During the 1940s and 1950s, the G.P. Potts Company, based in Troutbeck, Windermere, was best known for three versions of their beautifully made, column-type high-speed milling and grinding unit. The company also manufactured a range of independent high-speed milling heads intended to be mounted on the top slide of small lathes to assist with more complex milling operations, gear-cutting and ornamental turning. They also produced a six-station capstan head, fitted with a Morse taper arbor and used in a lathe's tailstock.
With their spindles running in hardened bearings, two of the three column attachments were designed to mount on a hinged bracket (that allowed them to be used for milling and toolpost grinding) while the third was as built as an integral part of a milling slide. The latter type consisted of a 1.75" diameter column some 6.5" long (intended to be secured to a lathe's cross slide) with the spindle assembly able to be moved up and down through a range of 3.75" and also swivelled. A feed-screw of Acme form was fitted, complete with a finely-engraved bevelled-faced zeroing micrometer dial - and the rotating part of the head marked with similarly-clear degree graduations. The milling column might also, originally, have been intended to carry a simple dividing attachment fitted with changewheels taken from the owner's lathe, or as a proper dividing attachment with an overarm and a selection of division plates. If the latter was made, it is very rare, with only one example being found in recent times. It was also possible to mount a high-speed milling spindle, powered from on "overhead" (often a complicated and expensive drive system arranged above the lathe) but today more easily driven from a small motor carried on a bracket attached to the head.
In addition to the genuine Potts spindle, a good number of beautifully built home-made versions have also been found - probably made from commercial kits, or when the toolroom was either less busy or, surreptitiously, on the night shift ….
Shown towards the bottom of the page are two long-popular, sought-after independent high-speed heads for use on a lathe's top slide. Available with the pulley positioned between the bearings (as the Mk. 1) or overhung (Mk. 2), each was supplied with three 8 mm draw-in collets and a plastic-handled drawbar. Potts also offered a well-made 7" x 4.5" saw table designed to mount on the bed of almost any small lathe (at £3 : 10s : 0d finished or 16 shillings for the castings in 1949) and also a special version of the milling spindle designed to clamp around the post that was cast as an integral part of the top slide on the Myford/Drumming M-Type lathe - a fitting normally used to mount the Norman Patent height-adjustable toolpost..