email: tony@lathes.co.uk
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Sajo Milling Machine Model 54 - Sweden

Sajo Models 53 & UF44   Sajo VF54 Vertical & Duo Mill Vertical   

Sajo UF48, UF48P, PF49P   Sajo UF52, PF52, Duo Mill 52, VF52  APF52

Sajo Manuals and Catalogues available here

Sold during the 1950s and 1960s, the Model 54 was built in Mk. 1 and Mk. 2 versions and as the Type PF54 Plain Horizontal , Type UF54 Universal with swivelling table , the Duo Mill 54 with a self-powered "Toolmakers" overarm, the Type 54 Vertical with and without power down feed to the quill (also offered with automatic table cycling) and the production millers Types APF Plain and AVF54. Easily identified, the Mk. 1 had a dovetail-fitting overarm triangular in side elevation section with a much greater depth in the centre - while on the Mk. 2 this difference was greatly reduced and the arm flatter. On the Mk. 1 the knee had a shallow return angle to the lower front face of its, this being noticeably increased on the Mk. 2
Both versions of the Model 54 were built around a substantial column casting formed as one piece with a heavy foot that doubled as a coolant tank. Inside the foot, ribbing increased its rigidity and was utilised as swarf settling traps. A door on the right-hand side of the column gave access to the electrical system (with a plug provided for an extra-cost light unit) with, at the back of the column, a hinged door to cover the 6 h.p.motor (7 or optionally 5 h.p. on the Mk.2) - both driving, using six V-belts, direct to the spindle speed-change gearbox. With the motor mounted on an adjustable plate, to adjust the belt tension, an external handwheel was provided at the bottom of the column's left-hand face.
The Sajo 54 was offered in both Plain Horizontal and "Universal" types, the latter having a table that could be swing on its vertical axis by up to 45 on each side of central. Following the example of Cincinnati mailers dating from the late 1930s, control of spindle speeds was by a large dial set on the left-hand face of the column; one movement of the crank handle fitted to the dial selected the next higher or lower spindle speed - of which sixteen reversible ones were available that spanned either 39 to 1500 r.p.m. or, optionally, 31 to 1200 r.p.m. Electrical control of the miller's spindle drive was by a triple-function lever - mounted on the left of the column and adjustable for position - that gave a start, stop and brake function, the latter by applying gentle pressure in the stop position.
Fitted with a No. 50 INT nose that was hardened inside and out and machined from a chrome-nickel steel forging, the spindle ran, of course, in a high-class grade of Swedish-made SKF bearings. At the nose, a staggered, double-row cylindrical roller took radial loads, two ball thrust bearings immediately behind absorbed axial thrust and, supporting it at the other end, was a single cylindrical bearing Fitted with provision for adjustment, the bearings were all of the "SP" -special precision - type. Inside the main column, the speed-change gears were all in the very best grade of "Bofors" alloy steels and hardened and ground (or shaved) for their particular function. All the gear-carrying shafts ran in SKF anti-friction bearings with lubrication a pressure pump.
One inch (25 mm) in diameter, the cutter-holding arbor was a precision ground forging of nickel-chrome steel and carried a set of lapped spacers; it was supported at its outer end in a single drop arm fitted with an adjustable bronze bush that was oiled from wicks dipping into a reservoir held within the overarm. Of the dovetail type, the overarm was cored from one end only to provide an unbroken and hence twist-resistant tubular section; its slides were precision ground to fit into the hand-scraped slides on top of the main column turret.

Heavily built as a box-section casting, the knee was internally ribbed for extra strength and housed, flanged mounted to the left-hand face, a 1.5 h.p. table-feed motor, Built into the knee was a feed-rate-change gearbox with lubrication by splash from a sump. Long, hand-scraped ways were used with tapered gib strips to take up play and, to protect against the ingress of swarf and dirt, the top of the knee was fitted with telescopic metal plates - and the knee and column bearing surfaces covered by fabric aprons. 
1200 mm long and 280 mm wide on the Mk.1 (1320 mm by 280 mm on the Mk.2) the table carried three 18 mm T-slots spaced 70 mm apart and all-around coolant troughs. Fitted with a single handwheel at its left-hand end - and a large-diameter, satin-chrome plated micrometer dial - the table's longitudinal feed screw ran through a two-part, bronze nut that was adjustable from a screw on the face of the saddle. This provision aimed to make available an immediate elimination of backlash - and so help with climb milling. Under power, travel longitudinally was 850 mm, in traverse 300 mm (but only 250 mm on the Mk.1) and vertically 455 mm. Twelve rates of table and knee feed were available, these ranging from 18 to 635 mm per minute longitudinally and in traverse and at half that rate vertically - the rate required being selected by a capstan handwheel on the front of the knee. Each feed was operated by a separate lever, the direction of travel being the same as that of the lever. Rapid feeds were available in all three directions, at 2400 mm per minute longitudinally and in traverse and at half that rate vertically, the usual type of control for this being provided by a long, spring-loaded lever pivoting from the right-hand side of the knee that, when released, stopped the travel.
Lubrication of the table ways and drive mechanism was by a one-shot system, the plunger for which was placed clearly in view on the front of the saddle. If, after two hours of running, the oiling system was not activated, the operator received a violent electric shock as a reminder; I'm only kidding, to see if you're paying attention...
Coolant equipment was part of the standard specification, the geared pump being driven by a V-belt from the main motor.
A range of accessories was available including a changewheel-driven dividing attachment for the Universal Model, rotary tables, a slotting attachment, machine vices and two vertical heads - one a swivelling type mounted on the horizontal spindle flange, the other carried on a horizontal shaft support by the drop bracket.
Standing 1625 mm high,  1771 mm across the full extent of the table and its handwheel and 1564 mm from front to back, the Sajo Model 54 Mk. 1 weighed approximately 1850 kg and the Mk. 2 1950 kg.

Sajo Manuals and Catalogues available here

Sajo Models 53 & UF44   Sajo VF54 Vertical & Duo Mill Vertical   

Sajo UF48, UF48P, PF49P   Sajo UF52, PF52, Duo Mill 52, VF52  APF52

- this section under development -
Sajo Milling Machine Model 54 - Sweden
email: tony@lathes.co.uk
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