Hi,new guy looking for help.i recently came across this watch in my loft in a box of bits and am looking for any info on it. The watch is not working,broken mainspring I am told and needs a service. There are no military marks or numbers anywhere on the case or holder and the movement only has Swiss made and the no 12736 stamped on it. The watch face also has Swiss made in very faint lettering at the bottom and the no 497s on it. Any info would be much appreciated.
Thank you,Mike.

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Hi Michael.

Have you had a chance to read through the long thread in this forum about WW 1 cockpit watches? It discusses Mark IVa and Mark V cockpit watches to great length. Yours is nice since it has the mounting bracket with it and also because the winding stem has not been drilled at some point to add a ring there. Many are drilled like that unfortunately as people liked to use these as pocket watches after they were sold off as surplus. On the other hand, yours has a problem in that you say there are no markings on the back of the case. It should have deeply engraved there either a WD and broad arrow or an A and a broad arrow separated by a line. It is possible that someone has unfortunately been grinding and polishing the back of the case to remove those important markings, or it is perhaps more likely that someone has put the movement and dial into a different case that does not belong to that movement and dial. That is not entirely an uncommon situation in that these things were constantly being repaired during the war and also during the 100 years since the war ended. Watchmakers during all of that time did not know that future collectors would like to have these watches in entirely original condition. To them these were just watches that needed repairing with whatever was handy. If you decide to get your Mark IVa repaired you might keep in mind that unless you are a watchmaker yourself and know exactly what is wrong with it then you should not be surprised if it needs more repairs than just a spring. At the very least it needs to be completely disassembled down to each little part, cleaned, worn or broken parts replaced (often they are not available so don't be surprised if some of them have to be made by the watchmaker, then reassembled, oiled, and timed. It can cost a bit to get all of that done, but in the end you would have a nice watch, especially if you can find a donor watch case with the correct markings.

Thank you for the prompt reply and information,I was concerned about the lack of markings and whether the holder was an original item. I have read the threads on this and other forums to try and find out more so thanks again,I now have to decide whether to have it repaired or not.