21 each covered with a fabric foam or soft touch material 19 an array made of multiple units of the rotating shafts as shown in fig5 6 7 a 7 b and 8 can be mounted to create an effective planar guide for the face of a knife that does minimize scratching of the blade surface steel rollers with spaced banded rings of materials or o rings as described above can be magnetized to attract and hold metal debris that is carried onto the rolling structures by the face of the contacting blade the magnetic field so established in the steel roller can attract and hold swarf left on the blade alternatively magnets can be mounted adjacent to steel rollers or bearings to attract any loose ferromagnetic debris and remove it from the roller surfaces arrays of ball bearings such as disclosed in u s pat no 5 582 535 all of the details of which are incorporated herein by reference thereto likewise lying in a plane can be used to create a planar guide surface for a blade face because ball bearings must be retained they are commonly captured in linear or circular arrays for planar knife guides linear arrays of at least three small bearings such as sold by national bearings can be arranged either running lengthwise or transverse to the long axis of a planar knife guide smaller ball bearings 24 are to be preferred as the distance between their centers provides a u201c smoother u201d surface u2014 of particular.