# Modding a GMT watch to 24-hour?



## ned-ludd

_WARNING: If you abhor modification of watches, please do not read this or criticise the idea simply because you don't approve._

The market for pure 24-hour watches is limited so there's not a lot of choice out there. Pure 24-hour mechanical movements seem to be the sole domain of the high end manufacturers like Breitling, Sinn and Glycine, or more mass market manufacturers like Raketa and Vostok.

I've noticed that makers of low and mid-range 24-hour watches - like No-Watch, Mr Jones and UNO - simply use 'GMT' movements and omit the 12-hour hand. Movements like the mechanical Seagull 2557 and quartz Ronda 515.24H are cheap, readily available and are to be found in the majority of watches presented as 24-hour models.

This led me to thinking that if one craves more variety in watches of the 24-hour type one could use suitable existing GMT models and simply remove the 12-hour hand from them. GMT watches that lend themselves to this would need to have 24-hour marks on the dial and no 12-hour marks. I've found numerous current, inexpensive watches that I believe would lend themselves to this modification. For example:

* Seiko Criteria SLT083, SLT10x
* Seiko Prospex SUN0xx
* Timex T2P42x
* Citizen Promaster GMT BJ7081-51E
* Parnis Military GMT (Seagull 2557)
* Invicta 6988

Removing the 12-hour hand from a watch is easy but merely eliminates it as a visual distraction. A watch without an obvious hour hand and a differently shaped or coloured GMT hand may just look broken. Replacing the GMT and minute hands with a matching pair would be the obvious thing to do and is within the capabilities of many amateur watch repairers. The result would be an aesthetically and functionally passable 'pure' 24-hour watch.

The trick to replacing the hands, of course, is finding ones of the right size or modifying existing hands to fit. That may prove to be the biggest obstacle to doing so, especially given how difficult it seems to even get hand measurements for the various GMT movements found in the candidate watches.

It could be argued that this modification may confuse the casual observer but given that most casual observers are already confused by 24-hour watches that's not a problem. For many 24-hour enthusiasts that's probably part of their appeal!

I have already acquired a couple of GMTs for experimentation. It will be a challenge but it keeps me entertained and off the streets.


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## mougino

Interesting project!

Good luck and keep us posted about your progress!

Nicolas


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## calcisme

Some of the Glycine Airman watches come as GMT or purist versions and do exactly what you mention about. At least that is my current understanding.


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## wemedge

I've had this modification done twice before- one was a Steinhart GMT, with the 12-hr hand simply removed, and the other was a Glycine Airman GMT which was converted to purist by Werner Siegrist.

I ended up having the Steinhart returned to its original state eventually, but kept the Glycine as purist.


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## ned-ludd

wemedge said:


> I eneded up having the Steinhart returned to its original state


That's part of the beauty of it: any watch with removed or replaced hands can be restored easily to its original state.


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## ned-ludd

I now have several candidates for my conversion project. Each of these I've had to buy new because I can't find any second-hand ones. I bought four GMT quartz watches: a Seiko Criteria SLT083, Citizen BJ7070-57E, Seiko SUN069 and a Timex T2P424.

This is a good selection for a collector because they're all functionally different: one has a compass bearing bezel (handy for New Earth Time), one has an E6B flight calculator, one has a world time bezel and one has a 24-hour bezel. Also, one is a perpetual calendar, one's solar powered and one's kinetic powered. As to the uniformly black faces, stainless steel cases and bracelets, well I just prefer that in a watch.

The Timex T2P424 is a handsome watch; it offers three time zones (love that 24-hour bezel!) and a really cool Indiglo face. Sadly, however, it's not a candidate for conversion due to its mode of operation. 

