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Parkson "Adapta" Milling Machine
Model N

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FOR SPARE PARTS for a VARIETY of PARKINSON MILLING MACHINES
CONTACT the EX-PARKINSON SERVICE ENGINEER at
collinsmrtnc@aim.com or phone: 01484-664538

Resembling, in some respects, the layout of the American Van Norman and Swedish Abene milling machines, the substantially constructed Parkson "Adapta" was intended to be a rigid yet versatile machine able to be used as both a vertical and horizontal miller. Weighing a substantial 2.2 tons (2191 kg) its makers described it as: A machine that need never stand idle when there is milling to be done - and intended the design to reduce to a minimum the amount of time spent converting from one set-up to another.
Unlike other Parkson machines that had column and foot cast as one, the Adapta had a separate, bolt-on foot, though this, in the normal way, doubled in duty as a coolant tank. Sitting on top of the column, in V-ways, was a ram-type casting able to be moved forwards and backwards through some 19" (48 mm) of travel - by a long crank handle turning rack-and-pinion gearing - with the swivelling vertical head set horizontally; with the head set vertically the horizontal travel increased to 23" (58 mm). Built into the forward section of the ram was a speed-change, oil-bath-lubricated gearbox driven (using three A-section Brammer link-type V-belts), by a 3 h.p. (2.2 kW) motor mounted on an adjustable plate towards the rear of the casting (early versions appear to have used a 2 h.p. motor). The drive emerged from the gearbox at the other side of the ram where it passed, using spiral bevel gears, into a "spindle head" that could be swivelled and locked in any position from horizontal to vertical. The head's driven gear, independently mounted on taper roller bearings, was carried on a splined drive shaft. Running in high-precision taper-roller bearings the spindle had a hardened and ground No. 40 INT nose and was held in a quill with 3" (75 mm) of fine-feed travel through the action of a screw and nut - though unfortunately there was no handy rapid-action drilling lever. 12 spindle speeds were provided, in forward and reverse, from 43 to 1000 r.p.m.
Passing through the ram casting above the gearbox, to one side of the vertical head, was a 3.75" (95 mm) round steel bar that acted as an overarm for horizontal milling when using a full-length, cutter-holding arbor.
With its drive coming from a 1 h.p. motor held on an adjustable plate within the main column, the 52" x 12.75" (1320 x 325 mm) table had three 5/8" (15.8 mm) T-slots on 2 5/8" (66.6 mm) spacing and 12 rates of feed from " to 15" (7 to 380 mm) longitudinally and in traverse and 1/8" to 6 5/8" (3 to 170 mm) vertically. Rapids drove at 90" (230 mm) per minute in the two horizontal planes and at a safer 40" (115 mm) vertically. Mechanical knock-off stops were fitted to each axis, the arrangement (and no doubt the parts) being identical to Parkinson's standard machines. Rather unusually the table's longitudinal hand-feed arrangement was by a crank handle at the left-hand end for rapid travel combined with a balanced handwheel on the right for fine adjustment - a crank also being used for the vertical feed and a balanced handle for the traverse.
One important accessory was the Sub-head - this being bolted, at right-angles, to the end of the normal vertical head and able to be swivelled thorough 360. By combining the ability of the ordinary head to be moved thorough 180, the sub-head allowed a cutter to approach a job from almost any angle, making it possible to use ordinary (and so cheaper) end-mills and slot drills to cut complex shapes. Rather cleverly, theSub-head had a tapped hole in its front face that allowed it to be supported by a brace to the overarm drop bracket.Other accessories mirrored those available for the rest of the Parkson range and included a slotting head (carried on the end of the spindle head) with a stroke adjustable up to a maximum travel of 2" and; a universal dividing head able to be driven by a train of gears from the table's left-hand end; a short lead and feed reducer; a number of rotary tables including power-driven models; ordinary and swivel-base machine vices; length rod measuring equipment and a variety of cutter holders, arbors and adaptors..
   


Parkson Adapta Mill set up for horizontal milling with arbor-support brackets in place

The knee and table assembly of the Adapta was built using contemporary Parkson design features

Milling head set vertically

Milling head set at an angle

Milling head set horizontally

One important accessory was the Sub-head. This bolted, at right-angles, to the end of the normal vertical head and could be swivelled thorough 360. By combining the ability of the ordinary head to be moved thorough 180 the sub-head allowed a cutter to approach a job from almost any angle, making it possible to use ordinary (and so cheaper) end-mills and slot drills to cut complex shapes.

Spindle horizontal with sub head inclined. Note the brace to the overarm drop bracket


Sub-head set for conventional vertical milling

A useful device for special work was the Short Lead and Feed Reducer  - shown here connected to Universal Diving Head. Bolted to the end of table (shortening the travel by around 6 inches) the device contained gears with a 20 : 1 reduction that coupled to the table feed screw. The operator was thus able to move the table with great precision, if rather slowly. However, its main use was in conjunction with the power-driven dividing head (when it allowed screw threads or spirals of short single or multiple lead to be milled when the spindle had to make a complete revolution during a relatively short longitudinal movement of the table (so making the speed of cut far too high). By providing a very slow rate of table travel (the spindle, connected by changewheels to the feed screw still rotated at the same speed) it became possible to mill threads and spirals that would otherwise have been unobtainable - the intended range of leads being between 0.1 and 2 inches.

Universal Dividing Head with tailstock and centre support. With a 6-inch centre height the unit would admit 30 inches between centres and allow work up to almost 26 inches long to be milled. Equipped as standard with a No. 10 Brown & Sharp taper (a No. 4 Morse was optional) the spindle had a through bore of 1.125"

Universal Dividing Head arranged with a changewheel drive from the table feed screw for spiral milling

Universal Dividing Head with gear-guard cover in place

2" stroke Slotting head, mounted on the end of the cutter spindle, together with the maker's tooling set

Maker's precision micrometer length rod set

Rotary Table. Two sizes were available: 10" and 14" in diameter. The 10" was made for hand-feed only but the 1`4" could be coupled to a power-feed shaft parallel to - but driven independently from - the table feed screw. Changes in the rate of rotation were made from the ordinary power-feed controls with a single lever for stop, start and reverse. It was possible to set up trips to disengage the feed and  a free rotation of the table was possible by the usual means of disengaging the worm.

Holders and protective covers for precision micrometer length rods and dial-test indicators. The length rods sat in V-shaped grooves with one end against the plunger of a dial indicator and the other against an adjustable stop.


Parkson Home Page  Parkson Page 2    Parkson Page 3   

Parkson No. 1 & 1N   Parkson M1200 and M1250
   
Manuals are available for a number of Parkson milling machines

Parkson "Adapta" Milling Machine
Model N
email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books  Accessories