the design.

Keywords: Logging machine, reliability, damage, manufacturing defects, fracture toughness