In an embodiment, a pair of blades, one or both of which is adapted to be reciprocated along a longitudinal axis, comprises a first blade and a second blade, each blade having a proximal end, a distal end, a length extending between the proximal end and the distal end, and a cutting edge extending along a portion of the length to the distal end. A width of each blade is stepwise reduced along the cutting edge to the distal end so that one or more teeth from the a series of teeth has a cutting surface that is receded relative to a tooth from the series of teeth that is closer to the proximal end. The teeth of the series of teeth are uniformly oriented relative to the longitudinal axis.
