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What vintage crown is this?


Champagnesky

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It looks like the brass threads extend to the base on the inside. Is that so, or is there a smooth area below the threads, that would seal against an o-ring? That tells you if it's a 702 vs a 703. You'll need the corresponding tube.

 

Also looks like you'll have trouble getting it to screw onto a stem.

 

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Maybe a 703? I have installed several vintage 703 crowns on my MBWs, JKFs and Vietnam cases and have had to put 7030 tubes in for them. The 702 crowns require a 7020 where the threads are closer to the case and the tube has a taller [censored] above the threads. So threads up in the crown 703. Threads close to the edge of the crown 702. Both tubes are available from clark for a inexpensive price on the bay.

Sent from my SM-G920P using Tapatalk

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10 hours ago, Nanuq said:

It looks like the brass threads extend to the base on the inside. Is that so, or is there a smooth area below the threads, that would seal against an o-ring? That tells you if it's a 702 vs a 703. You'll need the corresponding tube.

 

Also looks like you'll have trouble getting it to screw onto a stem.

 

 

10 hours ago, hugop said:

Maybe a 703? I have installed several vintage 703 crowns on my MBWs, JKFs and Vietnam cases and have had to put 7030 tubes in for them. The 702 crowns require a 7020 where the threads are closer to the case and the tube has a taller [censored] above the threads. So threads up in the crown 703. Threads close to the edge of the crown 702. Both tubes are available from clark for a inexpensive price on the bay.

Sent from my SM-G920P using Tapatalk
 

 thx mates, i assume its a 703 crown. I think the it has a lot of dirt inside so i will give it a go in a ultrasonic cleaner. I have a teflon grease i can also use.

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Not sure what was censored above. I thought I had typed [censored] but maybe something autocorrected to something else. In any case my apologies if I posted something inappropriate.

 

Sent from my SM-G920P using Tapatalk

 

 

Weird, it did it again. Why is a word that starts with fl and ends with ange censored? Anyway, here is a pic of a 702 tube for the op. A pic is worth a 1000 censored words. Haha

 

5e3c2ad3d7429c938f3b1eaf909a8ea0.jpg

 

 

 

 

 

 

99% sure you have a 702 crown there.

I defer to the expert on gen rolex bits dbane would certainly know.
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Here are some photos that show the difference.  The big difference  between a 702 and 703 is the added o-ring around the outside base of the 703 tube.  So the inside of the 703 crown has to be smooth there to seal against the o-ring.  The 702 has no o-ring in that position so the inside of the 702 crown is threaded to the base. 

 

Here's a cutaway view of a 702, you can see the threads at the base of the tube, and matching threads inside the crown.

 

701_cross_section.jpg

 

 

Here's a 702 set, with the threads visible

 

702_setb.jpg

 

 

Here's a comparison photo side by side, 702 and 703

 

702_703.jpg

 

 

Here's the smooth inner walls of the 703 where it seals on the o-ring

 

703.jpg

 

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Here are some photos that show the difference.  The big difference  between a 702 and 703 is the added o-ring around the outside base of the 703 tube.  So the inside of the 703 crown has to be smooth there to seal against the o-ring.  The 702 has no o-ring in that position so the inside of the 702 crown is threaded to the base. 
 
Here's a cutaway view of a 702, you can see the threads at the base of the tube, and matching threads inside the crown.
 
701_cross_section.thumb.jpg.ab701853ef37ddacc3b87ba5bcf0c64e.jpg
 
 
Here's a 702 set, with the threads visible
 
702_setb.jpg.952761eee8a16a3729e54cd4fdbfd4f9.jpg
 
 
Here's a comparison photo side by side, 702 and 703
 
702_703.jpg.12a8783fe7b72905f021255de217f8cc.jpg
 
 
Here's the smooth inner walls of the 703 where it seals on the o-ring
 
703.jpg.dac41e832c2af2e4a758f200429a908d.jpg
 

Perfect Nanuq!


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Here are some photos that show the difference.  The big difference  between a 702 and 703 is the added o-ring around the outside base of the 703 tube.  So the inside of the 703 crown has to be smooth there to seal against the o-ring.  The 702 has no o-ring in that position so the inside of the 702 crown is threaded to the base. 
 
Here's a cutaway view of a 702, you can see the threads at the base of the tube, and matching threads inside the crown.
 
701_cross_section.thumb.jpg.ab701853ef37ddacc3b87ba5bcf0c64e.jpg
 
 
Here's a 702 set, with the threads visible
 
702_setb.jpg.952761eee8a16a3729e54cd4fdbfd4f9.jpg
 
 
Here's a comparison photo side by side, 702 and 703
 
702_703.jpg.12a8783fe7b72905f021255de217f8cc.jpg
 
 
Here's the smooth inner walls of the 703 where it seals on the o-ring
 
703.jpg.dac41e832c2af2e4a758f200429a908d.jpg
 

Thx Nanuq its a 703 i have then. IT fitted on a tc tube I had, but it has a lot of dirt inside so I will need to clean it. Will add some teflon grease inside too.


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Yes it looks like a 703. The one on the middle looks rep to me. The side profile and thickness on the right looks more gen or possibly TC.
 
Sent from my SM-G920P using Tapatalk
 
 
Here is a gen 704 to compare...
05cf8aa0f9a59f038cd19f800c6a8e72.jpgbc84f4c1b962b1f2c2ae1d8aa51343be.jpg
 
 

+1

left 703 and right 704 are Gen. middle one is a rep


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Ronin, see the gen 703 on the left?  Look closely and you can see thin stainless steel wrapped over a brass core.  It's visible on the edge that would be closest to the case, where the tiny folds overlap.

 

Only gen crowns are made like this, 700 - 702 - 703.  The 704 is "monobloc" so it's carved from one piece of steel, hence no need for steel wrap over a brass core.  It also has much thinner walls than a 703.

 

MBW "703" crowns have nice thick walls, just like the middle one in your photo.  Hint: They're great raw material for using a dremel and file to put a bevel on the case side and mimic a 702.

 

So IMO you have, left to right, gen 703, MBW 703 and gen 704.

 

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