The screwcutting gearbox was of entirely conventional design, and supplied with a convenient one-shot lubrication system operated by a plunger on the top of the gearbox at its left-hand side.
48 standard threads could be cut on the 14", 16" and 20" MD lathes and 60 on the 20" HD - without having to change or add any gears to the quadrant arm.
Extra gears were available to cut metric, diametral and modular pitches and there were two special ranges of gears available to produced threads of finer and coarser pitch than standard. The one useful thread missing from all the charts was 19 tpi.
The leadscrew was used only to generate threads, the power sliding and surfacing feeds being provided by a feed shaft,  engaged by a small lever on the boss formed where the shafts entered the gearbox on its right-hand side.
The direction of the carriage movement could be reversed by a lever, operating a double bevel within the apron, without stopping the lathe or having to reverse the direction of rotation of the feed rod. The operation of the headstock clutch and spindle brake could also be controlled from the apron - as well as from the headstock.