60 when the breast 18 is closed only contemporaneously with or after the flow of seed cotton into the inlet cotton chute 11 has been cut off which will result in substantially all of the seed cotton in the chute 11 being drawn up into the roll box 25 within a matter of a few seconds may the breast 18 begin the process of being drawn away from the saw cylinder 12 by the pneumatic breast cylinder 47 as best shown in fig3 the present invention 50 the seed discharge shaft 31 is defined by the distance y between the ginning ribs 26 and the elbow 61 of the seed roll retaining member 60 and the open shaft span 93 is defined by the distance z between the elbow 61 and the periphery 15 of the saw cylinder 12 the ability to manipulate or vary the width of these distances both when the breast 18 is opened and when it is closed is an essential goal of the present invention because even relatively slight adjustments to these distances can generate tremendous performance enhancement in the operation of the gin 50 and substantially reduce the loss of unginned seed cotton when the breast 18 is opened in particular the.