Very unusual for its size in having a miniature, Deckel-like double-swivel table that could be both tilted left and right and swung through an arc horizontally, the Sloan & Chace bench milling machine was of the highest quality. Also similar in concept to the pre-WW2 Schaublin SV11 and SV12 precision universal milling machines, this was a compact but heavy (308 lb) model intended for tool-room, experimental and light-production work. It was available as either the "No. 2" - with a conventional, non-swivel table that was driven longitudinally a quick-action rack-and-pinion gearing and across by a screw - or as the "No. 3", a special toolroom model (illustrated below) with a swivelling and angling table. The internals of the "spindle-head" assembly would almost certainly have come, unmodified, from the company's "No. 5 1/2" bench lathe, the makers explaining that work could be transferred in a collet, or mounted on a faceplate, from the lathe to milling machine and back again without the need to disturb its setting. Hardened and ground, the spindle ran in split, parallel-bore cast iron bearings fitted into tapered sleeves with threads on one end. By turning adjuster nuts the sleeves could be drawn into the headstock and so compressed to set the bearing clearance. To adjust the spindle end float an adjustable collar, of hardened steel, was screwed into the end of the 3-step cast-iron pulley and bore against the inside face of the front spindle bearing - the thrust being taken against the inboard face of the spindle-thread abutment shoulder.
Although a useful size at 22" long and about 4" wide, it was here that the distinctive twin inverted V-ways of the company's lathe beds put them at a disadvantage for, while all their competitors could offer small millers with tables formed to the same simple cross section as their lathe beds (with a flat top and bevelled edges) Sloan & Chace could not. This meant that unlike the others, where it was possible to transfer all the special, and in some cases very expensive accessories, straight from lathe to miller (or visa versa) and so save a considerable amount of money, with the Sloan & Chace special adaptor plates (that reduced the machine's vertical capacity) had to be purchased. The table had 10" of longitudinal travel, 4.75" in traverse and 7" vertically; the micrometer dials could be zeroed and were engraved to show table travel in increments of 0.001". The vertical feed to the knee was operated by a handle at the rear of the main body and worked through a pair of bevel gears and a screw thread.
The principle of a swivelling and angling table as used on the No. 3 Sloan & Chase was eventually to be used and further developed by a number of makers (over thirty at the last count), notably the German Deckel Company (with what was to become their best-selling range of FP milling machine) with other early and prominent exponents being Thiel, Maho and Schaublin.
If any reader has Sloan & Chace milling machine, the writer would be interested to hear from you.
Pictures of the Sloan & Chase milling machine continued here