Generally arranged as in the pictures belwo, the apron on all lathes smaller than the 36-inch capacity machine had long and well-supported double clasp nuts (in phosphor bronze) fitted to engage the leadscrew via an over-centre, self-locking cam. A separate power shaft passed though and drove, via a keyway, a pair of pinion gears; each pinion engaged with opposite sides of a crown wheel which incorporated a simple friction device on its inner face. Because the two bevels turned the crown wheel in opposite directions the drive could be stopped, started and reversed from the front of the apron - and without stopping the lathe. The gear which drove against the bed-mounted rack could be withdrawn completely when the lathe was used for screwcutting.
The small gears and pinions used in the apron were cut from bar steel, with studs made from tool steel which had been hardened and ground.