Founded in 1910 by Charles Kirwin, the first products of the still-surviving Illinois-based Crystal Lake Machine Works (www.crystallakegrinders.com) were designed by the owner to assist with the manufacture of reamers and plug gages (and other high-precision tools) involved in the production processes of such items as watches and typewriters. Concentrating solely on this very specialised, ultra-high-precision market Kirwin introduced, in 1936, his Universal Table-top Grinder, a machine that has survived, continuously developed and refined, into the 21st century.
Very rare, the Crystal Lake precision plain-turning bench lathe was manufactured during the 1940s and designed along the lines of contemporary, competing lathes from, for example, Stark, Ames and Pratt & Whitney. While most similar lathes had centre heights of between 3" and 5", the Crystal Lake was considerably larger at 6.5" and also able to accept 19" between centres. The lathe was also massively built with a heavy bed, cross braced diagonally between its walls and mounted on a chip pan with machined location pads. Although lathes of this type often had a bed with simple bevelled edges, or a V-way at the front and a flat at the back, the Crystal Lake chose the novel arrangement of flat at the front and a V at the back.
To ensure the greatest possible accuracy, the Company claimed that each machine was hand-fitted with its component parts mated together as a unit, calling this the Uni-fit system. However, this method was at variance with that employed by the Swiss makers Mikron and Schaublin where sub-assemblies (beds, headstocks, slides and tailstocks) were so accurately made that items drawn at random from the stores were guaranteed to align perfectly and there was no need to assemble, test and then disassemble a machine before dispatch.
Not having manufactured a lathe of this type before, the Company had obviously looked around at what else was on offer and, as the previously expensive, cumbersome and complicated drive systems offered for so many years by most others makers had disappeared, copied the much-improved offerings of Hardinge, Pratt & Whitney, Stark and Ames. Thus, the lathe was offered mounted on either an enclosed wooden underdrive stand with drawer storage in its base or on a bench top supported on three cast-iron legs - with each type holding the same heavy-duty, variable-speed drive system by "Master". The unit was driven by a choice of 2-speed, 1/2--1 h.p. or 2-speed 3/8--3/4 h.p. motors that both offered the same 18 to 1000 r.p.m. range of spindle speeds - but with the option of 80 to 1800 r.p.m. on the more powerful installation. Motors were fitted with a brake on their spindle with electrical control by a Cutler-Hammer drum switch (neatly mounted flush with the bench top to the left of the headstock) that allowed the two forward speeds to be instantly reversed. Drive to the spindle was by no fewer than three A-section V-belts (overkill, even for the 3/4 h.p. model) with the 8-inch diameter aluminium headstock pulley running in its own bearings and transmitting the drive to the spindle by a key - the system relieving the spindle of bending stresses. The top belt cover lifted off and, one most useful design point, the belts could be changed without having to dismantle the spindle. Interestingly, the choice of drive horse-power had an effect on the headstock bearings, the lower power version being fitted with Zero Timken tapers and the higher power with two New Departure Ultra-Super No. 9 Pre-loaded ball-races (4.3307 inches in diameter) at the front and one at the rear. Bored through to take 1-inch bar, the 35/8" diameter spindle was made from Max-el-1-B steel hardened and equipped (like the Pratt & Whitney 3C precision bench lathe) with a small Camlock nose in a size D-1-3" designed to take a full-size C5 collet chuck. Chucks were also offered in the form of a high-quality, steel-bodied Cushman in a 5 or 6-inch diameters and a 6-inch independent 4-jaw.
Very heavily built (it had to be to reach up to the spindle line) the carriage had a saddle locked to the bed not by the usual through-bolt but an eccentric, operated by a handle to the left of the cross slide; of course, this handy control deprived the operator of the joyful task of delving into a mass of razor sharp, oil-soaked shavings in the chip pan to release a locking wheel beneath the bed. Also of considerable proportions, the compound slide assembly featured good-sized micrometer dials, a 3/4" diameter cross-feed screw in Max-el B steel that lay in an oil bath and 360° swivelling top slide with 41/2" of travel. Unlike those on some other precision bench lathes, both top and cross slide screws were protected from swarf by being positioned beneath their respective slides.
Bored in a pair with the headstock for perfect alignment, the cam-locked tailstock held a substantial, 1 11/16" diameter, No. 2 Morse spindle that was hardened, ground, lapped to its bore and engraved with ruler graduations; locking was by a proper split barrel assembly.
Unsurprisingly, in view of its build, the machine was very heavy and the weight, 1350 lbs, just over one-half ton.