 Every press of the button at 2 (04) o'clock moves the GMT (24-hour) hand forward by thirty minutes. If converted, in normal use it would be too easy to accidentally bump that button and thus lose track of what hour it was.
 When you pull the crown out to adjust the time, the GMT hand moves to the 12 (24) o'clock position. This means setting a converted watch correctly would require rotating the minute hand until the date ticked over (i.e. 24:00) and then counting full revolutions until the desired hour is reached (there being no 12-hour hand to guide you), then pushing the crown in and moving the GMT (24-hour) hand into place using the button at 2 (04) o'clock.
I'd love to keep the Timex but if it can't become a 24-hour watch it has no place in my collection; I have to sell it.

So three watches are for the 'chop' but as they're brand new I'm frightened of wasting good money by breaking them so I've chickened out on doing the conversions myself. As soon as time and budget permits I'm going to take them to my preferred watchmaker to get him to do the job.


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## Steve24h

I've been thinking of doing exactly this as well.. the 2431 based Vostok's automatics look like they could be a good candidate, but some would need a new dial which makes it practically impossible... unless anyone knows where to make custom dials?


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## r-gordon-7

I'm interested in converting a 24 hour watch with a rotatable "diver/timer" bezel to a two time zone 24 hour watch by replacing the "diver/timer" bezel with a 24 hour bezel. The watch - a Russian Vostok Komandirskie K-35, which I have...









The bezel... I've seen a few rotatable 24 hour bezels that supposedly will fit the watch (and I even have one), but so far haven't found the one I want to use... I have a rotatable thin stainless steel 24 hour bezel that should fit...







However, ideally, I'd like to find one shaped & sized more like the watch's stock rotatable bezel, but with 24 hour markings. If that's not possible, I'd like a rotatable bezel with a ceramic insert but with white 24 hour markings (so, far the only one I've seen that I know is properly sized to fit is black with yellow markings and I don't think yellow markings would go well with the watch's dial face). Ideally, I'd like the ceramic bezel insert's background to be black/blue - black for the "dark" hours of 6-18 and blue for the "daylight" hours of 18-6... I'm still looking for such a rotatable 24 hour bezel/ceramic bezel insert combination that will fit the watch, but eventually I may settle for the thin stainless steel 24 hour bezel I already have...


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## ned-ludd

View attachment 12425071


That looks like a Vostok 100 case (just like mine). I've always thought that bezel's edges sharp enough to draw blood if given half the chance. To soften it, perhaps a Murphy Manufacturing VO1060 bezel would suit? Then a Seiko SKX007 24 insert (from yobokies or elsewhere) would finish the job. Getting a colour and font to suit the face (mine's black, BTW) could be difficult. Personally I'd just go for a black/white 0600-1800 split to keep things simple.

It's certainly something that's been done by others and if I didn't have so many other projects on I'd try it myself. Maybe later.


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## r-gordon-7

Thanks, ned-ludd for the lead to Murphy Manufacturing. I've now contacted & been in touch with Dave Murphy, trying to figure out whether their VO1060 (or perhaps their VO150, though that one's currently out of stock) bezel would actually fit the Vostok Komandirskie K-35 - preferably with a DLWwatches "Ceramic Bezel Inserts - GMT Batman Bezel Insert" for Seiko SKX007 (https://www.dlwwatches.com/collecti...s/products/ceramic-bezel-inserts-gmt-batman-1). I've also been in touch with Damien at DLW. Both have been very helpful & prompt to respond, but apparently none of this is quite as simple a determination or as definitive as it might seem. So, though I'm usually not a gambler, I may have no choice but to take a shot by ordering the parts that are "most likely to work" - and then see if in fact they do... (Or maybe just install the Meranom stainless steel 24 hour bezel I already have that I believe is supposed to fit...?)


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## steeviee

I still have the MLV I bought off you! It has become my favorite watch. I have since purchased a D24-09 but that watch is uncomfortable on the wrist and by the end of the day I can't wait to take it off. The Airman MLV is perfect!


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## ned-ludd

At the risk of hijacking my own thread...

I think my attempt at replacing the bezels on two K-35s has been successful. These are now much more fetching than they were with the original bezels.

