Continued
Collets were held in the quill by a compression nut on the nose - and could be had in sizes from 1/8" to 1/2" in increments of 1/32". Early collets were of the ordinary split-from-one-end type, which limited the machine's usefulness as a light-duty vertical miller, the sideways forces on the cutters causing them to work loose unless only the most judicious of cuts was taken; in what must have been a recognition of the fact that so tempting a small machine would (unless locked in a strong-room) inevitably be pressing into service for other than boring accurate holes, Linley equipped the Mk. 1A with the vastly-superior Schaublin Type ESX collet; this type had slits running from both ends and was specially designed to provided a secure grip on the shanks of small cutters.
Linley had offered a down-travel-only power-feed head as an optional extra for some time, but with the coming of the 1A it was made standard - though, no doubt, they would not have refused to sell a machine without and not all 1As may be so equipped. The feed was taken from a belt-drive arrangement within the head, via a clutch, to an enclosed gearbox which provided a drive of 0.0015" per revolution of the spindle; an automatic-disengage mechanism was included. By 1964 the feed had been modified to produce a power movement in both directions and it was this style of gearbox that was used on the improved copies built by Downham in England. In order to ease the operator's workload on boring operations the head was fitted with a very useful Direct-reading Micrometer Depth Gauge with a graduated bar passing through a boss on the side of the casting.  Its method of operation was simple: to machine to a depth of 1.167 inches the cutting tool was set in contact with the work and the bar moved until it was at any even line. The stop-screw was then lowered until it made contact with the top of the bar - and locked. The dial was set to zero, locked and then the bar lowered 11 divisions; the cut could now be made until the stop-screw was met. If the stop-screw was then released the remaining distance of 0.067" could be accurately measured by using the large and clear down-feed dial.
17.5 inches long and 7 inches wide the hardened (heat-treated) table had movements of 10 inches longitudinally and 6.5 inches laterally (a claimed 6 inches on earlier machines) whilst the maximum distance from the spindle nose to the surface was 11.5 inches.
Because the main purpose of a jig borer is to space out and machine holes with great accuracy (typically for making a holding or drilling jigs to assist in a repetitive production processes) it is important that, once the cutter has been positioned, the act of locking the table to allow the cut to take place does not cause it to move out of alignment. To this end, at some point during the production of the early machines, and in order to improve rigidity, the table ways were made slightly wider and fitted with what the makers called a "flexible-blade, non-influencing type table lock" whose function was to "prevent longitudinal movement whilst absorbing any lateral pressure from the lock screws." In other words, they admitted that the original table lock that pressed against the gib strip did move the table slightly and had been replaced by one that avoided the problem.
Because the machine was in three sections - base cabinet, knee section and main column - it was possible to introduce a distance piece between the two upper parts and so increase the spindle to table distance by around 4 inches. The sides of the table slideways were square, not dovetailed and the three T slots were 1/2" wide on the Mk. 1 and 3/8" on the Mk. 1A; the gib-strip adjustment on the Mk. 1A was simplified by the use of self-locking inserts rather than the previously-used, fiddly-to-set lock nuts; all the 'working' flat and sliding surfaces of the machine were hand-scraped to a precision fit. For a small machine the 10 tpi Acme-form, heat-treated and ground table-feed screws were huge, a full 7/8" in diameter with the zeroing micrometer dials on all three axes scaled in proportion and consequently a massive 5" in diameter; the micrometer scale was engraved around the full diameter of the handwheel, provided with a 0.0001" vernier scale and plated in a beautiful non-glare, satin-chrome finish. Although early models had comparatively tiny 2.5" micrometer diameter dials it is possible, due to the long-lasting nature of these machines, that many were retro-fitted with the later, larger versions. The movement of the feedscrews was silky-smooth and the locking mechanism - which passed through the face of each dial - held the reading without disturbing the setting; the distance between the 100 graduations on each 5-inch dial was 0.157 inches and hence accurate vernier readings could be taken without recourse to a magnifying glass; as a further aid to accurate setting-out, each table movement was fitted with a finely-engraved ruler equipped with adjustable stops.
The most important change to the machine came with the redesign of the compound table assembly; the alterations were significant (although the size of the table remained unchanged) with the saddle supported on two additional ways at the very outside edges of the knee to produce a 100% increase in bearing area. The table-to-saddle contact was also modified to improve the bearing area by over 400% - an examination of the picture here will show just how broad and strong this new arrangement was. With the outer edges of the saddle reaching to the very nearly the full width of the machine, and the saddle being heavier than the table, the effect was to give much better support to jobs when the extremes of travel had to be used; the Linley Company's rather clumsy description of this feature was ".. providing ideal balance characteristics though less lateral change in centre of gravity."
In 1964 the basic machine cost $3285 which included a motor, starting switch, wrenches and a light unit. The collets were $14.75 each, the rotary table $198, a precision machine vice $150, the step block and clamp set $40.50 and a Criterion boring bar with a collet fitting shank $70.50. A variable-speed drive unit was an additional $219.
If the prices were extrapolated to the present time (2004) then a new Linley would cost in the region of $13,500; the fact that ones in good condition can be picked up for a fraction of this indicates that here is one machine that a keen amateur, or smaller professional workshop, could well afford to consider. The Linley weighed about 800 lbs and required a floor space of 29.5" wide and 36 inches deep.
The author would be delighted to hear from anyone with Linley sales literature of any kind or a very early model that could be photographed..

A 0.5 HP motor was fastened to the back of the machine and drove forwards via a ball-bearing supported and adjustable jockey pulley to the main head by V belts. 8 speeds were provided on both Mk. 1 and Mk. 1A models of: 275, 430, 550, 860, 1250, 2125, 2500 and 4250 rpm. All the pulleys were in aluminium and were dynamically balanced. The very earliest machines had a simple guard which covered just that part of the drive belt nearest to the operator, later versions had a complete cover which hinged forwards and was restrained by a simple hinged tie bar.