A customer recently sent his US watch company of Waltham to me for service. This was a small company that apparently didn't have a 16S lever set design for RR service, but came up with this solution.



This screw when loosened allows the crown to be pulled out for setting like any stem set watch. When turned down, however, it contacts one of the four flats on the stem and tightens against it, preventing an accidental pull of the crown.

The next picture shows the same screw with the movement apart. Note the shoulder on the screw traps it between the plates.



This next picture shows the stem next to the movement. The arrows show the tip of the stem which is broken off from the square end of the stem. It still works with the tip broken.



The next picture shows the red arrow pointing to the screw on the side that when loosened allows removal of the stem assembly.



Here is a picture of the watch back together.

This is the first watch I have seen with this type of setting mechanism and I found it very clever and interesting. Thought I'd share it with all of you and see if anyone can add any additional information.

Roger-

I have seen a lot of these first model US Watch Companies before but don't own one. It is a neat way for doing it. It would also keep the owner from playing around with it too easily and changing the time too.

Also a note for your customer. I have not seen the first model US watch co with the nickel plates before. All the ones I have seen have been the gilded versions. I haven't gone searching for them, but quite scarce versus the gilded plate first models in the searching/looking I have done.

Jared

Roger I have one question if the side screw holds the unit in place but allowed for the the crown to move up (set hands) or down (wind). If the top lock down screw that held the flat of the stem was locked how was the person able to wind the watch? I must be missing something since I figure the square of the stem turned the beveled gear seen in the picture that drove the mainspring wind mechanism then if the flat is locked that would also prevent winding.

Claude, sorry for not being more clear. The watch would not be able to wound with the plate screw turned down. It would have to be loosened to both set and wind the watch. The side screw allowed pulling the stem out to the setting position, but prevented the stem from coming out of the case. Note the large groove in the stem and the small groove. There is a spring loaded round arm that detents into the small groove in the setting position. The side screw tip sits in the larger groove preventing the stem from being pulled out past the small groove. I think it was a clever way for the company to meet a RR standard, but certainly not very convenient for the RR man who would have had to carry a small screwdriver with him to both set and wind his watch. Now for the non-RR person, just leaving the plate screw loose allows the crown to work just like any stem set/wound watch.

Some of the original stem wind/set Hamilton 950's had this screw too.

Regards! Mark

Thanks now it makes sense, I was wondering how you could lock it down and still wind it. It is nice that you posted it since a lot of times people's collecting habits are so tight that they never get to see the other brands and their designs.