The bezels and inserts were bought on eBay. I just looked for bezels that fit the K-35 and inserts that were for Seiko 6xxx. The glue is rubber cement from a $2 bicycle tire repair kit.


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## Steve24h

That looks amazing! now you're really getting me excited about doing some of this!


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## ned-ludd

This is not going well.

The watchmakers I have approached thus far to help me modify my GMTs have refused point blank to help. At first they don't understand why I want to modify the watch, then they say they don't modify watches because the watch companies won't let them. Then I ask for help in sourcing replacement hands and they pretty much show me the door.

So I'm on my own.

I've already abandoned the Seiko Kinetic as a candidate. This is because I've discovered that you can't own a kinetic if you don't wear it frequently because it takes too much effort to charge up. (They're also _so_ noisy!)

The Citizen is the watch I most want to modify but it needs its hour hand hole size increased and I'm not sure I can do that easily or without breaking it. I seriously doubt I'll be able to find off the shelf hands that will suit.

Having stared at the Seiko Criteria countless times over the last six months I think it would work with the existing orange GMT hand so just removing the hour hand may be enough. But I'm no longer sure it will be worth it.

Call it sour grapes if you will but overall I'm going off the whole idea. Since my last post here I've been modding various watches to 24 hour 'regulators' but it feels like I'm doing that just because I can, rather than because I want to wear them. GMT mods may be a bridge too far beyond that.


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## ned-ludd

Today I bit the bullet and removed the 12-hour hand on my Seiko Criteria SLT083. I think it looks okay and makes sense.








I almost got the second hand aligned correctly but know better than to keep retrying it. It's close enough; actually closer than some of my other quartz watches as received from their makers!
Setting the perpetual calendar is also an interesting exercise, I must say.


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## TOPAZ

ned-ludd said:


> Today I bit the bullet and removed the 12-hour hand on my Seiko Criteria SLT083. I think it looks okay and makes sense.
> I almost got the second hand aligned correctly but know better than to keep retrying it. It's close enough; actually closer than some of my other quartz watches as received from their makers!
> Setting the perpetual calendar is also an interesting exercise, I must say.


The watch looks like SEIKO has produced it just like that.
Well done !

regards, Michael
b-)


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## pithy

GMT aside, going from 24 hour to 12 hour is fairly straightforward.

The inverse isn't.

It's a geometry thing.


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## ned-ludd

Well, it looks like I broke the SLT083, most likely from being too heavy-handed when pressing the minute and seconds hands back on.

Several days afterwards the watch stopped a few times both when sitting and when being worn, so I have been recording the stoppages. Over the past week the watch (sitting on a bench) has stopped at these times and in these positions.

2018-02-17 07:46:44 Face Up
2018-02-21 21:17:44 Crown Down
2018-02-23 09:17:44 Crown Down
2018-02-24 09:17:14 Face Angled Upright
2018-02-26 09:17:51 Face Up

Previously a simple shake got it started again but this morning it took quite a few shakes. It stopped every few seconds for about fifteen seconds but has been running since then.

I knew and accepted it was a risk doing this modification but it's nevertheless a disappointment.

It's a very new watch but obviously I've voided the warranty. I'm not sure if it will be worth the cost of getting it professionally repaired and I'm afraid that if I do, the repairer may insist on replacing the 12-hour hand, thus bringing me back to where I started. I would attempt the repair myself but doubt that I could get the parts. Repairing a friend's watch on which I found that the hour wheel had lost a tooth it was easier and cheaper to replace the entire VX3L movement, which I did successfully (it's been keeping perfect time for the six months since then). It doesn't, however, seem likely that I'll be able to find a replacement 8F56 movement or suitable substitute for the SLT083, since the 8F56 is discontinued.


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## shock6906

I'm interested to know if anyone has a tech sheet on the Seagull 2557 movement. I've got a watch project that needs a movement and it's one of the only ones that fits the most minimum of criteria, which is having the functions I need and in the right place. The next challenge is seeing if the dimensions are a match.

For anyone interested, I picked up a Zenith Elite GMT dial and I'd love to be able to put a movement behind it.


