NH35A to NH38A swap

Today we are swapping the movement in a Steeldive watch. The watch has no date window but uses a Seiko NH35A movement, which is equipped with a date complication.
Seiko makes a NH variant that would be a better fit for this watch. It is the NH38A. A three hand automaltic movement, hand winding and hacking, with no other complication. It is a direct replacement for the NH35A. All dimensions are the same. let's see how this goes.
‪@JustOneMoreWatch‬ ‪@MyRetroWatches‬
‪@steeldivewatchstore77‬

[@TheDimanoid999]

Danke dir! Genau was ich gesucht habe.

[@HeikosGarage]

You are welcome. Gern geschehen

[@oktc68]

Very useful teaching aid. Want to try this as my first mod.

[@DavidTipsin]

Love this! This thing with ghost date also bothered me. Another great thing about date only movement is that there are no plastic gears inside

[@HeikosGarage]

I didn't even know that. Thanks for sharing

[@EudesRJ]

Probably they got a discount buying huge amounts of NH35 and buying just a few NH38 gets more expensive than simple using the NH35

[@Tunkkis]

Yes, and no sense in going through the extra effort of removing unused complications if they do not inhibit function of the watch.

[@AndreAndre-yd5gw]

You don't get it, because you are not a watch guy.

[@Tunkkis]

@@AndreAndre-yd5gw ?

[@akastenas]

I guess nh35 is a pain for perfectionists it's understandable.

[@EudesRJ]

@@akastenas I’m a perfectionist but don’t care anymore, I just notice the ghost position of my NH35 every 2~3 month when it deviates 5 minutes and I readjust the watch.

[@stefpix]

Great watch, thanks for posting. Are the hour hand and minute hand aligned like at 6 o'clock they make a straight line? that part seem the hardest. Did you use magnifying glasses/loupe?

[@HeikosGarage]

I line up hour and minute at 12 o'clock. I used some loupes.

[@sylus121]

I would like to do the same but replace the nh35a with a pt5000... But it seems like nobody has done this modification before 😅

[@rosstisbury1626]

helpfull many

[@devicentemingo]

Thank you so much for your video! I do have a question, the stem of the nh35 movement will fit on the nh38 movement with no problem, is the same stem?

[@HeikosGarage]

In principle the end of the stem will fit but you will have to adjust the length of the stem. In one of my videos i am showing the process of clipping down the length of the stem.

[@devicentemingo]

@@HeikosGarage Thank you so much!

[@yosefmarkov425]

Great video! Quick question, are all the NH movements interchangeable? Are they all the same size? I'm looking for case options for an NH38 and I'm wondering if I can just use an NH35 case for it.

[@HeikosGarage]

Yes the NH movements have the same overall dimensions. The specs can easily be found with Google. Cheers

[@yosefmarkov425]

@@HeikosGarage thank you so much, I really appreciate the quick reply!

[@niltonbatistajunior9731]

great video! I bought a PD-1964 with an NH35 and want to replace it for a NH38 just like you did. my only fear is about the threaded crown.

[@HeikosGarage]

Most likely the stem will be the correct length. I don't think I had to shorten mine. It is really not too difficult. There are some great videos out there that explain how to get the stem the perfect length for a screw down crown. Go for it. It makes the watch unique and truly yours. Gets rid of that pesky ghost position.

[@shaggy01985]

Use a piece of rodico to stick the hands to it. So you can manoeuvre the hands more easily and put them on faster.

[@HeikosGarage]

Thanks for the tip.

[@sasmitha8446]

The crown sticks out a fair bit, is there no need for a crown stem shortening?

[@HeikosGarage]

not in this case. I checked. I am still wearing this watch weekly and the stem and crown engagement is perfect.

[@Alputherock]

Hi , ich habe das Werk ausgebaut und ich hatte plötzlich einen geriffelten Metallring in den Händen , hast du eine Ahnung wo der hingehört , wird er ins Gehäuse eingelegt und dann kommt das Werk drauf? Oder kommt das Werk rein und dann dieser Ring ?

[@HeikosGarage]

Wie groß ist denn dieser Ring?

[@dagobaker]

out of the box my steeldiver 1970 with nh35a is 4 seconds a day fast and 1.2 beat error... should i open it up and try and improve?

[@HeikosGarage]

If you have a timegrapher you definitely could try. Good luck. Don't forget, even if it goes sideways, the movement only costs around $30.

[@thegorn]

Yes because that beat error is too big

[@djdelarosa25]

Is there any way to mod the NH35 to remove the 1st crown position?

[@HeikosGarage]

I would not necessarily see the need to mod a $28 movement but I bet it is possible.

[@Cuccos19]

Is it possible, to exchange the Epson YN55 movement with the Seiko NH38? If I understand well, the Epson YN55 movement basically identical to the Seiko NH35. I just don't know is it stand for general features - parts/construction and working/accuracy - or also the exact dimensions too?

[@HeikosGarage]

Not sure. Good luck.

