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Potts Milling Spindles, Milling Column
and Tailstock Capstan Unit

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 have 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 a selection of division plates. If the latter was made, it is very rare, with only one suspected 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 alongside the unit.
In addition to the genuine Potts spindle a good number of beautifully built home-made versions have also been found - probably made 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..

Versatility. Potts spindle set up on a lathe to machine job held in a wood-collet chuck.

The high-speed collet-holding spindle is held on a rotating boss

The heads can be moved up and down the column or clamped to it with a pinch bolt

A drive pulley should be fastened to the end of the keyed shaft

Finely engraved zeroing micrometer dial

Degree graduations on the swivel boss

Acme-form feed screw with a neat, zeroing micrometer dial

Possibly a early Potts fitted with a bracket and arm to engage with a simple dividing mechanism that would have accepted changewheels from the owner's lathe.

Potts type vertical column fitted with a proper dividing attachment

What must be a "home-made" assembly complete with a high-speed milling/grinding
head with a jockey-pulley arrangement to guide the drive belt

Another well-made but non-Potts unit with both an indexing wheel and division plate

Potts Mk. 1  high-speed milling and grinding spindle with drive pulley between the bearings

Potts Mk. 2  high-speed milling and grinding spindle with overhung drive pulley

Potts Mk. 1 high-speed milling spindle mounted using the toolpost clamp on the top slide of a Myford ML10 lathe

Potts Mk. 2 high-speed spindle unit mounted on the cross slide of a Myford ML10 lathe

Potts 6-station tailstock-mounted capstan unit

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Potts Milling Spindles,
Milling Column and Tailstock Capstan Unit