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## RobFedorafield

ned-ludd said:


> At the risk of hijacking my own thread...
> 
> I think my attempt at replacing the bezels on two K-35s has been successful. These are now much more fetching than they were with the original bezels.
> 
> The bezels and inserts were bought on eBay. I just looked for bezels that fit the K-35 and inserts that were for Seiko 6xxx. The glue is rubber cement from a $2 bicycle tire repair kit.


I'll have to keep my eye out for one of these K-35's I really like the design.


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## Ipse

ned-ludd said:


> At the risk of hijacking my own thread...
> I think my attempt at replacing the bezels on two K-35s has been successful. These are now much more fetching than they were with the original bezels.
> The bezels and inserts were bought on eBay. I just looked for bezels that fit the K-35 and inserts that were for Seiko 6xxx. The glue is rubber cement from a $2 bicycle tire repair kit.


Wait, you glued the bezels in place? I was looking at the same mod if I decide to get one of the 24h Komandirskie, but I want the second time zone to work - i.e. rotating bezel.
This would be a fairly simple mod that this novice can attempt


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## ned-ludd

Ipse said:


> Wait, you glued the bezels in place?


I glued the inserts into the empty bezels, which still rotate.


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## JAEGER003

Howdy!

I'm cross-posting this thread: https://www.watchuseek.com/f5/vostok-komandierskie-650541-mmw-01-a-4658657-2.html

Basically -- given that the Vostok K-35 and variants are about the only affordable (read: cheap) automatic 24-hour movements on the market today, why aren't there more modding options like there are for the SKX007 (e.g., Dagaz, Yobokies).

I have a thing for noon-top 24-hour watches but they're obviously rare. Finding an automatic even moreso... and dammit, I don't like any of the options relative to the cost (e.g., Ocean7).

I have a couple already (Yes Zulu, LumTec B34/37) but they're quartz. I have a K-35 with two critical flaws: (1) it's midnight-top, and (2) a lume pip fell off.

How hard is it to 3D print a watch dial? (And apply lume?)

--Jaeger


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## ned-ludd

JAEGER003 said:


> How hard is it to 3D print a watch dial?


Given how thin dial plates need to be and the nature of consumer-grade 3D printing (at least the filament extrusion kind) I'd say it would be very hard indeed. The risk of the plate cracking under even moderate handling would be too high. Also, the detail and finish would probably not be good enough for a presentable watch. Fine for prototyping, though.

You might do better with stereolithography but would need a very good printer. A resin dial plate of around 1mm thickness would probably still be very fragile, though.

I've been pondering dial design and backyard fabrication for some time and have concluded that the only options for an amateur are CNC engraving with a router or laser. With these you would start with a metal dial blank and impose your primary design onto it, then paint or enamel the remainder of the design (including lume). Again, though, the detail and accuracy of the CNC device needs to be sufficiently high for an acceptable result.

For some time my CNC router has been giving me grief with inaccuracy on the Y-axis so instead I've been doing all my CNC engraving and cutting on my laser cutter. A while ago I bought some special spray that enables laser engraving onto metal and when the weather cools down I hope to resume my activities in this area. When I do you can be sure a few watch dials are on the list of things to try out.


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## JAEGER003

ned-ludd said:


> Given how thin dial plates need to be and the nature of consumer-grade 3D printing (at least the filament extrusion kind) I'd say it would be very hard indeed. ...


Gah, was afraid of that. I thought of 3D printing and thought "oh, it CAN'T be that easy, can it?"

Guess not. 

What about stripping the existing stock face and re-imaging that? Keep the same substrate but either get a super-hi-rez printout and shellac it down...?

--jaeger


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## ned-ludd

JAEGER003 said:


> What about stripping the existing stock face and re-imaging that? Keep the same substrate but either get a super-hi-rez printout and shellac it down...?


I'm sure that will work: there are plenty of frankenwatches out there with inkjet and worse dials that fool people unless they look closely.