[@BanksProject]

I would really like to have my movement changed out, do do you ever take viewers watches and repair them. I would give you the NH35 after you swap. I also would buy the NH38 and send it to you with the watch.

[@HeikosGarage]

I guess we can do that. I have an email address in my channel about section. Email me and we will figure it out.

[@wannabe_sailor_777smith6]

Why didn’t you just swap the dial with a date aperture?

[@HeikosGarage]

I was going to keep that watch as non date and use the nh35 for another build.

[@glenh4971]

The NH35A is a great movement. So is the NH38. I have both. The NH35A is cheaper in price. This is why it is in all the cheaper watches on Aliexpress. Unless I needed the extra movement I would not have changed it out.

[@HeikosGarage]

Of course it wasn't necessary but one is a $25 movement the other is a $28 movement. Now my watch doesn't have the ghost position anymore and that actually makes me like the watch more.

[@shiraz1736]

Glad to know, I won’t be using Landfill Express for my watch purchases.

[@geoffreykoo5266]

The reason is manufacturer try to keep the cost low. NH35 cheaper than NH38,also it works on both date dial and non date dial.

[@joekelly9369]

Absolutely , steinhart buy ets movements by the pallet load , its business , im sure rolex do it with their eagler movement suplier

[@ccooper8785]

Could you have fitted the VH31 mecaquartz movement instead ? It is the movement that should have been fitted IMHO... (it is 2022 after all) 😃

[@HeikosGarage]

Buying a automatic watch to then put a quartz movement into it would kinda defeat the purpose. The attraction of mechanical device is just that, they are mechanical and don't use modern ICs or circuitry.

[@stefpix]

@@HeikosGarage Some Steeldives are available with VH31 and NH35. On an inexpensive watch it is nice to have a quartz movement with a sweeping hand. Less thing can go wrong with a quartz watch, if used as a beater during sport activities, an automatic movement is more delicate. Where I live, NYC, watchmakers charge $300 to service an automatic watch. A quartz can be an attractive option.

[@AndreAndre-yd5gw]

Quartz needs yearly battery replacement and I don't like unnecessary expenditures. I learned to service my own automatic watches. A good automatic tool watch is like the old air cooled beetle. Ultra reliable and with little maintenance runs for ever.

[@stefpix]

@@AndreAndre-yd5gw that's great you learned the skill. It must be quite complex. There is always the risk of breaking something. How do you prevent dust from getting in the movement? Any videos you suggest?

[@overlandmotorcycletours4785]

If building a watch and using a NH35 and using a dial without a date window, you can remove the calendar works/ date disc from the NH35.

[@evka3220]

What is the difference between nh35 and nh35a?

[@HeikosGarage]

Not sure. The NH35 is the version of NH movements with a date complication. Nh35a? Check this out. calibercorner.com/seiko-nh-caliber-differences/

[@evka3220]

@@HeikosGarage I cannot really find somewhere the difference. Day and day/date comes with nh35 and nh36 respectively. I think the a in every nh version has to do with different thickness?

[@carlodelavera9735]

Why did you get a whole new movement when the NH35 can be moded to the NH38?

[@HeikosGarage]

I took the nh35 out and used it in a different project

[@carlodelavera9735]

@@HeikosGarage ah makes sense!

[@SK-2175]

I think the only reason why you want to change the NH35 movement to the NH38 is to view the balance tickling at the 9 0'clock. With a dial without the window at the 9 o'clock , there is for me no reason to do it.

[@HeikosGarage]

The reason for me is that the nh35 actually has an installed date wheel and a crown position for setting the date but this watch doesn't have a date window. Secondly, i am replacing it because I can and i will use the nh35 movement in another project.

[@juimecoloma7090]

Lo estoy remplazando "porque puedo# 🤣, que respuesta más llena de contenido😂

[@lesinskas1827]

I think they 35A, becouse its cheaper cheaper than 38B

[@zacharyhastings8304]

I would not recommend this swap for those with threaded/screw-down crowns as the stem travel to set time is minimal (calipers suggest

[@HeikosGarage]

I think that a stem length adjustment (cutting) could be necessary but that a nh38 is incompatible with a watch that accepts a nh35 is unlikely. The movement of the crown to be able to screw it against the case is not done by stem movement but by the spring loaded movement of the crown along it's attachment point. In the unscrewed position the backside of the crown needs to line up perfectly with the tip of the threaded tube that protrudes from the case. Give it another try and see if there is a gap between the Crown and the tube i mentioned.

[@HeikosGarage]

Zachary, If you like, you can send your unimatic watch to me. I pay for the nh38 and I will put into your watch and make it work. Of course I would make a video out of it. Let me know what you think.

[@carlodelavera9735]

The nh36-35-38 are all the same except for the date complications. it is imposible for an nh38 not to fit where an nh35 was. NH36 and 35 can be easily moded to become nh38 by removing the date complications, I have done that many times. the reason for your issue is not the movement but the stem length.

[@WillyMcCoy50]

​@carlodelavera9735 removing the date complication is only halfway to making an NH35 into an NH38. You would need a two position setting lever.