The Joe Martin Foundation for Exceptional Craftsmanship Presents
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Vintage Machine Tool Collection
*G.Ve VAUCHER JEANNERET FLEURIER*, SUISSE 1866
This is a typical Swiss example of a tool used mainly by watch repairers in the 19th and early 20th centuries for working on watch plates (although some were also used in watch factories). The mechanism of a watch consists principally of a set of gearwheels and pinions pivoted between two parallel plates (or one plate and a set of “bridges” which are effectively a segmented top plate). To achieve as slim a watch as possible, some of these wheels ran in “sinks” or recesses within the plate and one use of the tool is to bore out these recesses. The exact location for the wheel centre pivot hole would be marked using a “Depthing Tool” in which the wheel and its corresponding pinion could be placed in parallel runners and set to the ideal depth of engagement by eye and feel. Then the pointed ends of the runners were used as dividers to mark intersecting arcs on the watch plate to define the exact pivot hole positions. The pointed rod running through the mandrel's headstock spindle is used to centre this pivot hole position exactly.
The second and maybe most important use of the mandrel was in repairing pivot holes and uprighting the wheels. To run true, the wheels must run exactly parallel to the plates with their pinion arbors standing vertical in the plates. If a pivot hole is worn in an old watch, it will have become oval and this uprightness will have been lost. To repair it, the hole is plugged with a brass rivet and a new hole is drilled and reamed. To get this hole in exactly the right position, one plate is held in the “dogs” on the mandrel faceplate and centered on the pivot hole using the centering rod. Now the other plate is put in place and the new hole is centered and drilled either with the tool slide or, in the case of the mandrel I use (which is and English pattern one with pulley and belt drive from the handwheel not geared drive as your Swiss one), by hand using a toolrest. This new hole will then be exactly above the one in the lower plate and so the wheel and pinion will run true and parallel to the plates. The dog clamps are, of course, spring loaded and easily movable because most of the pivot holes are dispersed about the watch plate and so this needs to run eccentrically.
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