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The Visitor 6
Watches take shape


Here, at last, the watches begin to take shape, but before passing to the assembly stage, the visitor will be shown one of the high-spots of modern watch manufacture, the Greiner Spiromatic hairspring vibrating machine, which gives the correct count to the balance and hair-spring assemblies. The action of the machine is almost uncanny, for it will unfailingly find the correct pinning point for the hairspring in a few seconds. All the operator has to do is to feed its two timing heads with balance-and-hairspring assemblies by slipping the outer end of the hairspring past a counting pin and then on between a spring-loaded pressure roller and a knurled feed shaft. The Spiromatic then takes over, and, under the control of a quartz crystal time standard, it checks the time of swing of the balance and spring and automatically winds in or out the outer coil of the spring until the right point for correct timekeeping is reached. At that moment, the alteration of spring length ceases, and a stroboscopic indication is given that the adjustment has been completed. The other timing head, which has been loaded during the operation of the first, is now, in its turn, brought into operation whilst the operator cuts off the timed spring to length by pressing a cutting lever that also pre-shapes the outer coil for pinning. This alternate operation of the two heads of the machine enables about 200 balance assemblies to be timed in an hour.
The Assembly Line
Just beyond this machine is the beginning of the assembly line, which is probably one of the best laid out in any watch factory in the world. As usual, the assemblers sit at benches arranged at right angles to the direction of travel of the central conveyor belt. The benches are so well fitted that they would be the envy of many craftsmen, and a notable feature of their construction is the cunningly angled arm rests. 


10 1/2 ligne gents wristwatch assembly

AssemblyAssembly proceeds on what is known as the "sequential batch" method, the average batch being 50 movements. Everything is done to simplify each process, and a number of clever tools and fixtures have been provided to assist with this. Supplies of parts are held in containers which are arranged in nests facing the assembler, and the addition of each component during the assembly process is carried out with a minimum of movement and effort. Movement assembly follows normal lines, the plate receiving its train, bridges, escapement, and so on, in stages as it moves along from assembler to assembler, between each process the movements are placed in individual containers for their brief journey to the next assembler and placed on the conveyor. Barriers spanning the conveyor belt halt these containers at the appropriate point, and after completing her stage of assembly, all that each girl has to do is to replace the movement in its container and put it back on the conveyor on the other side of her particular barrier.
  It is an assembly line such as this that the value of the careful inspection at earlier stages becomes so apparent, for movement after movement goes through all the assembly stages without a hitch, and progress is smooth and rapid. Even so, inspection and testing continues all the way. 
  An interesting detail is that a dummy winding stem is used all through assembly, the real one only being fitted at the casing stage. Very careful checks and tests are applied to the keyless work. This part of a watch often has to bear the brunt of unskilled winding or setting. 
  There are 7 pages on the visit in 1962. Use the box links below to see the other pages