How to verify NH36 crown position?

[schoolsofthought]

Hi,

I bought an NH36 movement off of EBay, but I do not know how to tell if it's the version with crown at 3 or 3.8.

What is the best way to determine this? I don't want to rely solely on description of product from Ebay.

Any place I see a picture of the movements with both crown positions are dial side up and could look exactly the same to me if they just rotated image. 

So is there a different reference point i can use to determine real crown position? For example, is the center of balance spring usually at 9 o'clock?

[RichardHarris123]

I've never worked on one, so I don't know or fully understand your question.  Does this help? 

[tomh207]

It’s a standard movement, it doesn’t care what position it is in. It has dial positions you need to consider but if you’re replacing a previous piece then that would be ok. Your next problem is potentially the day/date rings. You can move them between seiko movements without too much trouble really.

 

 

[schoolsofthought]

2 hours ago, tomh207 said:

It’s a standard movement, it doesn’t care what position it is in. It has dial positions you need to consider but if you’re replacing a previous piece then that would be ok. Your next problem is potentially the day/date rings. You can move them between seiko movements without too much trouble really.

 

 

So I'm not replacing a previous piece, but was thinking about building a new piece using aftermarket/mod parts. 

So regarding the dial positions point, are you saying the crown position is technically determined by the dial I purchase? 

Also the movement came with day/date rings, so how I do know if the ones I have now are compatible with which dials?

And if it doesn't care what position it is in, why are these movements categorized by crown position on seller sites?

2 hours ago, RichardHarris123 said:

I've never worked on one, so I don't know or fully understand your question.  Does this help? 

Is that photo for a movement with crown position at 3 or 3.8?

Edited April 4, 2023 by schoolsofthought

[tomh207]

The movement is categorised as 3h or 4.5h simply by the day/date rings it has, nothing else really matters apart from them and the dial orientation. If you take a bare movement and put a mark on it somewhere to represent 12 o’clock, doesn’t matter where it is, is it not 12 o’clock whenever the hour hand comes around to that point again? The mechanism has no concept of what time/day/date it is, that is entirely done by the indicating mechanisms we put in place, I.e. dial/date/day information.

 

Tom

[schoolsofthought]

59 minutes ago, tomh207 said:

The movement is categorised as 3h or 4.5h simply by the day/date rings it has, nothing else really matters apart from them and the dial orientation. If you take a bare movement and put a mark on it somewhere to represent 12 o’clock, doesn’t matter where it is, is it not 12 o’clock whenever the hour hand comes around to that point again? The mechanism has no concept of what time/day/date it is, that is entirely done by the indicating mechanisms we put in place, I.e. dial/date/day information.

 

Tom

Ok most of this makes sense, but I'm still confused on day/date rings part.

If you say the movement is categorized by day/date rings, what am I looking for on the day/date rings to know which movement I have?

I think I see it now. I see the day/dates line up if i rotate movement to have crown at 3. If I rotate movement to have crown at 3.8, the day/date wouldn't line up if date window on dial was at 3.

Thanks!

Edited April 4, 2023 by schoolsofthought

[bklake]

The Date lines up at 3 and 3.8.  The Day needs a specific wheel for each orientation.  Seiko slightly change the orientation from true 4 in order to reduce the parts count.  The degrees of change are the same so it will line up in either position.  

With the stem in for orientation purposes, you will see the alignment of the Date wheel at 3 looks correct.  If the Day wheel doesn't look right, it is probably a 3.8.  Rotate the stem to about 3.8 and check if the Day and Date are aligned at about the 3 position.  You can use a paper straight edge to help you visualize the alignment.  Once you have seen it a couple of times, it is easy to spot. 

The inexpensive ebay movements are almost always 3 o'clock Day/ Date and use the grey spacer.  If modding a real Seiko case, you will need the black spacer.  Most of the Aliexpress cases work correctly with the grey spacer.