Can VR3185 be modded to BB GMT? That would make CHS. Anyone tried this already?
Last edited:
-
Tired of adverts on RWI? - Subscribe by clicking HERE and PMing Trailboss for instructions and they will magically go away!
Black Bay GMT VR3185 movement?
- Thread starter Cadows
- Start date
QueTip would you be so kind to change the title to “Black Bay GMT VR3185 movement?”
- 13/10/16
- 3,917
- 2,394
- 113
Interesting question ... not easy to answer IMHO but really but really hallenging so I'll just share my thoughts here ...
Of course those are just MY thoughts so feel free to correct anything if I write any stupid crap ...
And sorry if my English is rough (not my mother tongue) ...
CASING THE MOVEMENT
Let's start with the movements dimensions
3185 :
diameter 28.5mm - thickness 6.65mm - T 2.65mm
2836 GMT :
diameter 26mm - thickness 5.6mm - T 2.75mm
Even if the BB case proves to be large enough to take a 28.5mm large movement and you manage to build a custom movement ring, you will have to deal with the 1.05mm difference in thickness.
There's a real risk that the rotor of the 3185 would touch the inside of the caseback, unless you thin the caseback from the inside to make place for the rotor to move freely.
Fortunately the stem heights seem to be be about the same ... 2.65 vs 2.75 is only 0.1mm
FITTING THE DIAL
Supposing you find a way to fit the 3185 movement in the BB case, you will have to cut the dial feets on the BB dial and and solder/glue new dial feets so that it fit the 3185
Not the most difficult thing to do and if you use glued dial feets that could modify the stem height from 2.65 to 2.75 ... which is good news
FITTING THE HANDSET - edited
Let's suppose you're there and you managed to case the 3185 movement in the BB case and to fit the BB dial on the VR movement ...
Then you will have to mod both BB hands and 3185 movement
Minute hand :
10.90 on 2836 and 1.00 on 3135 so you'll have to thin the canon pinion (which means partly dismantling the movement)
Second hand :
0.25 on 2836 and 0.18on 3135 so you'll have to tighten the hand tube
Hour hand :
1.50 on 2836 and 2.0 on 3135 so ?????
24 hour hand :
2.00 on 2836 and 1.40 on 3135 so ????
WHAT'S NEXT ?
Fitting the VR3185 stem on the BB crown sounds like peace-of-cake after all that work ...
FOREPLAY
First thing to do would be to measure :
- inside diameter of a BB case to check if it can take a 28.5mm movement + a custom movement ring
- clearance between the 2836 GMT rotor and the inside of the caseback
If those dimensions are OK or if you just have to remove a few parts of a mm fom the inside of the caseback then you could consider almost everything else doable ... with really steady hands and a really good experience in watchmaking.
Almost evrything else as you will have to deal with the Hour hand and 24 Hour hand tubes ... no idea at the moment ...
BTW ... I have a spare BB case and a 3135 movement (only 6.15mm thick) in my drawers so I'll check some dimensions as soon as I can.
Of course those are just MY thoughts so feel free to correct anything if I write any stupid crap ...
And sorry if my English is rough (not my mother tongue) ...
CASING THE MOVEMENT
Let's start with the movements dimensions
3185 :
diameter 28.5mm - thickness 6.65mm - T 2.65mm
2836 GMT :
diameter 26mm - thickness 5.6mm - T 2.75mm
Even if the BB case proves to be large enough to take a 28.5mm large movement and you manage to build a custom movement ring, you will have to deal with the 1.05mm difference in thickness.
There's a real risk that the rotor of the 3185 would touch the inside of the caseback, unless you thin the caseback from the inside to make place for the rotor to move freely.
Fortunately the stem heights seem to be be about the same ... 2.65 vs 2.75 is only 0.1mm
FITTING THE DIAL
Supposing you find a way to fit the 3185 movement in the BB case, you will have to cut the dial feets on the BB dial and and solder/glue new dial feets so that it fit the 3185
Not the most difficult thing to do and if you use glued dial feets that could modify the stem height from 2.65 to 2.75 ... which is good news
FITTING THE HANDSET - edited
Let's suppose you're there and you managed to case the 3185 movement in the BB case and to fit the BB dial on the VR movement ...
Then you will have to mod both BB hands and 3185 movement
Minute hand :
10.90 on 2836 and 1.00 on 3135 so you'll have to thin the canon pinion (which means partly dismantling the movement)
Second hand :
0.25 on 2836 and 0.18on 3135 so you'll have to tighten the hand tube
Hour hand :
1.50 on 2836 and 2.0 on 3135 so ?????
