Wanting to replace Seiko 7S36 with NH36 movement

[jolax]

Hi guys,

I am trying to replace the movement in my Seiko SNZF17J1 which has 7S36 movement with NH36 movement. First, this is my first attempt doing this since I had damaged the movement while regulating it. I figured since the 7S36 is a non-hacking movement, I might as well replace it with NH36. Before I embark on the process I would like to know what are the things that I need to be prepared for. First I know that I need to change the date wheel since my watch has black date wheel while the NH36 movement I bought is white. I think I can do this part which I have seen the video on youtube. I have also bought a few tools with me such as watch repair set screwdrivers, watch movement holder, tool set remover, hand pressing tools, case opener and may buy more tools as needed here. If you can suggest what other tools I need, please let me know here. 

A few questions here:

1) Do I need to change the dial spacer from the old movement?

2) Is the stem different from the 7S36 to the NH36?

3) When installing second hand, is it better to install when the watch is in stop position? I have seen people installing it while it is engaged/moving.

Thanks in advance and looking forward to hear from you all watch hobbyists!! 

 

 

[jolax]

Oh also I wanted to add that I have the tweezers, magnifications lens, rodico in my arsenal...lol

[spectre6000]

1) I think what you're calling the dial spacer doubles as a movement spacer here. I believe they're interchangeable from the movement's perspective, but potentially not as much from the case's perspective. To wit, I have an NH39 that I'm confident will be a **BLEEP** and a half to extract from the case when I eventually need to do so.

2) Yes. You'll need to cut the new stem to fit the case, clean up the threads, apply some loctite, then install your crown. 

3) It doesn't hurt, probably better if you do, but it's not strictly necessary.

[jdm]

  On 5/15/2021 at 2:43 PM, jolax said:

1) Do I need to change the dial spacer from the old movement?

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Not unless you're swapping from/to a diver watch, to a non diver. The spare ring on the latter is marginally thinner.

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2) Is the stem different from the 7S36 to the NH36?

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Yes.

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3) When installing second hand, is it better to install when the watch is in stop position? I have seen people installing it while it is engaged/moving.

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Yes, as that tell syou it's straight on, and ready to be pressed down.