Water Resistance and non-screw-down crowns: Question

I see watches like the Seiko 5 Superior and Citizen Oxy Military which are marked as being water-resistant to 100m although the crowns are non-screw-down. Is this feasible? And if so, why are so many watches which have the same or lesser WR rating made with screw-down-crowns? The reason I'm asking is that these two watches seem like incredible value for money, and I'm wondering if I'm missing something. And yes, I gather that WR, as with many another x-resistant tag, is the subject of certain amount of a snake oil sales technique.

Still, I remain....

Confused.

Kamraj

I have a watch I put together, AS1802, which has a non-screwdown crown supposedly rated to 200m. I've only tested it to 140m (wet test), but that was successful.

Best wishes,
Bob

I have an old Breitling Wings without a non-screw-down crown. Tested ok at 100m. It also has a pop on case back rather than screw in.

They since changed that design but it worked fine.

Joe.

The Glycine Incursore doesn't have a screw down crown and is rated to 300 metres. It depends on the crown design, some have 2 or 3 "O" ring seals, others have no seals at all.

Eddie

My plastic Traser P6500 has two fat O-ring seals and has been tested to 100 meters (nominally 30, but technically identical with the 200-meter Luminox).

Several early dive watches did not have screw-down crowns (BP 50 fathoms, IIRC).

There were some Doxa models that didn't have screwdown crowns either. I think the one though that I hear was inferior and prone to leakage was the non screwdown on the Omega SM300's.

A lot of watches from e.g. Seiko has WR 100 but doesn't have a screw-down crown. I think it's fairly common and it would be surprising if there was a problem with that - that would make a lot of unhappy costumers for a lot of companies.

I have a Seiko 5 Superior with a WR of 100 meters. Although it hasn't seen a lot of wet action I think that the claimed WR would hold true if tested.

I also have a cheap Certina diver with WR 100 that I've used for swimming and sports (thougt not scuba) and although it has taken a lot of beating it has never leaked or failed in any other ways. The Certina doesn't feature a screw-down crown either.

You're absolutely right that the Seiko 5 Superiors are exceptional VFM. Sapphire crystal, solid steel bracelet, low-end but functional movement, WR 100 and smashing looks at that price is very impressive :D

Thanks people. I suppose it's just horses for courses which option the deisgner opts for when making the watch water resistant. Screw-down still "seems safer" to me, but I know I'm daft.

Kamraj

Maybe it's all been a big confidence trick to change customer perceptions? Glycine have shown that you don't need a screw down crown and in almost 50 years of wearing a watch, I'm certain that I don't need a sapphire crystal. I've never damaged a mineral crystal badly enough to warrant replacement.

Eddie

I always thought that the screw down crown, on diver's watches, was initially developed, less to stop water getting in, than to stop the accidental movement of the hands when underwater and thus messing up any dive calculations.

I had one of the Seiko 6139 chronos when I was in the army (shows how old I am :-) ) and the rating on that is only 70m, with no screw down crown and pushers too but that I wore everywhere, underwater, jungle, snow, you name it and it never let me down. It amuses me when I hear people with watches with a water resistance rating of 200m asking if it's safe to swim with it :-)

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Originally Posted by swanbourne

I'm certain that I don't need a sapphire crystal. I've never damaged a mineral crystal badly enough to warrant replacement.

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Ditto that. Which makes all that repetitive wailing and rending of togas we've had to endure over Seiko's eminently sensible decision to equip with Marine Master with a Hardlex mineral crystal so exasperating.

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Originally Posted by Seamaster73

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Originally Posted by swanbourne

I'm certain that I don't need a sapphire crystal. I've never damaged a mineral crystal badly enough to warrant replacement.

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Ditto that. Which makes all that repetitive wailing and rending of togas we've had to endure over Seiko's eminently sensible decision to equip with Marine Master with a Hardlex mineral crystal so exasperating.

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Are there different kinds of mineral crystals? I've scratched some very badly even though I've been fairly careful, and yet a cheap beater of mine also with mineral crystal that should have been scratched beyond recognition long ago is still perfect without a single scratch on it.