The best smartwatches are less than 300dpi so I expect you would be okay with a 1200dpi print. Use the thinnest archival paper or mylar you can get so the dial doesn't become too thick. Or print on stiff card or mylar and replace the dial altogether. I find that dial dots do a very good job of holding things in place.

Here's an A5 PDF of a very very simple 44mm 12-up dial printed at 1200dpi. Have a play!


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## JAEGER003

ned-ludd said:


> ...Here's an A5 PDF of a very very simple 44mm 12-up dial printed at 1200dpi. Have a play!


Cool! Thanks! 

OK, now the question is whether I can find a "donor" dial so I don't have to mangle the one I have.

Then again, the one I have lost the lume pip from the 2200HRS position -- it's just bouncing around behind the crystal, which while minor is absolutely maddening. I'm going to brave opening the case just to get it out. Not sure if I'll try reattaching it, but it can't be lose in there.

Regardless, the watch itself is so cheap that I figure it's a good candidate for "experimentation." It's not worth taking it to the shop! I mean, for < $100 delivered...! To wit: https://meranom.com/en/komandirskie-classic/35/ ... 

Side note: should you get one of the K-35s, I recommend the non-date face. There's no quick-set so it's a PITA if you let it run down.

--Jaeger


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## ned-ludd

JAEGER003 said:


> Side note: should you get one of the K-35s, I recommend the non-date face. There's no quick-set so it's a PITA if you let it run down.


It's been some time since I bothered to set the date on my Vostoks. Even on mechanical watches with quick-set dates I tend not to bother. Wearing each of them no more than a few times per month means they spend much of their lives run down anyway.


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## Carl.1

Appreciate the thread is on modding, but these are a good 24 hr, and not overly expensive.
https://ocean7watchco.com/collections/24-hour-watches


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## ned-ludd

A rather scruffy old Romanette 2000 GMT with Shiojiri VX39 movement successfully converted to pure 24 hours.















The original hour hand's hole couldn't be enlarged because its flange was too small, so I replaced it with a similar one that could.
The lume on the new hour hand is sadly not quite the same colour as the original.
The VX39 has a 0.65mm minute shaft and I had no hands that would fit so I had to keep the original.
Second hands give me endless trouble so I didn't even try to replace that.


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## ned-ludd

After my Seiko SLT083 GMT conversion resulted in a randomly-stopping watch I concluded that I'd broken the 8F56 movement. A search for a replacement movement took a while but eventually I found a cheap enough one in a battered old SLT009 GMT at a pawnbrokers.









I let that donor watch sit on the bench for a few weeks to make sure it worked but then, being terrified of breaking another movement, decided against doing the swap myself. Then I was between jobs and didn't really have the funds to get a watchmaker to swap the movements so the whole project was put aside.

In early July I started another job which is currently based in Kogarah - a suburb south of the Sydney CBD I don't recall ever visiting before. Throughout the first week, though, a little voice in my head kept saying _"You know something about Kogarah"_ and it took me a while to remember what that was.

In my searches for watchmakers in Sydney I would occasionally read of a 'Mr Watchmaker Van Le'. He's a Vietnamese watchmaker who operates out of a tiny little portable booth on the street outside a shop in - Kogarah! Here's a photo someone took of him at work in 2006.















It happened that he was only one street away ('Near fountain outside the library') from where I am now working so I went on a Tuesday morning to have a look. He's still there and still plying his trade, though looking much older than in the photo taken twelve years earlier. I decided to give him a try, as much for the novelty of dealing with a 'quaint street vendor' as anything else: it's not something you encounter much in Australia.

I presented the SLT083 and the replacement movement and described what I wanted done and he said _"I do that for thirty dollars but I tired now. You come back at 3."_ I went back at 15:30 and he'd done the swap but had had to replace the battery. He still only wanted $30. I'd told him not to worry about setting the perpetual calendar because I could do it myself and he asked if I had instructions for that. _"You give me copy?"_ I told him I'd be glad to.

