the shafts 12 14 of machine 10 with a desired ratio of alternating pairs of 2 mm and 4 mm wide cutting discs 16 18 fixed clearing plates 30 ride on the rotating spacer disks to ensure that any particles that are trapped between the cutting disks 16 18 are dislodged and ejected from the processing head 20 we have found that the wood particles leaving the rotary bypass shear machine 10 are broken or u201c crumbled u201d into short widths w due to induced internal tensile stress failures thus the resulting particles are of generally uniform length l along the wood grain as determined by the selected width td of the cutters 16 18 and of a uniform thickness h as determined by the veneer thickness tv but vary somewhat in width w principally associated with the microstructure and natural growth properties of the raw material species most importantly frictional and poisson forces that develop as the veneer material 20 is sheared across the grain at the cutter edges 28 tend to create end checking that greatly increases the skeletal surface areas of the particles substantial surface checking between longitudinally arrayed fibers further elaborates the l u00d7 w surfaces when the length to height ratio l h is 4 1 and particularly 2 1 or less the output of the rotary bypass shear 10 may be used as is for some conversion processes such as densified briquette and pellet manufacture gasification or thermochemical conversion however many end uses will benefit if the particles are screened into more narrow size fractions that are optimal for particular end use conversion processes in that case an appropriate stack of vibratory screens or a tubular trommel screen with progressive openings can be used to remove particles larger or smaller.