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The Vernon "Combination Vertical Milling Machine & Jig Borer" was made by the Machinery Manufacturing Company of 1915 East 515T Street, Vernon, Los Angeles, California. The company used the Vernon name on a range of horizontal and vertical millers, jig borers and shapers - however, by the mid 1940s the company had either been absorbed into the Sheldon Machine Company fold, or had arranged a marketing agreement whereby the jig borer, a shaper and a horizontal miller were included in the main and subsidiary Sheldon catalogs and advertised as "Sheldon Vernon" products.
The machine appears to have been manufactured from the 1930s to the very early 1950s - and was not dissimilar in size and configuration to the contemporary American Linley of the same era. In the 1970s the design was resurrected by the Chin Tsan Machine Company of Taiwan as their Model CTV-700 - a machine with very mechanical differences and cosmetically similar even to the vertical bracing on the main column and stylised horizontal lines on the side face of the vertical head.
Like the Linley the Vernon was constructed along traditional jig-borer lines with a non-elevating compound table and the main head arranged to move up and down (over a range of 10.5 inches) on a slideway formed on the inside front surface of the main column - the aim being to produce as rigid a structure as possible. The head weighed approximately 60 lbs and was counterbalanced for ease of initial setting by a weight within the main body of the machine to which it was connected by a chain and wire. The spindle was made from a high grade alloy steel (with the collet-holding nose hardened and ground), and ran in pre-loaded, ultra-precision ball bearings with the upper and lower sets separated by a hardened and ground sleeve. The drive was taken from spindle to pulley by a six-spline shaft running in ball bearings, a design that helped isolate the spindle from drive strains. The quill, which appears to have been increased in size at some point in the machine's development from 25/8" to 3-inches in diameter, was heat treated and ground finished and operated by both fine and quick-action feeds with a micrometer-dial depth stop and a ruler fitted as standard.
The heavily-built 21" x 6" table carried 3 (7/16") T slots and had 12 inches of longitudinal and 6 inches of cross travel along a very wide knee; the maximum distance from the spindle nose to the table surface, and the maximum travel of the knee, was 10.5 inches. Unfortunately, and doubtless to the annoyance of professional machinists working against the clock, a handwheel was fitted to the longitudinal feed screw at the right-hand side only - the owner machine in the photographs below, which show the handwheel on the left, changed it to suit his personal preference. The table feed screws were supported in ball bearings where they passed through the supporting end plates and the micrometer dials were of the friction zeroing type.
The drive system was carefully though out and arranged so that the pull of the belts did not lever on the motor shaft. This was achieved by bolting a self-contained cast-iron structure to the back of the column that carried, on its lower face, a 0.5 HP 1750 rpm motor that drove upwards though a flexible coupling to an extension shaft running in upper and lower bearings held in the arms of an extension fork. The drive then went forwards via an intermediate pulley to the main head by V belts - giving a total of 8 speeds which, for the 1947 and 1948 model years, were listed as: 250, 375, 525, 775, 1250, 1850, 2700 and 4000 rpm. Efforts were made to minimise vibration from the drive system and, besides the flexible joint, all three pulleys were dynamically balanced; if a second-hand machine suffers from vibrations and rough running, it may well be that one or more of the originally pulleys has been replaced by an unbalanced replacement. The belts were guarded by a cast aluminium cover - the top section of which hinged open forwards with a clamp-shell action - styled in the "streamline" style of the 1930s. Some machines were fitted with a modified drive system that allowed a wider speed range with both step-down and step-up ratios. This was achieved by fitted two multi-step pulleys to the motor shaft extension with the upper 4-step able to drive the spindle directly or, by engaging though a pin, a small pulley beneath it that took the drive to the intermediate pulley from where it was returned through a second belt to a pulley set immediately beneath the lowest and largest of the upper set. The result was to provide both high and low-speed ranges using a system not dissimilar to that employed on the early Atlas 9-inch lathe.
It is not unusual for machines of this type to have lost some if not all of their original collet set and, because these are retained by a screwed ring on the spindle nose and not drawn in by a bar passing through the column, the range of types that can be adapted is limited. The nose was originally advertised as being designed to accept two entirely different types of collet - either an "LB" or one with a No. 7 Brown & Sharpe outside taper - in both cases with a maximum capacity of 0.5 inches. Today, either type can be reproduced by, amongst others, Hardinge in the USA or Crawfords in the UK. It is reported by current users that 3AT collets will also work - just - whilst the Brown & Sharpe 00 collet is a rather better fit, if still not an entirely perfect solution.
When the machine was to be used as a true jig borer some method better than using the feed-screw micrometer dials was necessary to position the table accurately. The contemporary solution was to fit a kit containing two 1-inch range dial-test indicators and a set of 7 very accurate rods from 1 to 4-inches in length and the necessary steel troughs into which they could be placed. Thus equipped the operator would have been able. with care, to position holes centres within fractions of one-thousandths of an inch.
The miller stood 71" high and weighed approximately 750 lbs..
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