Almost certainly made from the late 1940s into the 1950s, the WA-CO miniature high-speed drill was manufactured by a now long-forgotten Company, Precision Tools Ltd. who occupied premises at 100 Chamberlayne Road, London N.W.10.  Although built with a modest shop-like front, viewed from above it is clear that the current building stretches back a considerable distance and would have provided ample space for small-scale manufacturing. If Precision Tools made any other engineering equipment is not known, though it is doubtful if just one model of drill press could have sustained a profitable enterprise...
A tiny machine, standing 11 inches (280 mm) high, just under 8 inches front to back (200 mm), 3.25 inches wide (83 mm) and weighing just 3 lbs, the WA-CO was constructed along the lines of the older "swan-neck" type - as made in smaller versions by companies such as Denbigh. It was designed expressly to drill holes smaller than 5./64" (2 mm) - that being the capacity limit of the chuck as well as the optional collet fitting.  Power came from a "Universal" (A.C.-D.C.) 200/220. 220/240 and 110-volt, 1/30 h.p., 18,000 r.p.m. motor held on a round boss at the rear of the column and adjustable along it for belt tension - the on/off switch being attached to the motor body.  Rather unusually, the drive was covered with a transparent guard in plastic - surely a unique feature on any sort of drill. The drive passed over three-step pulleys that gave spindle speeds of 7,500, 8750 and 10,000 r.p.m. with the belt used being either a "rubber impregnated" V-type or, for use with very small drills, a recommended "wire" version. Down-feed - through a range of just one inch - was arranged very simply by a fulcrum lever that engaged with a collar on the spindle between the upper and lower bearings - a system also used on small tapping machines. Depth control was simple and direct, a knurled-edged ring running on a threaded section at the upper end of the spindle and hence able to be adjusted to a precise setting as it abutted against the top of the main casting
Of much heavier construction than the very light, small drill presses made for amateur use by such as Champion - where the motor was fastened to the bench at the back with the drive, by a round leather rope-passing over a pair of jockey pulleys to guide it around the spindle -  the WA-CO was a serious effort aimed at such as jewellers, watch and clock makers and instrument repairers. In nearly all respects, therefore, for that type of user, it would have been preferable to the very heavy, much larger and more expensive, industrial-class high-speed bench types offered by such as Jones & Shipman and Pollard.
It was also possible to order the drill in gangs of from two to six mounted together on a ground-surface, cast-iron base - the assembly allowing, for example, the drills to be equipped with bits of different diameter to speed up a production process.
Obviously proud of the product, the makers described it in glowing terms as: "A brilliantly conceived engineering job...exquisite accuracy...sensitive...light...robust...reliable...compact...vibrationless. A possible competitor for Precision Tools Ltd. was another London company,  Engineering Products Ltd., who made the interesting Oldak and Apex drilling and tapping machines. A drill very similar to WA-CO was the mysterious Ruka, though this differed in having a swivelling and tilting table - but  just a single pulley on the spindle and drive by a remotely-mounted motor.
If you have a WA-CO drill, the writer would be interested to hear from you.