Rockford did not just make small bench and stand millers, their "No. 1 Horizontal Plain" of 1912 was a very strongly built machine which incorporated a number of carefully thought out features to assist the operator.
With a working surface of 38" x 9" the table had 24" of movement horizontally (with automatic safety stops), 7.5" in traverse and 19" vertically. The 4 to 1 ratio backgeared main spindle with its B & S No. 10 taper, ran on adjustable, tapered bronze bearings (fitted with felt oil retainers) and was driven from a two-speed countershaft by a 2.5" wide flat belt acting on a 4-step pulley; this arrangement provided 16 speeds, normally from 22 to a rather slow maximum of 309 rpm.
Well designed and, for its day, unusual in being neatly built and safely enclosed, the table power feed arrangement was by a chain that took the drive down from the inside of the main spindle though an enclosed channel to a 14-speed gearbox mounted inside the machine's main column. The box was built with steel gears held on shafts running in bronze bearings and could be operated whilst the machine was running; an external reversing box was fitted to the universally-joined, telescopic table feed shaft.
The machine's distinguishing feature was the overarm arrangement; from the earliest days horizontal millers had been designed, or adapted, to accept vertical milling and slotting heads which plugged into, and were driven from, the horizontal spindle; unfortunately, this usually involved loosing a great deal of the machine's capacity - the distance from the table to the cutter being far too short. The Rockford miller overcame this problem in an ingenious way - the drive from the spindle was lifted by gears so as to pass through a hollow overarm support. This immediately improved the maximum thickness of the workpiece that could be held on the table and allowed the construction of a large clamping area to improve the rigidity of the fixing. With a little more thought, a set of interchangeable drive gears could also have been provided - and so doubled or even tripled the speed range.