Internet Horology Club 185
Elgin Convertible Conversion Tutorial
August 03, 2004, 22:39John D. Duvall
Elgin Convertible Conversion Tutorial
Note: Compare the assembled movement with the exploded view.
The pillar plate has two areas for the winding arbor to fit; the Hunter position and the Open Face (OF) position. By swapping position of the Crown Wheel and Winding Arbor, the movement can be “converted” to either an Open Face or Hunter movement.
In the “wind” position (setting lever stowed), the Setting Spring pushes the Ratchet Wheel down and away from the Setting Wheel and causes the Ratchet Wheel to engage the Ratchet. Turning the Winding Arbor will now turn the Crown Wheel. The Crown Wheel interfaces with and turns the Ratchet Wheel. The Ratchet Wheel turns the mainspring arbor via its contact with the Ratchet (the ratcheted surface under the Ratchet Wheel interfaces with the Ratchet).
In the “set” position, the setting lever is pulled out which pushes a small pin through a hole in the pillar plate. This action lifts the Setting Spring, which raises the Ratchet Wheel (via fork and groove) away from the Ratchet and allows it to interface with the Setting Wheel. When the Winding Arbor is turned, the Ratchet Wheel will turn the Setting Wheel. The Setting Wheel has an arbor that extends through the hollowed Center Wheel arbor. The cannon pinion is attached to the end of this arbor. The setting wheel arbor has an interference fit with the Center Wheel arbor so the hands can be set. Under the dial, the cannon pinion, hour and minute wheels function the same as a conventional movement to drive the hour and minute hands.
Note: The Ratchet Wheel stays in contact with the Crown Wheel in both "wind" and "set" positions.
August 03, 2004, 23:19Tom Seymour
Very good John. I have wondered how it worked, but have never had one "in hand" to check it out. Thanks
August 03, 2004, 23:27Dr. Debbie Irvine
Great work as always John!
August 04, 2004, 11:24Ed Ueberall
John, excellent job, as usual. You have a real ability to show complicated mechanisms in a way that makes them easily understandable.
IHC Member 34
August 04, 2004, 14:24Jessica Lane
While I'm pondering this, I'd like to add my thanks. You have such depth of knowledge, your introductory tutorials are very helpful.
August 06, 2004, 07:06John D. Duvall
Thanks to everyone for their kind comments.
November 14, 2004, 01:20Lindell V. Riddle
After carefully studying this tutorial I finally got up enough nerve to change mine from hunter to open-faced setup. Thanks to your detailed explanation I now understand these very cool watches!
November 14, 2004, 15:22Frank Juchniewicz
Thanks for the latest tutorial. Another fine job. I have not run across one yet, but when I do, I'll know what I'm looking at.
November 15, 2004, 13:34John Pavlik
Don't forget if you do find a case, it needs that female stem...trying to change that has never been very easy for me..
Hats off your fine explainations..
November 16, 2004, 22:46John D. Duvall
When searching for a 16s case, look for one that has a setscrew in the pendant. These were for pendant wind (female stem square) and lever set. They are indeed hard to find.
November 17, 2004, 08:51John Pavlik
That is true only some of the time. I have many with the set screw and have the male stem. They are mostly 18sz but I have been fooled many times assuming that they had the female stem..You are correct, all with the set screw are leverset..except some harder to find Waltham 57's with stem winding and key set..had one of those once, sold it, not to smart on my part..
November 17, 2004, 23:14John D. Duvall
I totally agree with you. I should have provided more information. When searching for a 16s case that 'might' fit one of these Elgin convertible movements, one should research the movement that is in the case to see if it has a male winding arbor (AKA stem in movement). I recently purchased an old Elgin 16s watch knowing the movement had a male winding arbor and a case with female stem (setscrew in pendant). I haven't attempted a fit check of the convertible movement yet but will post the results in this thread.
Specifically, I would look for a case housing a 16s Elgin Model 3. Model's 1 & 2 are convertibles. The Model 4 (doctor's watch) requires even a deeper case because of the sweep seconds wheel and arbor cock. Many of the Model 4 cases were made by J. Boss and utilized a special spacer ring. These J. Boss cases might work with a 17s movement if the spacer ring is removed. I really don't know.
To the best of my knowledge, 16s American watch cases produced in significant quantities that had a female stem would be found on the above Elgin models and possibly the Waltham Model 1872.
As John pointed out, there are other American 16s, lever-set movements that employ a female winding arbor and a male stem held in the case by the pendant setscrew. However, I believe these would be even harder to find.
November 18, 2004, 21:56John D. Duvall
Of course there's always a workaround........