The difference inherent in knives is simply due to the way they have been machined and finished."poly-master" machine knives has been manufactured over a period of 20 years of experience.a knife is not merely a piece of steel showing up a cutting edge. It is essential to find out what lies concealed behind this outer appearance which cannot be proved, until the knives-fittedinto any appropriate machine-begin to do their work. But this "intrinsical value" is determining by the machining performance each individual knife had to undergo.