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So I purchased a Pulsar Diver salesman sample, watch had no stem and movement was glued. It contained a Pulsar V736 movement upon some research it seemed the Seiko 7n36 is the same movement, dial fit the movement fine and the movements look identical. Issue is with the stem and crown. The stem is tap 11 and I believe the crown is tap 13. Is there anyway to reduce the stem down to a tap 13? I know about stem converters but have not seen any that have a crown side of 13 and watch side of 11. Didn’t pay a lot for the watch or movement but hate to see a watch die so to speak.

Regards

Ren


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2500M_Sub...Hello!

Although I don't know this watch, I think that I do know when it's time to search-out an Independent watchmaker with LOTS of spare / older / weird (!) parts kicking around the shop. I've done a fair amount of mixing & matching of cases and crowns and stems and lots of other stuff, and it's been possible only because i had box after box of things from which to choose...

..worked for me, and I'm sure I'm not alone.

Michael.
 

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Whats the case #? Maybe finding what a proper crown should be would make it work


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Discussion Starter #4
2500M_Sub...Hello!

Although I don't know this watch, I think that I do know when it's time to search-out an Independent watchmaker with LOTS of spare / older / weird (!) parts kicking around the shop. I've done a fair amount of mixing & matching of cases and crowns and stems and lots of other stuff, and it's been possible only because i had box after box of things from which to choose...

..worked for me, and I'm sure I'm not alone.

Michael.
Yeah, wish I knew someone like that, I have a pretty decent watchmaker locally but he couldn't do anything with it or it wasn't worth his while so picking the watch back up on Saturday.

Regards,

Ren
 

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Discussion Starter #5
Whats the case #? Maybe finding what a proper crown should be would make it work


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The case came with the correct crown, problem is I cant locate the original movement and stem. The 7N36 fits the watch perfectly, even looks exactly the same and according to Borel's database the original movement used a tap 11 stem but the stem is too fat to screw into the crown. My watchmaker mumbled something about tap 13 so guessing that is the size I need. Checked Borel's site and they do not have the crown available. The watch model is V736-6A60.

Regards,

Ren

Pic of the watch with new movement installed.

[
 

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The case came with the correct crown, problem is I cant locate the original movement and stem. The 7N36 fits the watch perfectly, even looks exactly the same and according to Borel's database the original movement used a tap 11 stem but the stem is too fat to screw into the crown. My watchmaker mumbled something about tap 13 so guessing that is the size I need. Checked Borel's site and they do not have the crown available. The watch model is V736-6A60.

Regards,

Ren

Pic of the watch with new movement installed.

[


FYI v736 and 7N36 uses the exact same stem.


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You should be able to drill it oversize and retap it. Various suppliers have taps. ofrei has a 090mm tap for $7.50.
 

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Discussion Starter #8
FYI v736 and 7N36 uses the exact same stem.


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Yeah that’s what I saw in my research but tell that to the crown where tap 11 is too fat to fit into the hole and for sure the crown is correct to the watch as I have seen pics of the same model and also have another model I purchased with a v736 movement that works and the crown is the same but not going to take it apart before I have two watches that don’t work.

Regards

Ren


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Discussion Starter #9
You should be able to drill it oversize and retap it. Various suppliers have taps. ofrei has a 090mm tap for $7.50.
Thanks I will check it out, was hesitating to do anything to the crown because I can’t find a replacement so was thinking I could modify the stem since I can easily get another if I screw it up but that may be the only option.

Regards

Ren


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If the crown were plated brass and I had a drill press, I would consider it. If I didn't have a press or it was made of stainless, you are asking to break the tap off in the crown and now it's worse than useless. I'd pay attention to @Acidstain, he knows his stuff.
 

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Yeah that’s what I saw in my research but tell that to the crown where tap 11 is too fat to fit into the hole and for sure the crown is correct to the watch as I have seen pics of the same model and also have another model I purchased with a v736 movement that works and the crown is the same but not going to take it apart before I have two watches that don’t work.

