Reversing movement Seiko NH36

[SwiftyAlex]

Dear watchmakers,

DISCLAIMER: I have no prior watch building/repairing experience, but despite that I did try my best to do as much research I can before hand. The reason I am making a post here is because I could not find any clear information about it and I think a thread like this could help and inspire future enthousiasts.

I want to build a Seiko that runs in reverse. I chose the NH36 movement for this purpose because, because it is a popular movement in the watch modding community. I did find a thread about this on this page:

Basically two options were concluded here. 1. to add a 1:1 gear ratio to make it run backwards. 2. To flip the pallet fork, escape wheel and drive spring.
I don't think just adding a 1:1 gear ratio is something easily done right? To do that I believe I would need to drill a hole for that one specific gear. I am not quite fond of this idea. To me the second option seems better, because I believe these "flipped" parts could be custom built.

So from what information I could collect, I figured I'd need to flip the escape wheel, pallet fork, the winding wheel that is pushed/pulled by the magic lever, and the magic lever's teeth. I could not find the name or part number of this wheel in the partslist unfortunately.

So my questions to you guys are:
- Do you recommend any custom watch manufacturers, I have found and contacted this one already. https://cwrnh.com (Anyone had experience with this one?)
- What do you guys think about reversing a watch's movement and my approach to it?

 

Resources:
FClear movement overview video:

Full service video:

Watch partlist: https://www.timemodule.com/upload/PDF/NH35_TG.pdf

[jdm]

13 hours ago, SwiftyAlex said:

I want to build a Seiko that runs in reverse

Have you ever worked on a watch mov.t before? To be blunt, adding or modifying , 'flipping gears' and the like as if they were hamburgers, is maybe 100 times above the reach and the possibilities of not only a beginner without knowledge, tools and experience, but also surpasses most accomplished watchmakers.

[Nucejoe]

https://wristweargear.com/anticlockwise-watch-what-it-is-and-why-it-is/

[markr]

try using mirrors.

[nickelsilver]

The quoted post said pretty much everything there is to say. Your summary of that post is way off what was said, perhaps read it again.

 

But to briefly re-take it:

New winding pinion and sliding pinion, left hand thread on stem, new crown with left hand thread

Reversed click, possibly requiring new barrel bridge

New barrel arbor, maybe new (or modified) barrel

Reverse fork (potentially [probably] new fork

Reverse escape wheel

 

Or:

Move barrel so it disengages with center wheel

Implement new pinion that engages barrel and center wheel

 

1st case, lots of new parts, probably run fine

 

2nd case, some new parts, 1 extra pinion, the extra pinion will eat 5-10% of available power, and poorly engage gearing-wise as it's dealing with a ~8:10 ratio on one side and 1:1 on the other. Also it will be steel to steel on the 1:1 so lubrication of teeth necessary. It's feasible to try another alloy like hardened copper beryllium to avoid the lubrication issue, but long term it's a no go.

 

If a client asked me for this I would refuse the second option as it's not long term viable (not the first time I've been asked to put an additional pinion between barrels and train- but it wasn't to reverse direction); 1st option would be in 5 figures as a start.

 

[WatchMaker]

You don't have any experience in this field but want to engage a company to build you a reverse watch?

Might be worth purchasing something already done (https://www.ebay.com/itm/Seiko-6309-7290-Vintage-Reverse-Divers-Automatic-Watch-Mod/255421149982 is just an example), seeing how you get on with it and then making any next decision.

[jdm]

A possible reason why some Seiko enthusiast think it's easy to to have the mov.t run backward is because there have been videos of older watches like 6309 , modified like that by a Philippino watchmaker. But nothing is known about how he did that, if it works for more than 10 minutes, or anything else.

[WatchMaker]

1 hour ago, jdm said:

A possible reason why some Seiko enthusiast think it's easy to to have the mov.t run backward is because there have been videos of older watches like 6309 , modified like that by a Philippino watchmaker. But nothing is known about how he did that, if it works for more than 10 minutes, or anything else.

Yes indeed. And there has been a previous discussion on this too which I can see we also both commented in! https://www.watchrepairtalk.com/topic/15292-making-a-watch-run-backwards

I guess my point is that the watch I've referenced does seem to be working; this guy has a good ebay rating; and gives a four month warranty. If it runs and works as it should, but online information remains opaque (I haven't even looked to be fair but noting your comments), then this could be a route for our OP to research around rather than engaging with a company to reinvent a particular wheel (at what cost?!) that's already been solved. Only my thoughts of course.

Edited March 11, 2022 by WatchMaker