BP SD with generic Xtal

[ado213]

I have not been happy with the chamfer shape and height of the BP Xtal for some time. A recent post on RWG got me thinking about this and I decided to see if it was possible to fit a generic xtal to the BP. I don't have access to a genuine Xtal but I am told both WSO and ST xtals are the same size as gen and do actually fit the gen SD.

So off I go, firstly the BP case is bored to accept a 30.1 mm Xtal and the gen Xtal and gasket are 29.6 so we immediately have a problem. Secondly the genuine SD has a three part Xtal assembly comprising of Gasket, Rehaut and Xtal. The BP has a two part assembly with no separate rehaut.

So were f----d?, well here's how I got round it.

Firstly bore the case 30.1 x 3mm deep



lets tackle the diameter differences between BP and generic Xtal first, so we will have to make a spacer tube (sleeve) that makes up the difference between 30.1 (BP case bore) and the 29.6mm were going to fit, you will see this to the right of the case shot, but here is a better picture



Ok that done lets make the separate rehaut, just like this one



Not happy with the finish on this one, but next time I will use a better tool to get a better finish. So we have the "sdlleve" the rehaut, now lets see if the sub assemble?. Sleeve in case



Then. rehaut, Xtal and gasket



Looks Ok, but how's the fit?, well it feels good at the moment so lets get them all in the case ready to press home



Great, its nice and tight to press in but not too tight, it gives me a bit of confidence this will be good on WR. So here we are after pressing with a top view of the case assembled



And a comparison of the stock BP on the right and the gen Xtal just fitted on the left you will notice the height difference which is what I was looking for. As I haven't got a gen to measure I'm only going of photographs of a gen kindly sent to me by Ticktick over on RWG.



So in conclusion it is possible to fit a gen Xtal to a BP SD. hope you enjoy!!

 

[Rudy40]

Wow great work!
The first member here that tried to install a gen crystal was surf..that I know of ?
He reported to me that it would have to be epoxied in!
I never tried...I have gave up! But this breaths new air into the SD build that I'm getting ready to build!
What tools are needed to perform this task? Very interested?

 

[Raddave]

Nice work !!!!

 

[P4GTR]

Awesome work A.

 

[justlounging]

Wow! Interesting and kudos on this attempt!

Now to test the WR and you'll know if the tolerences are spot-on

 

[IWC Doppelchronograph]

Ado please post a better picture if the height differences , many thanks

 

[ado213]

Generic Xtal in BP SD

Hi Adey, as requested better pictures of the stock BP SD and the modded BP SD. I'm not the best at photography, but hope these show the difference better?.

First of all the stock BP



Now the modded BP SD



Now both side by side



And an edited (lightened) earlier photo of them both side by side



And now one of the completed watch showing the separate rehaut, the angle I took this photo at makes the indices markers look closer at toward the 12 O'clock area, this is not the case the indices are very evenly spaced. In fact they look very gen like, just not touching the rehaut.



The reason I wanted to crack this is because there seems to be an absence of replacement BP Xtals, can get one at all. So in the future this post may be of use to other members. Also I liked the idea of being able to fit genuine in this particular rep, it deserves it!.

Back to the technical stuff. I measured my stock BP from the top of the Xtal down to the insert (neither have been flattened on the back) this measured 1.86 mm

From the same datum on the modified SD it measured 1.43mm, making the difference in height between the two 0.43mm,
quite significant I think.

Don't forget, I am purely guessing at the height I need to be at, the absence of a gen SD for measurements relies on my eye rather than a vernier. Good thing is, if I need to come up a little to match gen I can, I can also go down a further 0.2 mm if needed.

On WR, I have tested this to 6bar, bubble free. As the crystal now sits deeper in the case I am confident this will pass at 10 bar. This will be my next test, just waiting for my 10bar upgrade to go on my Bergeon (any day)

Hope this is of interest, any questions fire away!!

 

[ado213]

Oh, almost forgot, for the techy's, sectional drawing of Genuine SD

 

[IWC Doppelchronograph]

Great, fantastic insight thanks Ado

 

[moodyticker]

Insightful work yet again Ade, hats off!

 

[ianm]

Really nice work, very skillful.

 

[Rudy40]

Rep points given...Awesome feet! Congrats

 

[Q5?]

Awesome! Rep points to you!

 

[Thrasher]

Fantastic

 

[Rudy40]

I'm going to bump this because it took a lot of trail and error to be able to make this work! My hats off to you mate!
This is a much needed mod to the BPSD!


Sent from my Rolex thinking brain!

 

[Thrasher]

I will give it another bump as this is a great mod for serious Sea Dweller builders.

 

[Maron]

[MENTION=114500]wollerau[/MENTION]

and bump

 

[Thrasher]

This is probably the best project I have been involved with so far!

 

[Thrasher]

Adrian @ado213 completed this whole project with his crystal Mod and case shaping. TC parts and a new swiss eta H4 that he serviced for power. It has a WSO gen Spec crystal, WSO tube, Gen crown, Gen Insert, TC Dial and hands, TC Bracelet, TC DWO V4. The bracelet is soaking in baby oil right now and in the future Adrian maybe able to work some genuine magic on the the bezel at that time I may have him replace the hands with TC V2 hands.

I will get better pictures soon.

I asked that the crystal be on the low side of genuine.

Thank You Adrian!

 

[alessandri]

[MENTION=82129]Thrasher[/MENTION] looks awesome!


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