Hi I need to open up this Elgin case but the back cover is unlike any I've seen. Not sure if you can tell from the photos but the case back is nearly flush, almost counter sunk and the circumference has a radius . I can't get a standard bench knife or other blade shape to bite. Any suggestions would be welcome.
The S&W 5946 9mm is worth the old college try... Joke aside...what about using a razor blade to carefully manipulate the caseback?
Heres a couple of frontal views ,and closest to an edge on view. No way its a front loader unless the movement were inserted before the crystal was pressed in place and I doubt that. I found a page on the Esslinger site with vacuum operated tools being used on a similar case back. They say the back must be loosened first but don't say how. Those tools aren't very expensive at all so I'm going to order one. I would like to hear from anyone who has used one of these and has some pointers. I already have a case closing press and I've used it a few times, also good for pressing a crystal in place. The vacuum tool can also be used for removing a crystal for replacement. BTW When gently shaking the watch the sound, or really just vibration through my fingers is what I'd expect from a bumper movement, if so the watch is likely older than I thought. At first it would stop very 15 seconds or so then began running for 3 to 6 hours as if nothing was wrong and was keeping accurate time in a short test. The motion of the second hand seems unusually smooth, I'm guessing this is a top drawer movement. I got it cheap enough that I think I can afford to invest a bit in getting it back in good working order. Its certainly a beauty. PS Its difficult to see but the hands and dial are very finely lumed and surprisingly the lume is still active. Behind each hour marker there's a tiny near invisible dot and the minute and hour hands have raised ridges with super thin ferrules filled with lume. Its possible the watch was re-lumed in the fairly recent past, if so it was done with great skill. I tested it by shining a LED flashlight on it for a few seconds and checking it in the dark, The hands and markers were very easily read. I'll test it with sunlight later. Whatever else this watch is a class act.
When following this approach it’s also prudent to first give fair warning by declaring loudly “OPEN UP OR I WILL SHOOT” as it may yield the desired result..
There was a similar Omega recently where the caseback was a press in and luckily the movement was able to be removed via the front, however, as your's doesn't have a front bezel/crystal assembly it must be a snap back. Use a good loupe and look for a recess/slit on the side of the case or caseback, possibly opposite the crown.
It would stand to reason that if the diameter of the back is smaller than the diameter of the crystal, it must be a front loader.
It looks to all the world like a snap back but I wonder if it has the split (sprung) flanges like on a JLC ... I'd get a Stanley knife blade and a loupe and try that. Hold the watch in your hands with a soft leather cloth (chamois). It gives plenty of grip while protecting both your fingers and the case from any slippage. Not trying to talk down to you (I'm sure you've opened plenty of watches) but go around the edge, don't lever up and down. Failing that ... might have to go to a pro.
I've opened just enough cases to know when I need and can appreciate any advice. It could be like the LC case back. I'll certainly keep that in mind.
I would recommend sending the watch to a competent watchmaker who would be able to answer the question upon inspection. I would assume it is a front loading watch. Why it has been suggested that it cannot be is beyond me. You will need a small pump such as the one pictured here. The watch will most likely have a split stem, which you will be able to find out by pulling the stem out harder than if you were to set the time. Insert the pump into the pendant tube, press down and the crystal will ‘pop’ off.
If the crystal fitted is a tension ring crystal (I can’t quite see) this is absolutely the wrong tool.
If it is a tension ring, it usually isn't a front loader. I echo @JimInOz's thought that it is a snapback: Try placing a thin blade (scalpel/hobby knife) there.
I would suggest that people stop telling the OP to blindly stick scalpel blades into the side of his watch case without any real evidence to do so. I am not saying the watch definitely is a monocoque case, however, to say that monocoque cases don’t have tensions rings is absurd. We are on the Omega forums, last time I checked, and the Omega Cosmic and Omega Dyanmic instantly come to mind as watches with tensioned crystals and monocoque cases.
If it was a monocoque case it seems to me it would be made of one piece. This one to my eyes clearly has a separate back. Base metal bezel, stainless steel back is clearly printed on the caseback. That to me means two separate pieces.
I am not denying that it may be a separate case back. However, to state watches with monocoque cases don’t have tension ring crystals is incorrect. Also, watches do not generally use plated materials on a case back as they would wear too quickly. So to state that this difinitevly proves it’s two pieces would too be hasty. We can again use a gold plated omega dynamic as our example. They have a stainless steel back but are a monocoque case.