Making an 806 navitimer

[mnkoshka]

This is so cool, I was wondering how did you figure out the length for the pushers? That was the part that always stunted me was knowing how long of a pusher I would need. The St19 movements have awesome diagrams online which help make with dimensions for putting one in a watch but I was curious how the chrono pushers were working for you. Project is amazing and can’t wait to see it complete love the dial as well, gotta say that’s one of the cleanest 806 dials I’ve seen in a long time.


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I’m using 7750 navitimer pushers but they are about a 0.8mm too short. I’ll need to machine up some cap ends to press over the pusher shafts to increase the length. They currently push the movement leavers but a micron or two further would activate them LOL.


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[Raddave]

wow

 

[mnkoshka]

Some more photos of the case parts coming together. Chrono pushers, crown tube and bezel retainer with M1x0.25 threads tapped for retaining tabs. Installed the gen spec crystal to check for hands clearance. (Not fully pressed as this system requires crystal removal with compression tool to remove movement from the top side... the original is similar, bezel and crystal are removed but the original 806 design is flimsy and not water resistant). Blind lug holes are drilled also.

Unfortunately I had to seat the movement slightly lower in the case for the crow tube to avoid the bezels o-ring grooves. The slide rule may not sit exactly flush with the dial but slightly raised by about 0.2mm. The tolerances are so damn tight using the st-19. If I do another one of these in the future I’ll be using a Venus 178 to avoid the drama lol. Pics

 

[manodeoro]

mnkoshka your work is really amazing !!! and that watch will be soooo cool

May I ask how you managed to drill the blind lug holes and which tool you used to do this ?

 

[mnkoshka]

mnkoshka your work is really amazing !!! and that watch will be soooo cool

May I ask how you managed to drill the blind lug holes and which tool you used to do this ?

It’s actually harder than I thought to do accurately. some watch companies use a CNC machine especially built and dedicated to do perfect X axis drilled blind holes. This machine can drill lugs for straps as small as a 12mm wide. others simply use a long series centre style drill and drill on a 5-8 degree offset depending on lug shape, so basically how I did it. Using an angular vice on a mill drill on an angle over the top of the opposite lug at around 8 degrees from the vertical Z axis. This procedure can be risky and loss of accuracy can occur due to the very small drill deflecting off the angular surface. Managed to do it okay but could be off a few micron haha, I need better drills for this.


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[trailboss99]

Wow! Amazing work mate, I bow to your vastly superior machining skills, I'd make a hash of that for sure.

 

[DrHack]

Fantastic work, I am very impressed. This will be a beautiful watch! Subscribed.

 

[Clarkent]

WONDERFUL!


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[deadpan]

Stunning work.

 

[GDTrep2001]

Oh man, just saw the st1902 diagram and MAN that stem is highhhhhh. Idk how you got this to look so smooth without the stem rubbing into the bezel but gosh that is one incredible looking watch


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[mnkoshka]

Challenge after challenge with this project but finally got it together, I’m just waiting on the slide rule print. I machined a slide rule so once the filmless decal transfer is printed I’ll install it and finished. Haven’t pressure tested it yet but I washed it and all was fine lol. Had to also machine little brass sleeves to extend the chrono pushers.

had to redesign the bezel retainer and instead of using movement tabs to hold it in i machined a C-clip with holes and a hook to clamp the retainer into the case and the hook sits in a notch in the case to keep everything from rotating and lock everything except the bezel. Couple more photos. Hopefully have final pics up soon and may make an alloy bronze version of this as well if I get time... I will also make my own transfer guilt dial to go with it.
pics

 

[kilowattore]

Challenge after challenge with this project but finally got it together, I’m just waiting on the slide rule print. I machined a slide rule so once the filmless decal transfer is printed I’ll install it and finished. Haven’t pressure tested it yet but I washed it and all was fine lol. Had to also machine little brass sleeves to extend the chrono pushers.

had to redesign the bezel retainer and instead of using movement tabs to hold it in i machined a C-clip with holes and a hook to clamp the retainer into the case and the hook sits in a notch in the case to keep everything from rotating and lock everything except the bezel. Couple more photos. Hopefully have final pics up soon and may make an alloy bronze version of this as well if I get time... I will also make my own transfer guilt dial to go with it.
pics

Hey, if you make another one I call dibs

 

[mnkoshka]

Hey, if you make another one I call dibs

if I make another I’ll try make a couple whilst I’m Tooled up. Could be a while away though. But will definitely keep you in the loop


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[GDTrep2001]

Just a question but I was wondering what is the space between the parts to make the bezel rotate? For something that small is it .25 mill gap or is it even less?


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[GDTrep2001]

Mil* as in mm my bad, long day at work has my spelling all over the place????


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[mnkoshka]

Just a question but I was wondering what is the space between the parts to make the bezel rotate? For something that small is it .25 mill gap or is it even less?


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The bezel fits to the case with about 0.040 clearance it had to be close as there’s a very small lip holding the bezel inline with the case. The bezel also relies on o-ring in its groove 0.3mm depth in the case and 0.3mm in the bezel. The o-ring is 0.8mm thick and when compressed The downward force on the o-ring has to be tensioned right by the C- retainer so that the metal surfaces only very very slightly come into contact this stops the bezel from jamming but still have enough force to rely on the o-ring for waterproofing and smooth rotation. So basically the bezel is aligned in the case by a lip and floats on a well lubricated o-ring.


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[mnkoshka]

Transfer print on the slide rule went okay but will try a better one once I airbrush a white blank. Hoping to source an original eventually.

 

[gunsmoke16610]

Transfer print on the slide rule went okay but will try a better one once I airbrush a white blank. Hoping to source an original eventually.

Fantastic end result, I really enjoyed this thread. Your skills are among the best!

 

[mnkoshka]

Fantastic end result, I really enjoyed this thread. Your skills are among the best!

Thanks very much mate really hoping to make more of these some day but maybe with a sellita SW510 . Would love to create a transfer decal dial of my own for the twin Register I’m sure there’s a few guys here than can help create artwork to print filmless decals.

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[mnkoshka]

Just a another fun project to add to this thread.
I had a montbrilliant triple date dial and handset. Thought I’d make another vintage case set using a valjoux 7751, this one is 42mm... it was a little easier tolerance wise for the crown hight and obstruction to bezel design. Always wanted a vintage tripe date with rice bead bezel, Had to make a slide rule from scratch as well which came out okay.







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