Has anyone any ideas regarding extra screw on left hand side of barrel plate I have seen obout 10 of these bridges with extra screws on varying models railway king all jewel counts , rwk special, the president, time king all of the above have had both the 2 and 3 screws plate

Interesting Jeff, I have seen it before but didn't take much notice except that is only seen on Open Face models,(not all of them either) as I see yours is also.

Also not just the higher Grades and not just in the 300,000 serial range either. Have you had yours apart to see what if it goes into something besides just the top-plate?

Where that extra screw is position is pretty close to directly above the Winding arbor retaining bridge that is fitted to the dial plate. There is no pillar in that position except for the normal "barrel bridge retaining" screw pillar on the one screw below that extra screw.

With these Columbus movements the Company used the same Train Wheel layout (position) for the Open Face as what they had for the Hunter movements.

So the only difference was the moving of 1 dial plate pillar to accommodate the the different position of the winding mechanism and it's bridge work on the dial plate and the machining for that.

There is absolutely no need for the extra screw to be there under normally production circumstances as it goes nowhere and does nothing as far as I can see.

The only theory that I have is to do with the use of the Factory at one time using some plates from hunter movements and some plates from open face movements on the same watch (the re-purposing of unused materials).

Therefore, the extra hole could have been used for positioning of the plates again for some sort of machining purpose during this production process.

I have no proof of this, but it would not surprise me at all, as I have seen stranger things done by Factories to fill orders. Maybe someone else out there in the Collector world has more info as to why

Thanks Bila for reply the first one I saw I thought was done by a watchmaker making repairs. The screw closest to the "c" in columbus does not hold the plate as the hole is drilled straight through the plate this screw is the common one to the 2 and 3 screw barrel plate the other holds the barrel plate the main plate so with the other main plate screw being so close as you say it seems to serve no reall purpose to the functional integratey of the movement