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NCRich

Seiko NH35 swap in a JK Factory Sub - Tutorial

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NCRich

So I've always been dissatisfied with the DG2813 and even less satisfied with a more expensive asian clone of a 2836 in a vintage Rolex sub.  They are both assembled by small Chinese children in a dirty factory and they have no lubrication in the movement.  To add insult to injury the 2836 clone is the wrong beat rate, and is more expensive.  Still crap.  If you get a low beat Swiss pulled out of some old watch then it needs service to be decent.  Swiss 2836 still have the wrong beat rate. 

So enter the Seiko NH35.  Its a tank of a movement, still built by asians but in a clean factory with oil and QC.  Its got the right movement and is one of the most popular automatic movements in the world.  Purported to run for years through abuse and neglect.  Its got pretty much the right beat rate.  Only real beef anyone has with it is that its not quite as accurate as the vastly more expensive Swiss ETA 2836.  But it can be had for $35-40. 

I searched the boards and found people talking about how it was a waste of time trying to swap these in.  Wrong hand size, need gasket fabricated, datewheel, etc.  I looked at the specs and found not much difference at all.  Hand sizes:

NH35 150/90/21

DG2813 150/100/17

ETA 150/90/25

The case sizes, stem height, and movement height are very close as well.  When you figure in the plastic gasket the NH35 comes with its damn near a perfect fit.  So lets see how to do it.  I'm going to use my trusty old test DRSD.  Its had damn near everything smacked about on it.  Even got a countersunk Athaya crown.

 

So here is the NH35 with the plastic gasket it comes with.

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Here is the donor 2813 that came with the watch.  I use a single edge razor blade to carefully pry off the date wheel overlay.
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Here are both movements, I've moved the overlay onto the NH35.


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I glued the DWO onto the NH35 date wheel with a 5 minute epoxy.  I like to line up the 3 with the stem.
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Lay the dial on to see how it fits.  Got some time to move it.
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Hands are going to be the wrong size.  I'm just going to go to my BIG BOX O HANDS and pick the closest.


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I ended up using the 22 for the sec hand, and had to broach minute hand to fit.  Just a bit.  Both the handsets and the movements probably have .5mm error margins so it was no big deal.


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I put the dial on using double stick tape.


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The tape actually serves a double purpose, it holds on the dial but also adheres to the back of the rehaut to keep the movement in place.


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Hands on!


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Movement seated, looks good but just a little loose in the case.


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I'd measured all this stuff long before I started and ordered an appropriate gasket to snug it up.  I put it in before the stem was inserted.


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All in!  Fits like a glove.


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And, the finished product!


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Thanks for watching!

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WatchDog21

Very cool work here!  I wish I had the skill set to do this kind of stuff.  Carpal tunnel in both hands pretty much makes that a no go let alone getting all the parts back in without damaging or loosing them.

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WatchDog21

Did some noob  @NCRichpost this topic twice? :hyenas:

 :poke:

 

 

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BC1221

Damn. This is good to know.
Thanks NCRich!


Sent from my iPhone using Tapatalk

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NCRich
1 hour ago, WatchDog21 said:

Did some noob  @NCRichpost this topic twice? :hyenas:

 :poke:

 

 

No, I wanted it in both places.

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deju

That’s really impressive, way above my skill/patience level :lol:

 

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WatchDog21
32 minutes ago, NCRich said:

No, I wanted it in both places.

I thought I was going  wacko :wacko:.  I went "back" to the second posting  and started thinking  I was going crazy;  I know I posted a comment but poof it looked like it was gone! :thumbsup:

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KarmaToBurn

You're a bloody watch wizard!!! Well done.

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submarinerblue

I have a new San Martin Marine Master 300 (Seiko homage) with a NH35 and it’s accurate to within 5 seconds a day or better.

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fatarms

Nice work, @NCRich.  Is that the 1665 dial I scorched in the oven? :lol:

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NCRich
1 minute ago, fatarms said:

Nice work, @NCRich.  Is that the 1665 dial I scorched in the oven? :lol:

I believe it is.  Its been the test dial on a bunch of projects.

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rm65453

Awesome work @NCRich

 

 

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GulfGT40

Great reading, you've layed out and worded the process so well that even I'd think about giving it a go. Cheers.

Edited by GulfGT40
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brang1

amazing work, well done. Only wish i had the patience... and smaller fingers

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BabaNJ

Nice one Rich, i order a nh35 to try in one of my budget dj builds but give up after failing to secure the movement with tabs. That gasket idea is neat to make it  fit in case. 

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Theviking

Very nice mod, the 2813 is fucking awful. Thanks for the write up Rich .

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BeyondTheBox

Wow excellent work. I just ordered one of these in blue with the Asian 2836. I know it’s not the accurate beat rate but I like and care more for a smooth sweep than I do for accuracy that almost nobody would knows, and surely nobody could tell in photos. I’m sure you’re right about how dirty it is, and it may need servicing sooner than later, but I’m okay with that for the price. Yours looks great and you do what looks to be awesome work!

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