Presented diploma thesis is concerned on increasing tool lifetime by applicating coating on wood machining cutting tools e.g. planer knives that are used for wood wool machining. The Main goal of presented thesis is examination of increasing tool life on planer knife with CrN/TiN coating on both sides of the cutting edge during machining coniferous species C-class grade. In the introduction of teoretical part there are described and charakterize tool materials used in current state for manufacturing wood machining tools used in wood machining industries. In further part there are described methods of creating coatings on surfaces of materials and methods are comparise in each other. After that in the end of theoretical part there are characterized testing methods for testing coating features as are Calotest, Mercedes test and ball-on-disc test. Experimental part consist of entering tests, which we get charakterize features as si hardness and adhezive attribute on tool with coating. In further chapter presented thesis is dedicated to practical experiment and their results. In the end of practical part there are interpretation of this results in respect of quality. and recommandations for the future research in this field.