Boxford and the original South Bend "9-inch" screwcutting gearboxes were mechanically identical. The picture above shows a late-type Boxford unit for metric screwcutting--note, in contrast to the English screwcutting box illustrated below, the position of the levers is reversed laterally with the diagonal line of indexing holes moved to the left-hand side.

English Screwcutting Gearbox: the diagonal line of holes is to the right. A known fault include the needle-roller bearing supported gear built into each tumbler selector arm breaking if not properly engaged (these gears are now available) and the double-gear on the shaft to which they engage (a repair is available by contacting tony@lathes.co.uk)