Internet Horology Club 185
How did They Do That ??

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October 06, 2006, 18:21
John Pavlik
How did They Do That ??
I find this English watch plate quite a wathcmakers nightmare..How did they drill 38 holes, with 14 of them threaded, and have them aligned properly.. Mind you the diameter is 39mm..
Plate dates to approx. 1845 or so..


October 06, 2006, 21:31
Edward L. Parsons, Jr.
John,

I'm no watchmaker, but I am a mechanical engineer, and also a trained machinist, with an extensive background in precision machining of metal parts.

Today, making a hole pattern like that with precisely the right alignment and relative positioning would be no problem for a numerically controlled (NC) drilling machine.

Back in mid-19th Century, it would have been more difficult, but still possible, through the use of a different technology that we call "hard tooling" today.

The desired layout of holes would be transferred to a pattern, which would then be used to create a drill fixture or gig, which would be used to guide the drills used to make the holes in the individual watch plates.


Best Regards,

Ed
October 06, 2006, 22:51
Peter S. Balkan
From what I understand, the old vs. new machining is what makes the Hamilton 992B/950B models so unique.

I understand that the top plates (bridges) were assembled onto the pillar plate for drilling the holes for the pivot jewels in perfect alignment. This is one reason why the all the plates and bridges were stamped with the movement's serial numbers. A different bridge or top-plate MIGHT work ok but there was no guarantee unless they matched.

When the 992B/950B models were introduced, manufacturing had become so precise that the bridges could be made entirely independent of the pillar plates and, therefore, there was no reason to mark them with a serial number. Ed is precisely correct about these advances.

I find it a shame that fashion trends and quartz technology deprived the American public of knowing the joy of carrying a fine pocket watch. Who knows what further advances might have seen production had the era not ended.

Some say that the DeLong escapement might have been able to compete, head to head with quartz, at least for awhile. The Delong escapement offered extremely fine accuracy along with the possibility of long-term winding.....

But.... alas....