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Discussion Starter #1
I have bought a sample chronograph, the movement and stem have been glued up so I am going to try and replace the movement with a Hattori YM62.

I can not find the spec for the Seiko crown (I think the original Seiko stem is part number 0351 583).
As the inside seems to be filled with some kind of resin/glue I was going to buy a replacement crown.

Can anyone help please?

Bern
 

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Try soaking the crown in some acetone or similar - it may soften the glue up enough. Worth a try before buying a crown.
In the absence of a pic - we need the 7t62-"xxxx" , there are literally hundreds of 7t62 variants.
 

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Discussion Starter #3
7s26b,
Acetone sounds worth a try. Is there nothing this stuff won't shift!

My 7T62 variant is a 0AS0.

If I have understood what info I can find on the two movements correctly the stem on the Hattori is a tap 10 and the one in the Seiko crown is a 9.
I assume this will mean either modifying a 10 to 9 stem extender or a hypodermic needle (to act as a sleeve) between the two stems?

Incidentally I came across these 7T62s after an ex work colleague showed me his old RAF version. Apparently there were a few made for the MOD by Seiko UK with Yellow dials which were specifically for Vulcan bomber crews. If this is true I bet they look rather smart.

One thing I have learnt from this is that I can now replace even the smallest hands without damaging either them or the dial as long as I remember to breath. :)

Thank you for your reply,
Bern
 

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AFAIK, the YM62 and 7T62 are one in the same, stems are both 0.9mm and the drawings look like they're virtually identical. If not, there are 3 or 4 other stems that will fit - so no need for extenders etc.
Crown part number, if you need it, is 8K55C6SNN1
Super glue debonder is also good.
 

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Discussion Starter #5
7s26b,
Having looked at both movements to my untrained eye they look exactly the same apart from the stampings.
I found the YM62 info on the Esslinger site and assumed the 7T62 would be 0.9mm.
Many thanks for the crown part number, I'll log it in my parts list for the project.
Super glue debonder = good call.
Your help is, as always, very much appreciated.
Bern
 

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I have bought a couple of sample cases. If you are luck enough to find the same case for a watch you own it is an awesome way to restore the watch case and bracelet to like new condition.

Acetone does indeed soften what appears to be some sort of white plastic they use to glue the crown to the case. Still after many soakings of acetone I have still never been able to get the crown to come out without a huge fight. I finally gave up and used a thin punch and drove it out carefully. For me it did not matter as I has the same exact crown and stem from the old watch. If you do not have an old doner watch driving the crown out will destroy it. I would not dare pry on it from the outside in fear of causing damage to the perfect condition case. The only real pain I can say about using sample cases to build a watch is the crown and the stem usually end up being the two most annoying parts to get correct. If at all possible try to save the crown. Jules & Borel sells replacement ones but they are listed by dimensions not application making it a pain to pick out the correct one and if you buy a new stem do not be surprised if you have to cut the threaded end down to shorted it to get the crown to fit flush. I enjoyed both projects I build using sample cases once I figured out those two things. It is a fun way to build your own watch.

Michael
 

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Discussion Starter #7
Michael,

Thank you for sharing all this, it is very much appreciated.

Have you tried using the tip of a hot soldering iron to melt or loosen the glue enough to pull the crown free? I saw this tip somewhere and found it has worked for me.

I agree trying to match a crown up is fun!
I have got a Seiko Crown but of course the movement is now a Hattori YM62 so now I need to try and find the right crown for that and get one that matches the Seiko style.

We are moving house next week so, just when I was getting into it, this will have to be put on hold for a while,
Bern
 

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Sorry I never checked back in this thread. I started another sample watch project last week. This time I decided since a little acetone helped a lot should work very good so I took the new case and stripped it down completely with only the two stems glue in. I filled a small jar up with about an inch of acetone and carefully placed the case crown side down in the acetone and let it sit 24 hours. After taking the case out of the acetone all it took was a little bit of pushing on the crown edge very slowly and it slid out in perfect shape! I had to clean out the tubes and I use a tooth pick to scrap out any of the plastic left in the threads of the crown. After that the crown threaded on the stem perfectly!

Michael
 
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