You got your watch... now what?

[sergio27]

great a place for n00bs like me!

Of course it will take me time to get all the abbreviations.

What does HEV mean? From what I gather it is something on the face of a watch?

[realreplica]

What does HEV mean? From what I gather it is something on the face of a watch?

Helium Escape Valve aka Helium Release Valve

A helium release valve, or helium escape valve, as it is also called, is a feature found on some diving watches. It provides functionality for professional divers operating at great depths for prolonged periods of time or under saturation.

When commercial divers operate at great depths, they often spend prolonged hours in diving bells under pressure breathing a breathing gas mix like trimix or similar, that contain the gases helium or hydrogen. Since helium molecules are the second smallest and hydrogen molecules the smallest found in nature, these gas molecules are able to work their way inside the watch, around any o-rings or other seals the watch may feature. This is not a problem as long as the divers stay under pressure, but when the decompression stops during resurfacing aren't long enough, a pressure difference builds up between the trapped gas(es) inside the watch case and its environment. Depending on the construction of the watch case and crystal, this effect can cause damage to the watch, like making the crystal pop off.

Whilst many watch companies react to this effect by simply offering an even more robust case/crystal construction, Rolex and Doxa S.A. however thought of a different concept when they co-created the helium escape valve in the 1960s (first introduced in the Rolex Submariner/Sea-Dweller and the Doxa Conquistador): A small, spring loaded one-way valve integrated in the watch case that is activated when the differential between the inner and the outside pressure reaches a critical level. Result: The valve releases the helium, hydrogen and/or other gases used in the breathing gas mix trapped inside the watch case.

Automatic helium release valves usually don't need any manual operation. There are however helium release valves featuring an additional screw-down crown at the side of the watch. When the diver starts to ascend, the diver simply unscrews the valve's crown to the full open position, allowing any breathing gas that may have been trapped inside the watch to escape during decompression.

Helium release valves can primarily be found on mechanical diving watches featuring a water/pressure resistance greater than 300 m (1000 ft) and therefore positioned as more extreme dive watches. Models that feature a helium release valve include most of the Omega Seamaster series, Rolex Sea Dweller, some dive watches from the Citizen Watch Co., Ltd, Breitling, Girard-Perregaux, Panerai, all watches produced by Enzo Mechana, and selected Doxa and Oris models. Other watch manufacturers such as Seiko still offer high-level dive watches that are guaranteed safe against the effects of helium gas without needing an additional opening in the case in form of a release valve.

[GMT66]

My $.02...
I have local a watchmaker who is both Omega and Rolex certified. He is a graduate of 2 different watchmaking schools, attending the Rolex school in Switzerland in the seventies. He's serviced a number of my reps, and spent a lot of time with me on some very useful education, as I like to tinker. He looks forward to the gen ETA's, hates the 7750's. His opinion: the Asian 7750's are filthy, shipped dry and bound to fail, and parts he orders do not fit on a routine basis. Especially the jewels. They are almost never the correct size. He's asked me not to take him any more. "They're not worth screwing around with".The bottom line, the Swiss ETA's I'm pretty sure any watchmaker outside of an AD will work on. The majority of the watches shipped from Switzerland have ETA movements in them (although a lot are modified to varying extents).The Asian movements you may get some push back on. I often wonder when I read posts that say that this Asian 7750 has been completely serviced. That to me means a complete tear down, cleaning lube and reassembly plus timing and regulation. I doubt it. But, I digress. I think you'll find that ETA movements won't be a problem with most independent WM's.

[realreplica]

My $.02...
I have local a watchmaker who is both Omega and Rolex certified. He is a graduate of 2 different watchmaking schools, attending the Rolex school in Switzerland in the seventies. He's serviced a number of my reps, and spent a lot of time with me on some very useful education, as I like to tinker. He looks forward to the gen ETA's, hates the 7750's. His opinion: the Asian 7750's are filthy, shipped dry and bound to fail, and parts he orders do not fit on a routine basis. Especially the jewels. They are almost never the correct size. He's asked me not to take him any more. "They're not worth screwing around with".The bottom line, the Swiss ETA's I'm pretty sure any watchmaker outside of an AD will work on. The majority of the watches shipped from Switzerland have ETA movements in them (although a lot are modified to varying extents).The Asian movements you may get some push back on. I often wonder when I read posts that say that this Asian 7750 has been completely serviced. That to me means a complete tear down, cleaning lube and reassembly plus timing and regulation. I doubt it. But, I digress. I think you'll find that ETA movements won't be a problem with most independent WM's.

I haven't yet disassembled one of the chrono movements and probably won't either anytime soon but that is the opinion of most of the people that work on the A7750. They aren't built to the standard of the ETA but if properly looked after they should last.
I'm sure the likes of Rex, Francisco, SpeedyG, Domenico, etc will completely disassemble, clean, oil and reassemble the A7750 without many problems.

[GMT66]

Point well taken. There are guys on this and other forums who specialize in the A 7750's. Most independent watchmakers have an aversion to them. Certainly didn't mean to call into question the integrity of the guys you mentioned!