Manufactured by Yun Fu Mechanical Industries Co. Ltd and marketed by the oddly named "Powerchannel Manufacturers Corporation" of P.O.Box 68-498, Taipei, Taiwan, the "Round Tower" was an exact copy of the Bridgeport Series 1 Ram-head milling machine as produced during the 1960s. Of course, this was not the only Taiwanese-built copy, many other examples have been found, sometimes bearing rather strange name badges but obviously all made by the same company and branded for distributors to sell in overseas' markets. The miller was also widely copied in Spain with, in the 1960s (and benefiting from low labour costs), up to fourteen makers turning out examples of greatly varying quality and performance.
While the contemporary British-built Bridgeport was offered in two main forms, the "9BRJ" and "12BRJ" with tables 9 and 12 inches wide respectively and 32, 36, 42 or 48 inches long, the Round Tower was listed as just a single model, its 9" x 42" table having a cross travel of 12 inches, 30 inches longitudinally and 16 inches vertically, all these being within the normal range for the genuine American machine.
Fitted with what amounted to a standard J-Type head (Bridgeport's successor to their original M-Type), its low-height "pancake" type motor was uprated to 2 h.p. and, running on a 60 Hz electricity supply, gave V-belt-driven spindle speeds of 80, 135, 210 and 325 r.p.m. in the low-speed backgear and 660, 1115, 1750 and 2750 using direct drive by V-belt.
Counterbalanced and with the standard R8 socket nose, the quill was hard-chrome plated, ground finished and had 5-inches of travel by hand feed through either a quick-action lever when drilling - or by a handwheel for fine feeds. Three rates of power down feed was fitted as standard, set at 0.0015, 0.003 and 0.006 inches per spindle revolution, worked in both directions and could be set to trip out automatically; a 0.001" graduated micrometer stop being fitted as standard. There appears to be no evidence that the Round Tower was ever offered with the later-type variable-speed Bridgeport head, the Model 2J2, with its easily-controlled, mechanically operated expanding and contracting pulley system that gave an improved speed range from 50 to 3750 rpm.
While content to offer the basic machine, it appears that the makers were disinterested in supplying a range of accessories, only a simple machine vice, an R8 collet chuck and collets and a suds pump being listed as options. This paucity of extra stands in stark contrast to the wide range of useful items listed by Bridgeport, these spanning everything from simple head raiser blocks through quick-set tooling, table power-feed units, alternative milling and slotting heads, hydraulic copying attachments, horizontal milling attachments and even oddities such as power-driven tandem rotary tables and the Polartrace, an attachment intended for the automatic production of extremely accurate two-dimensional parts made from a master between 5 and 10 times as large as the finished component. However, it may be that Yun Fu, the makers, did offer accessories, the back of the ram for example, being fitted with the fittings necessary to mount a slotting head - though perhaps this was in the expectation that a Bridgeport unit would be mounted..