Unusual in design and versatile in use the Armor horizontal and vertical "Turret" milling machine was made by the Aircraft Machinery Corporation in Burbank, California. Listed in the 1940 Burbank City Directory as Aircraft Machine Tool Co. 330 N. 1st Street, Burbank with one Jerry Robins as the manager, at some point in 1940 the Company was renamed Aircraft Machinery Corporation. Sales literature appears to indicate that this could have been a machine designed in the 1930s, and produced until at least the early 1950s - the last known instruction sheet being dated 1953.
Four models were offered: the JM, 4H, 5H and 6H; the baby of the range, the JM, was fitted with 4.125" x 16" table with 12" of longitudinal travel, 7" in traverse and 10" vertically. Differing only slightly in capacity, specification and weight the 4H and 5H were probably the most popular models - the former having a table 7" x 26" with 16" of travel while the latter, with the same 16" of travel, spanned 7" x 28" table. . The cross feed on the 4H was 7" increasing to 7.5" on the 5H and a useful 8.5" on the 6H. The 6H was a slightly larger machine, its table being 8.5" x 32" with 20" of travel
Unlike a conventional miller (but similar in design to a jig borer) the compound table did not elevate; instead, the entire head assembly - which carried a horizontal milling set up at one end and a vertical at the other - could be wound up and down a vertical slideway, this being mounted on a degree-graduated swivelling base, secured by six bolts to a substantial cast-iron housing, so that each head could be swung into position with the minimum of delay. Because each head had its own motor, and was ready for immediate use, it was often possible to leave work in place on the table and rotate the heads as they were needed; this not only minimised or eliminated the task of resetting, but also saved the time it took to transfer and remount the job on another machine.
Common to all machines was a vertical head available as the Model A without a quill feed or the Model B with 3.5" of quill travel by lever through quick-action rack-and-pinion gearing; it was driven by a V-belt from a 3-phase 1/2 hp ball-bearing motor bracketed to its side; 6 speeds were provided, from 375 to 5200 rpm, or, with the optional backgear, 8 speeds from 125 to 5200 rpm. The spindle was hardened and ground, ran in Timken taper-roller bearings and provided with a No. 7 Brown & Sharpe taper; the vertical head was not an Armor design, but built under various licences from the Ingersoll, Kearney & Trecker and the Cincinnati..
The horizontal arbor, driven from a ball-bearing motor with a final drive by either a countershaft and twin V belts (Model 4H, 1 hp), a Whitney Silent Chain (Model 5H, 1.5 hp) or a "backgear" assembly (Model 6H, 3 hp), was hardened and ground, ran in Timken taper-roller bearings and was fitted as standard with a Brown and Sharpe No. 9 taper - or, optionally, a "National". Although all models had 6 horizontal speeds, their range differed as follows: 4H: 100 to 2000 rpm; 5H 60 to 1200 rpm; 6H45 to 1450 rpm.
Longitudinal travel of the table was operated by both a hydraulic drive - with fine, rapid and reverse feeds - and a hand-operated screw thread; when using the hydraulic drive the finest feed rate was 1/8" per minute on all models, whilst the fastest varied between 150" and 180" per minute; the change from hydraulic to hand feed was by engaging a simple clutch; a micrometer stop, mounted in a T slot on the front of the table, was a standard fitting.
The tiny JM weighed 320 lbs, the 4GH 1757 lbs., the 5H 1875 lbs. and the 6H 2210 lbs..