March 04, 2012, 18:28
Jon HartRockford 18s
166205 #
Anyone have knowledge on this style plate that goes over the mainspring barrel? I have never noticed the silver cap with the three (3) tiny screws.
March 04, 2012, 18:35
Theodore J. Brown Sr.Jon, I don't know Rockfords well enough to know what model that is, but it's an early one.I've seen one like that with a cut-out to make the escape wheel visible.Nice movement!Best regards, Ted.
March 04, 2012, 18:43
Jon HartHello Ted,
I dont have my rockford book with me. Therefore, like a fish without water. Trying to learn these Rockfords...

March 05, 2012, 12:55
Jon HartRockford Watch Company
Rockford Serial Numbers and Dates
Year S/N
1876 1,200
1877 22,600
1878 43,000
1879 64,000
1880 97,000
1881 138,000
1882 169,000
1883 200,000
1884 226,000
1885 247,000
1886 267,000
1887 287,000
1888 308,000
1889 328,000
Year S/N
1890 349,000
1891 369,000
1892 390,000
1893 410,000
1894 430,000
1895 450,000
1896 470,000
1897 490,000
1898 510,000
1899 530,000
1900 550,000
1901 570,000
1902 590,000
1903 610,000
Year S/N
1904 630,000
1905 650,000
1906 670,000
1907 690,000
1908 734,000
1909 790,000
1910 824,000
1911 880,000
1912 936,000
1913 958,000
1914 980,000
1915 1,000,000
March 05, 2012, 13:10
David AbbeJon, That plate is a Key Wind replacement for the Key Wind reinforcement collar plate. I expect it was made to facilitate using up the last surplus of orphaned Motor Barrel covers machined for Key Wind on late "transitional" movements.
March 05, 2012, 13:51
Jon HartDavid,
Thanks... The contrast between the two metals draws your eyes to the barrel cover.
Another thought that bounces around inside my head, from time to time...
On the two (2) RF 18s movement we have posted, why did they use the different setup for attaching the hairspring? I have seen this setup on a few IL 18s, too.
On the hairspring attached to the movement plate, not the balance cock, it would seem the hairspring would be sitting low or increasing the chances of it "rubbing" on the balance wheel.
V/r
Jon
March 05, 2012, 19:40
David AbbeAll later Hairspring studs are usually affixed to the Balance cock. Hairspring bridges on the movement plate were the early (and complicated) way to mount Hairsprings. This started because the earliest Hairsprings on Smerican Watches tended to be UNDER the balance wheel rather than above it. That required som nifty way to reach out inder the balance wheel and hold on to the outer end of the darn thing. Even this beautiful swiss fake Waltham 1857 style copied that early method.
March 06, 2012, 08:23
Jon HartThey sure do look tricky...
How does that swiss fake 1857 run? Never had good luck getting a 1857 to run very well.
April 03, 2012, 21:22
Jon HartThe oddest movement I have encounterd -
April 03, 2012, 21:23
Jon HartThe cannon pinion is for a key wind, but it has a lever set

April 03, 2012, 21:24
Jon HartJust cleaned and put back together - sooooo happy it is running like a champ!
Love these old Rockfords

Next, to find some new case screws!
April 04, 2012, 16:10
Richard M. JonesJohn I had the same manhole cover on a similar Rockford and I agree with Dave. An interesting thing about Rockford is that there seem to be a fair number of Rockford transitional movements around. More than some of the other makers. Maybe they did not quite trust the stem wound system, but I assume they decided the covers were the most economical way to go to use up materials on hand when they went to stem ind only. They are attractive though.