side surface and the end wall surface the function and operation of the projections 26 will be further described hereinbelow each of the fingers 18 include a guide surface 34 serving to guide a blade means into the gap or pocket formed by the platform and back portion and the fingers as noted above the fingers 18 are formed such that while extending forwardly the fingers also extend slightly downwardly as viewed in fig3 and 4 or toward the platform surface 24 referring to fig5 it will be seen that a blade means suitable for use with the above described housing includes a first blade 40 having a cutting edge 42 and a narrower second blade 44 having a cutting edge 46 the blades 40 44 being fixed to either side respectively of a spacer member 50 the spacer member 50 includes an elongated central portion 52 and end portions 54 extending forwardly of a frontal edge 56 of the central portion 52 and having outwardly facing notches 58 therein adapted to receive the projections 26 the notches 58 are defined in part by extensions 60 each having a cam surface 62 an outer surface 64 and a notch surface 66 in assembly the blade means including the first blade 40 spacer 50 and second blade 44 is inserted between.