|
Although perfectly useable as a conventional watchmakers' lathe, the G.Boley F1 was really intended for specialised work involving the turning of pivots and staffs - an awkward and testing process often carried out using one hand to hold a graving tool while the other had to manipulate a hand-crank to turn the spindle.
Constructed to the highest possible mechanical standards, together with an exemplary cosmetic finish, the lathe's general layout mirrored the 1940 to 1950s development for this class of WW lathe where several makers, beginning with the English Pultra and IME and the German Leinen, stated to fit a much simpler (though more rigid) design of headstock where the drive pulley, instead of being between the bearings, was overhung on the left-hand end of the spindle. In addition, abandoning the old-fashioned separate countershaft, many of these lathes were built onto a rigid base (supported on rubber feet) that also served to hold the motor and drive system.
Designed to be exceptionally smooth running, the motor of the F1 (fitted, optionally, with a rheostat for variable-speed control) was held on a pivoting plate at the rear of the 280 mm long base unit. It was arranged to drive either directly to the pulley on the outboard end of the 8 mm bore spindle (for conventional work) or to one set lower down that turned a shaft that emerged below and to the rear of the spindle nose. On the end of the shaft was a wheel, this pressing against a larger diameter "friction wheel" mounted on an eccentric shaft set below and to the front of the spindle line. To drive the main spindle and so control the speed, a thumb-operated toggle lever was employed that moved the friction wheel against a housing formed around the spindle nose (a fitting described the makers as a "carrier disc"). The speed was regulated by arranging to set a light-to heavy-contact by a spring-actuated stop-screw that bore against the front bed way. In order to prevent damage to the work, the toggle lever was fitted with a protruding arm that - when thumb pressure was released - acted under spring pressure as a brake against the carrier disc.
When used for turning staffs and pivots the lathe was not handled in a conventional way, but operated from the tailstock end (as shown below) with the operator resting both arms on the workbench. Everything was done to make his job easy as possible with, at the back of the bed, a large height-adjustable rest for his wrist (that helped steady the right hand holding the graver on the T-rest), and the left hand positioned so that the thumb rested against the toggle lever to control the spindle rotation. In addition, not only was a fold-down flap provided under the base plate to lift the headstock end of the bed, but the whole lathe could be rotated, in its housing, along the longitudinal axis.
As the bed was a conventional 50 mm centre height WW type (and the spindle arranged to take standard 8 mm Boley collets), most accessories from the maker's watchmakers' range could be employed. Amongst these were a compound slide-rest assembly, a saw bench unit, roller filing rests, standard and reinforced-head collets, mandrel faceplate with dogs, a precision 3-jaw chuck with face jaws, hollow runners for the tailstock, a universal runner with drill pin, centring pin and associated drill holders, shellac chucks, a carrier chuck with male and female points and a Jacot drum, etc.
An experienced user of an F1 comments: "Here is an aspect of the F1 not mentioned, its capability for work between centres. Several features for this work are, I believe, unique to the model, although I am not familiar enough with the East German lathes made at the same time. The first is an eccentric tailstock to accommodate Jacot type tools that fit the universal runner. I have used these runners to burnish pivots - but, so far. I have been able to do this by setting up the universal runner at center - so I have not yet determined the benefit of this tailstock design. The other feature is the special driver attached to the headstock, via an 8mm collet body, yet turns freely when the drawbar is tight. A key engages with a rubber-rimmed driving wheel to turn the outer skirt of this fixture, a feature that I found the very useful when using the Jacot runners for burnishing pivots. I've found the slide rest to be too flexible under load for precision work and, typically, have to make three passes at each setting to reduce the load and stop flexing
If any reader has an F1, the writer would be pleased to hear from you.
Continued: Boley F1 Page 2
|
|
