Could you build a small but practical lathe in a day - one good enough to be used to help with the building of sub-miniature, 2 mm Scale, N and (to some extent) HO/OO gauge model railway engines and rolling stock ? That was the challenge Dr. Peter Clark set himself at an early 1990s IMREX show (International Model Railway Exhibition, run by The Model Railway Club). Starting before the morning coffee break, he laboured steadily at the task through the day - having, needless to say, to fend off countless interruptions as the deadline drew nearer. The maker would be the first to acknowledge that, in accepting the challenge, he was cautious enough to take along some prepared materials - and to have built a drilling machine along similar lines beforehand - nevertheless, this was a considerable challenge and it speaks volumes for Peter's skill and ingenuity that, not only was he able to complete the task in time, but also produce a lathe that has proved entirely practical and well able to fulfil its design criteria.
The lathe's basis of operation is a method of "assisted" hand-graving (first suggested in a sales brochure by Lorch, a German maker of watchmaker's lathes) where a finely-finished and very smooth steel plate provides a surface on which a small toolholder, with a flat base, can be manipulated*.
The design and layout of the lathe can clearly seen in Fig. 1 - a Dremel or Minicraft style high-speed drill, with a standard chuck, is clamped in wooden stocks and provides the headstock assembly. Small drill chucks are perfectly adequate for this task - and even on larger lathes can be usefully employed for holding very small parts.
A steel plate is screwed to the 280 mm x 100 mm plywood base and provided with a strip of steel along one edge to act as an abutment against which the drilling tailstock - shown in place in Fig.1 - can be guided.
All turning is done by hand - either completely freely, as in Fig.2, or against an adjustable, angled support bracket (Figs.1, 3 7 4).
A form of simple tailstock (Fig.9) can also be employed, as can a drilling tailstock (Figs. 7 & 8) whose movement is controlled either by hand or a simple lever pivoting on a pin inserted in one of several holes drilled in the guide plate.
Besides the main lathe, it is also possible to construct a surprisingly wide range of effective accessories - a fixed steady, locomotive frame drilling unit and sanding and grinding tables, etc.
If you would like to build one of these lathes - a weekend should be sufficient, including shopping for the simple materials required - there is an excellent article by Nigel Cliffe of the 2 mm Association, which explains the process in detail.
Peter has also used this technique on Cowells and Clisby lathes - and in the case of the latter miniature machine has added both some interesting accessories and well-thought out improvements to the original design./