Alternating charge clusters of side chains: new surface structural invariants observed in calf eye lens gamma-crystallins

A cutter wheel for a brush chipper or the like has a support plate generally centered on, extending perpendicular to, and rotatable in a predetermined rotational sense about a central support axis. This plate is formed with a plurality of slots angularly equispaced about and radially equispaced from the support axis and with a plurality of screw holes each trailing a respective slot relative to the rotational sense. A plurality of blades each have an annular outer periphery formed as a succession of cutting edges. The outer peripheries of the blades are centered on respective blade axes and each blade has at the respective blade axis a throughgoing attachment hole. Respective attachment screws engage through the attachment holes with the screw holes, with one of the cutting edges directed forwardly in the rotational sense of the support plate. Thus with this system a new cutting edge can be brought up simply by loosening the respective screw and rotating the blade, then tightening the screw.