The position of the crystal relative to the bezel seems to be of equal importance to the hardness of the glass. Recessed crystal and you're safe, but if the crystal is higher than the top of the bezel you're likely to scratch it unless it's sapphire.

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Originally Posted by Mabuse

Are there different kinds of mineral crystals? I've scratched some very badly even though I've been fairly careful, and yet a cheap beater of mine also with mineral crystal that should have been scratched beyond recognition long ago is still perfect without a single scratch on it.

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IIRC, mineral crystal can be chemically (?) hardened. Presumably less or no hardening would cut costs, so, yes, I would assume there are different grades of mineral crystal around.

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Originally Posted by Crusader

IIRC, mineral crystal can be chemically (?) hardened. Presumably less or no hardening would cut costs, so, yes, I would assume there are different grades of mineral crystal around.

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That's interesting information, thanks :) Reading your reply and Eddie's mentioning of Glycine made me think of their mineral crystals, which I think they refer to as a certain grade of hardness called K1 or something like that.

I know water resistance has been debated to death, but I noticed that some retailers now state that you need a 1000m rating for a watch to be suitable for SCUBA diving. A 200m rating isn’t good enough for diving, e.g. Ernest Jones.

Is this marketing baloney or have water resistance ratings changed?

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Originally Posted by Kamraj

I see watches like the Seiko 5 Superior and Citizen Oxy Military which are marked as being water-resistant to 100m although the crowns are non-screw-down. Is this feasible?

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From my (shower, not diving) experience, absolutely.

The pressure of the water as you get lower will push the crown into the seal anyway.

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Originally Posted by Dougal

I know water resistance has been debated to death, but I noticed that some retailers now state that you need a 1000m rating for a watch to be suitable for SCUBA diving. A 200m rating isn’t good enough for diving, e.g. Ernest Jones.

Is this marketing baloney or have water resistance ratings changed?

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Its total marketing baloney. There are many extremely competent dive watches rated at 200m. Even 300m is becoming excessive IMO

The early Tag F1s were 200m rated and didn't have screw down crowns, I wore mine for years swimming, showering in a sauna.
I didn't know that seals should be checked either so they weren't between battery changes.

I saw Hugh Fernley whatshisname scuba dive in his on TV.




So it seems to me quite possible to use a 200m dive watch in water even without a screw down crown.

Its the seals on the stem that provide water resistance in many watch designs, such as the Marinemasters. The screw-down component makes sure the stem can't move, but isn't adding water resistance to those designs.

Jaeger Deep Sea has no screw down pushers but is a proper ISO 6425 certified diving watch - to 100m...https://uploads.tapatalk-cdn.com/201...253bc3305c.jpg

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Originally Posted by bedlam

Its the seals on the stem that provide water resistance in many watch designs, such as the Marinemasters. The screw-down component makes sure the stem can't move, but isn't adding water resistance to those designs.

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Exactly - having a screw down crown guards against accidental knocks underwater but does not contribute to Water Resistance per se. Unless the watch is designed for serious underwater work, a screw down crown is mostly for marketing purposes.

Something struck me the other day - on most chrono watches, you aren't supposed to press the chrono pushers underwater. Yet many have a Screw down crown! Isn't it wildly contradictory that the crown is protected against knocks, but the chrono pushers make the watch vulnerable if knocked? Seiko do loads of watches like this. Its just daft IMHO.

This is simply not true, there are lots of screwdown designs where the screwing down tightens on one of the O-rings. For instance, the best, Rolex Twinlock and Triplock crowns screw down onto an o-ring top surface, as well as having rings sealing onto the stem.

So the scrwing down definitely does contribute to the sealing

Look at the top labelled O-ring here, complressed on left, free on the right

http://4.bp.blogspot.com/-NcqKQ87niY...s1600/twtr.jpg

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Originally Posted by sweets

This is simply not true, there are lots of screwdown designs where the screwing down tightens on one of the O-rings. For instance, the best, Rolex Twinlock and Triplock crowns screw down onto an o-ring top surface, as well as having rings sealing onto the stem.

So the scrwing down definitely does contribute to the sealing

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We were initially discussing non-screw down crowns being able to have decent water resistance.