Regards

Ren


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I'll check and see if i have a crown tomorrow, and confirm if it's tap11 or 13. tap 13 is usually seen on the thinnest of the thin seiko lasalles. Maybe since it's a salesman's sample, they intentionally inclulded a non functional crown. i have seen samples where they have bezel's and crowns glued on to the case, and hands attached to fake hour wheels taped to the back of the dial.
 

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Discussion Starter #13
I'll check and see if i have a crown tomorrow, and confirm if it's tap11 or 13. tap 13 is usually seen on the thinnest of the thin seiko lasalles. Maybe since it's a salesman's sample, they intentionally inclulded a non functional crown. i have seen samples where they have bezel's and crowns glued on to the case, and hands attached to fake hour wheels taped to the back of the dial.
Thank you, Yeah tap 13 seems to be really thin, on the other model I have the stem is solid and you cannot see any threads so maybe it was a special stem that has a thin portion that screws into the crown? On this sample it actually came with a movement except the stem and the movement was glued, crown was just screwed down no glue.

Regards,

Ren
 

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Discussion Starter #14
If the crown were plated brass and I had a drill press, I would consider it. If I didn't have a press or it was made of stainless, you are asking to break the tap off in the crown and now it's worse than useless. I'd pay attention to @Acidstain, he knows his stuff.
You have a great point, think I will leave the crown alone then, because it is steel and I do not have a drill press, the crown also has a spring mechanism in it so the stem could travel a bit back an forth once it is screwed in.

Regards,

Ren
 

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Discussion Starter #16
It’s not tap 13. Its a 1 piece combo stem crown, ala skx stems. They were not meant to be separated.




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Thanks for the insight, now it makes sense why the stem wont fit the crown.

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Ren
 

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You have a great point, think I will leave the crown alone then, because it is steel and I do not have a drill press, the crown also has a spring mechanism in it so the stem could travel a bit back an forth once it is screwed in.
Yeah, that really complicates the problem. The only solution I see would be to freeze the mechanism with something like machinist's wax and then you run the risk of never getting it completely out again.

The reason I mentioned a drill press is that once drilled, you use the drill press as a guide for the tap. Taps either have a center hole or a conical surface at the non-business end and the tap handle has a center hole as well. So once you have your hole drilled, you put either a center or a reverse center in the chuck and use it to guide the tap and keep it straight. Picture the tap in the tap holder. You start it in the hole you just drilled but then push the center into the hole in the tap handle to keep it centered. This keeps you from pushing the tap sideways after it bites which is the main reason taps get broken in the hole. They also make tap frames which are just like a staking frame, but there's nothing to fixture the part. These just keep the tap perpendicular.

A center is a piece of round stock, typically High Speed Steel, that has a 60 degree point ground on an end, similar to a lathe dead center. A reverse center is the opposite, a 60 degree cone cut into a piece of HSS. The center is easy to make, the reverse center not so much.

I go to all the trouble to spell this out because this knowledge turned my from a crappy tapper to a proficient tapper back when I was working my way through college as a machinist (some forty years ago).
 

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Discussion Starter #18
Yeah, that really complicates the problem. The only solution I see would be to freeze the mechanism with something like machinist's wax and then you run the risk of never getting it completely out again.

The reason I mentioned a drill press is that once drilled, you use the drill press as a guide for the tap. Taps either have a center hole or a conical surface at the non-business end and the tap handle has a center hole as well. So once you have your hole drilled, you put either a center or a reverse center in the chuck and use it to guide the tap and keep it straight. Picture the tap in the tap holder. You start it in the hole you just drilled but then push the center into the hole in the tap handle to keep it centered. This keeps you from pushing the tap sideways after it bites which is the main reason taps get broken in the hole. They also make tap frames which are just like a staking frame, but there's nothing to fixture the part. These just keep the tap perpendicular.

A center is a piece of round stock, typically High Speed Steel, that has a 60 degree point ground on an end, similar to a lathe dead center. A reverse center is the opposite, a 60 degree cone cut into a piece of HSS. The center is easy to make, the reverse center not so much.

I go to all the trouble to spell this out because this knowledge turned my from a crappy tapper to a proficient tapper back when I was working my way through college as a machinist (some forty years ago).
Appreciate all the info, lucky for me Acidstain came through for me with the crown/stem combo I needed.

Regards

Ren


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