I went back on Thursday (he doesn't work on Wednesdays) and gave him printouts of the calendar setting instructions. By then the SLT083 had been randomly stopping again - just like before - and was now in two-second (low-battery) mode. We discussed that (within the limits of a language barrier) and I told him I was glad to know that I hadn't broken the original movement, suggesting that it must be removing the 12-hour hand that makes it misbehave. He critiqued my previous work and showed me how I should be setting watch hands. He also suggested a completely fresh battery, just in case.

Saying he was happy to give me advice and instruction on watch repair because _"you good man and give me paper" _we shook hands and I left but I think I've made a friend.

Having happily discovered that I hadn't broken the original movement I reassembled the donor SLT009 with it and replaced the batteries in both watches. Then I left them both on the bench side by side, occasionally changing their orientation to see if they'd stop. After a week of this, both watches were still running and keeping good time so I finally bit the bullet and have been wearing the SLT083 all day and it hasn't stopped. The SLT009 is also running fine.

I'm still rather baffled as to the real cause of the random stopping. I'll keep a supply of CR2412 batteries handy anyway, just in case it's simply battery trouble as Mr Van Le suggested.


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## mougino

ned-ludd said:


> After my Seiko SLT083 GMT conversion resulted in a randomly-stopping watch I concluded that I'd broken the 8F56 movement. A search for a replacement movement took a while but eventually I found a cheap enough one in a battered old SLT009 GMT at a pawnbrokers.
> 
> View attachment 13323007
> 
> 
> I let that donor watch sit on the bench for a few weeks to make sure it worked but then, being terrified of breaking another movement, decided against doing the swap myself. Then I was between jobs and didn't really have the funds to get a watchmaker to swap the movements so the whole project was put aside.
> 
> In early July I started another job which is currently based in Kogarah - a suburb south of the Sydney CBD I don't recall ever visiting before. Throughout the first week, though, a little voice in my head kept saying _"You know something about Kogarah"_ and it took me a while to remember what that was.
> 
> In my searches for watchmakers in Sydney I would occasionally read of a 'Mr Watchmaker Van Le'. He's a Vietnamese watchmaker who operates out of a tiny little portable booth on the street outside a shop in - Kogarah! Here's a photo someone took of him at work in 2006.
> 
> View attachment 13323005
> View attachment 13323003
> 
> 
> It happened that he was only one street away ('Near fountain outside the library') from where I am now working so I went on a Tuesday morning to have a look. He's still there and still plying his trade, though looking much older than in the photo taken twelve years earlier. I decided to give him a try, as much for the novelty of dealing with a 'quaint street vendor' as anything else: it's not something you encounter much in Australia.
> 
> I presented the SLT083 and the replacement movement and described what I wanted done and he said _"I do that for thirty dollars but I tired now. You come back at 3."_ I went back at 15:30 and he'd done the swap but had had to replace the battery. He still only wanted $30. I'd told him not to worry about setting the perpetual calendar because I could do it myself and he asked if I had instructions for that. _"You give me copy?"_ I told him I'd be glad to.
> 
> I went back on Thursday (he doesn't work on Wednesdays) and gave him printouts of the calendar setting instructions. By then the SLT083 had been randomly stopping again - just like before - and was now in two-second (low-battery) mode. We discussed that (within the limits of a language barrier) and I told him I was glad to know that I hadn't broken the original movement, suggesting that it must be removing the 12-hour hand that makes it misbehave. He critiqued my previous work and showed me how I should be setting watch hands. He also suggested a completely fresh battery, just in case.
> 
> Saying he was happy to give me advice and instruction on watch repair because _"you good man and give me paper" _we shook hands and I left but I think I've made a friend.
> 
> Having happily discovered that I hadn't broken the original movement I reassembled the donor SLT009 with it and replaced the batteries in both watches. Then I left them both on the bench side by side, occasionally changing their orientation to see if they'd stop. After a week of this, both watches were still running and keeping good time so I finally bit the bullet and have been wearing the SLT083 all day and it hasn't stopped. The SLT009 is also running fine.
> 
> I'm still rather baffled as to the real cause of the random stopping. I'll keep a supply of CR2412 batteries handy anyway, just in case it's simply battery trouble as Mr Van Le suggested.