Additionally, some screwdown designs, like Rolex require the crown be screwed down properly for full water resistance, whereas (like I said) most Seikos don't. Neither is 'best', the Seiko achieves the same water resistance with a simpler design and the Rolex has more redundancy (if you remember to screw the crown down).

What exactly was said that isn't true?

This

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Originally Posted by MrGrumpy

Exactly - having a screw down crown guards against accidental knocks underwater but does not contribute to Water Resistance per se.

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is not true

Yet...a watch rated as WR100m without a screw down crown is (or should be!) WR to 100m, exactly the same as watch rated to 100m with a screw down crown. It either meets the standard or it doesn't, or the standard is therefore utterly meaningless! As many have pointed out, a screw down crown is not essential to have very high WR ratings, as they are many actual examples without in production.

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Originally Posted by sweets

This



is not true

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In the watches that were being discussed it absolutely is true.

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Originally Posted by sweets

This...is not true

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In the watches that were being discussed it absolutely is true.

We were talking about how non-screw down designs could be water resistant, and I also mentioned Seiko. Screwdown crowns to not add water resistance in those watches.

Try again.

I have had 2 Sinn UX. The first UX with an earlier serial number had a screw down crown. And it was reassuring for such a watch.
The second does not have a screw down crown.
From a psychological perspective, there is something comforting about the screw down crown!

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Originally Posted by Kiloman

From a psychological perspective, there is something comforting about the screw down crown!

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For some. :smug:

I've yet to have a watch with a screw down crown, so still haven't had the opportunity to strip the threads

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Originally Posted by bedlam

In the watches that were being discussed it absolutely is true.

We were talking about how non-screw down designs could be water resistant, and I also mentioned Seiko. Screwdown crowns to not add water resistance in those watches.

Try again.

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I just noticed this, how unnecessarily aggressive of you.
No need for me to try again, I made my point, which I stand by.

Dave

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Originally Posted by sweets

I just noticed this, how unnecessarily aggressive of you.
No need for me to try again, I made my point, which I stand by.

Dave

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Screw down crowns are unnecessary for Scuba diving.

When Nuno Gomes set the world record for the deepest Scuba dive he was wearing a G Shock Frogman and not even a then current one but an older vintage model. G Shocks Frogman have pushers only, which can be used underwater and which rely on gaskets only to maintain water resistance.

Screw down crowns may prevent unwanted time changes but it is the gaskets that provide the WR. However, screw down crowns are a point of failure on a watch, push crowns are less likely to fail.



Mitch

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Originally Posted by sweets

I just noticed this, how unnecessarily aggressive of you.
No need for me to try again, I made my point, which I stand by.

Dave

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You waded into the discussion telling people they were wrong when they were not.

We were talking about non-screw down crowns and Seiko's and you said we were wrong because of a Rolex example. As an analogy, we were making a point about petrol engines and you jumped in saying we are wrong because of how things work in a diesel.

If you don't like an adversarial interaction then you shouldn't start them unnecessarily.

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Originally Posted by Mitch

Screw down crowns are unnecessary for Scuba diving.

When Nuno Gomes set the world record for the deepest Scuba dive he was wearing a G Shock Frogman and not even a then current one but an older vintage model. G Shocks Frogman have pushers only, which can be used underwater and which rely on gaskets only to maintain water resistance.

Screw down crowns may prevent unwanted time changes but it is the gaskets that provide the WR. However, screw down crowns are a point of failure on a watch, push crowns are less likely to fail.

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Screw-down crowns are unnecessary, but sweets makes a correct point that some designs (he notes the Rolex crown as one) engage additional seals when screwed down. Regardless, I would hope that a Rolex dive watch stem remains water resistant even if not screwed down.

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Originally Posted by Kamraj

Thanks people. I suppose it's just horses for courses which option the deisgner opts for when making the watch water resistant. Screw-down still "seems safer" to me, but I know I'm daft.

Kamraj

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Because it seems safer, it's quite a nice piece of marketing. I actually think it is safer, as a screwed down crown doesn't have the threat of being wiggled from side to side (from a wet suit cuff or sand jamming if you come off your surf board in shallow water) and opening a leak path. On the negative side though, they seem to frequently end up stripping their threads as owners will invariably push too hard as they engage and screw down the crown.