24 hour hand :
2.00 on 2836 and 1.40 on 3135 so ????
WHAT'S NEXT ?
Fitting the VR3185 stem on the BB crown sounds like peace-of-cake after all that work ...
FOREPLAY
First thing to do would be to measure :
- inside diameter of a BB case to check if it can take a 28.5mm movement + a custom movement ring
- clearance between the 2836 GMT rotor and the inside of the caseback
If those dimensions are OK or if you just have to remove a few parts of a mm fom the inside of the caseback then you could consider almost everything else doable ... with really steady hands and a really good experience in watchmaking.
Almost evrything else as you will have to deal with the Hour hand and 24 Hour hand tubes ... no idea at the moment ...
BTW ... I have a spare BB case and a 3135 movement (only 6.15mm thick) in my drawers so I'll check some dimensions as soon as I can.
Last edited:
- 13/10/16
- 3,917
- 2,394
- 113
Thanks ... not 100% certain of the dimensions as I know only those of the Gen 3085 but those of the clone should be close.
Apart from the fact that the modding a handset will be a real problem, I wonder if the work to be done is worthy just to go from ICHS to CHS.
I have already thighten hand tubes and thinned cannon pinions without any problem but I've never fitted a new tube on a hand.
Maybe KJ2020 can help a lot about the handset as he has already modded a handset from ICHS to CHS if I'm true.
Nevertheless I'll check all the dimensions I can and post it on that thread.
- 28/2/17
- 2,388
- 1,954
- 113
Are gen hands feasible? Would they have the right dimensions? Seems most of the problem lies in the hand sizes.
It always baffles me how much you guys know about this sort of stuff. I can only dream!
I wondered the same thing before, then I realized they have put years into this hobby and most of them learnt modding/watchmaking. Its good to have them here
Well if hands stack is all it takes to make this watch super rep then I think its worth to discuss right? Considering the price of the watch itself isnt so high I guess a lot of people would want CHS.
- 13/10/16
- 3,917
- 2,394
- 113
May I say that most of the problem lies in everything and not only yhe handset ... that mod, if it proves to be feasible, wouldn't be an easy one.
No idea about fitting Gen hands as I don't know which diameters are their tubes ... Tudor MT5652 is a manufacture caliber and I haven't found any specs about it aprat from it's diameter (31.8mm) and it's thickness (7.52mm).
About that thickness, which is huge, I think that if the Rep BB GMT case dimensions are close enough to those of the Gen, there would be a good chance that it will give enough clearance for the 3185 rotor to move freely, as the 3085 is 6.65mm thick only (0.85mm less than the MT5652).
But the Rep BB case is made for a 2836 GMT so nothing is certain.
I have checked the specs and pics of the BB GMT on PTs website and case is 41mm large and 15.5mm thick.
Below is a pic showing the 2836 GMT movement in the case
- red circle is 41mm (size of the case)
- green circle is 28.5mm (diameter of the 3185 movement if I'm true).
It seems that the case COULD be large enough to receive a 3185 clone movement with a custom movement ring
But there is no side pics showing how low or high the 2836 GMT rotor sits in the case and the caseback seems really flat.
Cadows as you opened that thread may I suppose that you already have a BB GMT ?
If YES what could be great is that you remove the caseback and check if the rotor of the 2836 GM sits high or low in the case and measure how deep is the caseback ... just to guess if there is clearance enough for the 1.05mm difference in total thickness between 2836 GMT and VR3185.
- 13/10/16
- 3,917
- 2,394
- 113
Thanks guys ... nothing that big here to be honest so anybody can do ...
All you need is a good calipder and curiosity ... plus you can check many informations about the movement on ranfft.de archive
So THINKING and GUESSING ABOUT a watch mod is quite easy as long as you spend enough time
DOING the mod is something other and I'm not certain I would try that one
despite the fact that I love challenges
- 13/10/16
- 3,917
- 2,394
- 113
Of course it's worth to discuss and even worth to try
Personnaly I don't really mind about CHS or ICHS but I'm picky about details that doesn't bother other watch fans ...
I'm just wondering how much such a mod would cost, if it proves to be feasable ...
- ZF BB GMT Pepsi : $318
- clone 3186 GMT movement : $160
- custom movement ring ; about $30
- modders work : I really have NO idea but that a would be a "first" and considering the modder will have to mod the dial, mod the hands, mod the canon pinion, etc ... that won't be cheap
I really don't think that such a project could be done for less than $900.
Which is far above the base watch price but, as you already said, that could make that watch a super rep