Great story, and a happy ending  congrats to Mr Van Le for being such a good man! The world needs more like him.

Nicolas


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## PanKorop

No time today to post a photograph, but here's a link to the Spanish forum Relojes Especiales (12E) with an identical watch. They originated this forum special order, for a 200 watches run.
https://www.relojes-especiales.com/foros/relojes-rusos/vostok-baikonur-con-bisel-modificado-436891/
The owner even adapted the exact same custom bezel from Dmitry Persidsky.
Pull the regular hour hand off, and you get a *24h GMT regulator!* 200m wapro with a moderate 41x46mm case.
What do you think, Mr Buyalov?

I'm tempted now... but maybe it's better I don't have the required tools, skills nor patience 

There are other dual-time Vostoks, notably from the RE series. However, most won't fit that stripping mod, as most have a 12 hour scale, or just the 12 and 6 in the Japanese fashion.


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## ned-ludd

Here's an Invicta Quartz GMT 12226 that has lost its 12-hour hand.










I don't think it looks too wrong and it's fairly obvious what is intended.

To set this watch without the 12-hour hand cue you pull the crown to position 2 and wind the minute hand all the way to midnight - when the date ticks over - then wind it forward as many revolutions as there are hours from midnight to the current time. The GMT/24 hand doesn't move at all while you're doing this; hence the need to count the hours as the minute hand makes complete revolutions.

The GMT/24 hand is set independently by the button at 2/0400: you pull the crown to position 1 and press the button to move the hand into place by small increments (or press and hold to move it faster). Because of this you're better off setting the time on or near the hour so you can position the hand more accurately.

The date is set in the usual fashion of rotating the crown clockwise in position 1.

_Maligned Invicta_​_Is really quite elegant._​_Oops! Lost the hour hand!_​


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## ned-ludd

PanKorop said:


> Pull the regular hour hand off, and you get a *24h GMT regulator!*


Here's the watch in question (and it's a very nice one).









I would not consider this GMT watch a suitable candidate for conversion as it has no 24-hour markings on the dial. This means that the bezel is the only way to tell 24-hour time. What happens when the bezel rotates? You'd have to rotate it back to zero position every time you read it, which would be distracting and, eventually, become irritating. You could resort to gluing the bezel in place but that seems a waste and against the whole purpose of bezels.

Without 24-hour markings on the dial this watch is like hundreds of other GMT watches (ignoring the seconds subdial for now). People are used to the markings on bezels being secondary to the dial, so the absence of 24-hour dial markings on a converted watch would leave no obvious clues that it is now a 24-hour watch. This is most likely why you rarely, if ever, see this style of GMT converted. (Not that it's a common activity in the first place!)

Also, regulator watches have three separate hands on three separate subdials. If you remove the 12-hour hand on this watch you wouldn't end up with a regulator because the 24-hour and minutes hands remain together on the one subdial.


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## PanKorop

ned-ludd said:


> Here's the watch in question (and it's a very nice one).


You mean... this one, right?









I certainly agree it's a fine watch :-d They look pretty close. It seems they differ on two points:
1) Here is #15/200 and I dare hope yours is different.
2) The custom bezel seems familiar (tks D. Persidsky, eBay pers184), yet oddly opposed... Seriously, I prefer the sun at noon being up in the sky - and the dial. Maybe it's a French bias, as we use the exact same word to say noon (midi) and the South (le Midi). Anyway, much easier up here for compass watch orientation. Now, of course, if you live "down" in Australia, Mozambique or Angola, where at noon the sun points to the North... it's the same setting, except now 12:00 points to the North ;-)



ned-ludd said:


> I would not consider this GMT watch a suitable candidate for conversion as it has no 24-hour markings on the dial. This means that the bezel is the only way to tell 24-hour time. What happens when the bezel rotates? You'd have to rotate it back to zero position every time you read it, which would be distracting and, eventually, become irritating. You could resort to gluing the bezel in place but that seems a waste and against the whole purpose of bezels.