Sorry to be difficult - but the only point I made was that this specific sentence

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Originally Posted by MrGrumpy

Exactly - having a screw down crown guards against accidental knocks underwater but does not contribute to Water Resistance per se.

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Is wrong. And it is.

Seiko may not use this design, but many others, including Rolex (I merely use that as the easiest example for findingd diagrams on the net, as it is a design that has been around a while), use a system where the act of screwing the crown down presses on a seal, contributing to the WR. At the other end of the cost/quality scale I understand Vostok relies on a pressed seal, meaning there is zero WR if you forget it.
I put the diagram there to prove it. For a Triplock crown, but twinlock also uses it and so do many others, whether the pressed seal is inside the crown, on the threaded tube or elsewhere. There are some designs like my Armida where unscrewing the crown reveals one of the sealing gaskets sitting on the case end of the screwed tube.
This makes the generic claim that screw-down crowns only guard against knocks rather than aiding WR, false. It is simply untrue for many watches.

This review of the situation on this forum is very helpful in reviewing most types

Your discussion was not just limited to Seikos, but the merits of the design in general.
I am sorry if I used the wrong example. At present I have no Seiko, but I know Citizen also uses a lot of screwdown crowns, as I have one. Citizen do state that the screwdown is there to avoid accidental operation of the crown (not to seal).
I perfectly understand that the need to ensure that the crown is screwed in is a potential point of failure, so the Seiko/ Citizen stem seal has merit.
And so I also understand that screwdowns, per se, do not improve the seal of watches, and I never claimed as much.

But to deny that in many cases the act of screwing the crown down has no effect on WR is wrong. In many cases it is an integral part of the WR design.
I grant you that is not the case for all Seiko and Citizen watches, but that was not the point I was arguing with.

D

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Originally Posted by LorneG

Because it seems safer, it's quite a nice piece of marketing. I actually think it is safer, as a screwed down crown doesn't have the threat of being wiggled from side to side (from a wet suit cuff or sand jamming if you come off your surf board in shallow water) and opening a leak path. On the negative side though, they seem to frequently end up stripping their threads as owners will invariably push too hard as they engage and screw down the crown.

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I had a Fortis Titanium LE where the whole production was recalled because the large diameter Ti crown was too big for the thread, and a high percentage of owners had stripped the crown thread within weeks of the LE being released. They replaced the crown and stem FOC with a push one, with no change to the 200m WR,

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Originally Posted by sweets

I had a Fortis Titanium LE where the whole production was recalled because the large diameter Ti crown was too big for the thread, and a high percentage of owners had stripped the crown thread within weeks of the LE being released. They replaced the crown and stem FOC with a push one, with no change to the 200m WR,

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Blimey, that's not the sort of mistake you'd expect from Fortis

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Originally Posted by sweets

At the other end of the cost/quality scale I understand Vostok relies on a pressed seal, meaning there is zero WR if you forget it.

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That’s right. I know because I’ve
changed the seals myself.

Screwing in the crown does also lock the wobbly stem in place, but the stem is only loosely coupled to the rest of the movement at that point, so that doesn’t have any bearing on water resistance although it does protect the movement in the event of a bang on the crown.


I’m skipping over ‘other end of the cost/quality scale’. The flanged caseback with locking ring surely trumps the Oyster case. [emoji1787]

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Originally Posted by alfat33

I’m skipping over ‘other end of the cost/quality scale’. The flanged caseback with locking ring surely trumps the Oyster case. [emoji1787]

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Agreed, it is a much more elegantly engineered solution that means there is no requirement for the gasket O-ring to slip relative to either surface (and therefore, move, get pinched etc)

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Originally Posted by sweets

Agreed, it is a much more elegantly engineered solution that means there is no requirement for the gasket O-ring to slip relative to either surface (and therefore, move, get pinched etc)

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Now if they could just work on the +/-20spd timekeeping and the slightly iffy time setting, they could really give those Submariners a run for their money.