How does a non-screw down crown Omega achieve 150m WR?

Chai86 · Feb 10, 2022

I have a Seamaster Planet Ocean that has a screw down crown (+Helium valve) and it has 600m WR.

My 34mm AT is purported to have 150m WR and it doesn't have a screw down crown! That seems bonkers to me. Does anyone know how by simply just pushing the crown back, closest to the watch case, Omega can achieve this?

SkunkPrince · Feb 10, 2022

The greater the depth, the greater the pressure on the crown, and the tighter it seals. Nothing magical, just some damn fine engineering and manufacturing.

padders · Feb 10, 2022

SkunkPrince
The greater the depth, the greater the pressure on the crown, and the tighter it seals. Nothing magical, just some damn fine engineering and manufacturing.

That would be the now discredited Naiad crown design. Modern crowns work whether pulled in or out (up to a point). The screw in thread is a red herring. That just prevents you pulling the bugger out at depth but it will seal (when healthy) in or out so screw down ain’t an issue. Unless you are diving on Heliox that that is.

Archer · Feb 10, 2022

Simple...there’s a seal inside the crown. A crown doesn’t have to screw down to be water resistant, as the threads themselves do very little to prevent water from getting in.

Caliber561 · Feb 10, 2022

Archer
Simple...there’s a seal inside the crown. A crown doesn’t have to screw down to be water resistant, as the threads themselves do very little to prevent water from getting in.

Unfortunately, this seems to be a misconception that has propagated about as much as the 'dynamic pressure' one.

Chai86 · Feb 11, 2022

I'm just surprised that i can just pop the crown in, and there you go, up to 150m water resistance! Makes me a little suspicious thats all

Archer · Feb 11, 2022

C Chai86
I'm just surprised that i can just pop the crown in, and there you go, up to 150m water resistance! Makes me a little suspicious thats all

No reason to be suspicious really. Omega is a brand that isn't going to lie to you about water resistance.

Dan S · Feb 11, 2022

There are tons of watches with 15-20 bar depth ratings that don't have screw down crowns. I hear this mythology about screw-down crowns all the time, and it's clear that people have not looked at schematic diagrams to understand how the seals work. The screwdown crown is useful to keep the crown from being jostled while underwater.

ConElPueblo · Feb 11, 2022

Certina DS watches from 1959 were rated to 200M without screw-in crowns.

How does a non-screw down crown Omega achieve 150m WR?

Chai86

SkunkPrince

padders

Archer

Caliber561

Chai86

Archer

Dan S

ConElPueblo

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