If your bezel slips inadvertently, then it's unproperly adjusted. It may be time to make the cheapest of all mods: get a good spring from eBay seller "bandukh", a huge bonus over the stock one. This way, mine stays put, never slipping inadvertently (motorcycle jacket rough sleeve and vibrations included), and I readjust it rarely - only for true solar time to take compass readings. As I haven't yet removed the standard hour hand (will I?), the bezel usually just stays put at true solar time... I agree one shouldn't glue it (what a strange suggestion!) as this time varies, esp. when switching on/off daylight saving time.



ned-ludd said:


> Without 24-hour markings on the dial this watch is like hundreds of other GMT watches (ignoring the seconds subdial for now). People are used to the markings on bezels being secondary to the dial, so the absence of 24-hour dial markings on a converted watch would leave no obvious clues that it is now a 24-hour watch. This is most likely why you rarely, if ever, see this style of GMT converted. (Not that it's a common activity in the first place!)


Hundreds? Well, find me those who let you choose at will between 24:00 down or up. Those hundreds you tell about mostly have a date window, and a fixed, inside scale. So the Baikonur may be not all that commonplace.
The outside hour scale doesn't bother me: as if the skinny azure hand pointing as close as possible to the bezel wouldn't be enough of a hint about where to read the 24 hours. What stands out are the minutes. Now, habits? 99% of the people, including quite a few with interest in watches, are just not _used_ to read 24h dials...
Beside, a one-off personal mod is that: a personal - bespoke - choice, so doesn't give a dam of how the average consumer will perceive it. If a project ends up as mainstream, why bother?
As for world "GMT" time, I know I'm offset from Greenwich +2, NY, Toronto +6 hrs, Tokyo -8, etc. and it is math I can handle without pen nor smartphone... no need so far to turn the bezel. Maybe in a few years, with age.



ned-ludd said:


> Also, regulator watches have three separate hands on three separate subdials. If you remove the 12-hour hand on this watch you wouldn't end up with a regulator because the 24-hour and minutes hands remain together on the one subdial.


Please don't get ruled by regulations: these change... May I beg to reset the time, at the risk of shaking some of your certainties? Originally, way before the IWC Portuguese Regulateur (btw inspired from a naval chronometer, not railroad régulateurs...) and the whole fad, this is what a true _Régulateur_ (implying _des Chemins de fer_) typically looked like originally. This one _professional tool_, not luxury watch:








Source: the forum of French railroad people, which btw seems to pack a wealth of traditions and lore
Forum cheminots - SNCF, ECR, VFLI, Europe, FRET - Photos et vidéos de trains - Usagers de la SNCF


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## ned-ludd

This Stührling Cuvette promised to be a simple conversion with its Ronda 515.24H movement but no...

















The 12-hour hand had a fairly hard steel grommet that popped out whilst reaming the 120 hole to fit the 160 24-hour pinion. Luckily the remaining hole was smaller than 160 so could still be reamed out and then the hand went on easily.
Putting the minute hand on wasn't quite so simple. For some reason the hand had a long 70 tube (~1mm) that made it sit fairly high, enough to foul the second hand and cause it to stutter at certain positions. After trying a few times to get it behaving I resorted to grinding the tube down (on a super-fine diamond lap) to a more manageable size of <0.5mm. The hand sits lower and clear of the second hand which now ticks freely. I have no idea how it worked originally. A bonus is that there's no longer such an obvious gap between the minute and the 24-hour hand.

Note the near-perfect alignment of the second hand. Sometimes you get lucky.

The light-coloured ostrich leather strap had to go as well. It just looked weird on my wrist.


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## paulhotte

That is quite a sort of hobby you've got there, hope to be posted on your progress...


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