The Stalwart 3" x 18" lathe was typical of the products of smaller machine-tool makers during the first three decades of the 1900s and the makers, Cryer and Dawson of Bingley, England, offered a range of extra to convert the lathe to a full screwcutting model. Backgear appears to have been fitted as standard with the engagement by the usual type of eccentric shaft.
A large section of bed could be removed to create a gap and, to ensure that the cutting tool was able to reach across to the faceplate, not only was the cross slide was set to the far left-hand edge of the long-armed saddle but the swivelling top slide projected well forwards in advance of its locating point - both features that were unlikely to have engender tool rigidity and chatter-free turning.
If anyone knows where a Stalwart lathe might be found, the grandson of Mr Cryer would be delighted to hear from you