How to make a better cannon pinion for a Panerai 7750 movement.

[sander]

As we already discussed in milesd topic and as Sul said, we don't want to spoil his wonderful topic of his new watch, so I decided to write a new one.

For me one of the biggest tells with a 7750 in a panerai, is the high cannon pinion. The problem is caused by the hole in the pinion which is normally needed for the chrono hand. To close the hole, they made a nickel plated brass cap which sits on top of the pinion.

If you take off the cap, the pinion is the right height but then you will end up with a hole in the middle. If you sand the cap down, you will notice that you can't sand it enough (because no cap at all is the right height )

and it will also turns yellow because you remove the nickel. To solve this problem, I have modded the pinion with a new stainless steel cap.

First I removed the standard cap and cut off the piece that normally holds the hand.Then I made a new cap out of a stainless steel rod. (it was actually a 1,26 mm nail )

I made it a tight fit so that the cap is pressed in place. (see drawing)

You also have to cut a little piece of the brass rod of the main plate. Because the cap sits lower, you cannot install the pinion correctly over the brass rod. It's not a problem to cut it down a little because this rod holds the jewel for the chrono seconds hand, which is not needed in this case. If you cut off just a little there is enough rod left to support the pinion.

It's a pretty tough mod because of the size it's difficult to work on.

Another issue is that you will have to completely service the movement because you have to cut a piece off from the brass rod of the main plate.

Since I don't believe it's possible to do this without getting filings into your movement it's better to give it a service as well.

Actually, a service is always welcome

Cheers!

Sander

[nakortheblue]

As usual, sander, your mods are amazing!

[sander]

As usual, sander, your mods are amazing!

Thanks mate

[z3k0]

So, you didn't have to cut the pinion itself, just replace one cap with another - did I get this right ?

Fantastic work BTW, it is bothering me for long time, but making new cap is currently beyond my capabilities

If you happen to make extra cap or two, and decide to sell them, let me know

regards

[sander]

So, you didn't have to cut the pinion itself, just replace one cap with another - did I get this right ?

Fantastic work BTW, it is bothering me for long time, but making new cap is currently beyond my capabilities

If you happen to make extra cap or two, and decide to sell them, let me know

regards

No you do have to cut the pinion as well. (look at the drawing)

you cut it down till the dotted line.

[FxrAndy]

great work mate

[Lobster]

When it comes to things that most feel is impossible to do, you seem to find a solution.

great stuff

[txcollector]

Life saver!!! I had this mod in my cross hairs but not idea where to start. That will save me a LOT of work. Thanks a lot for sharing.

[sander]

THX guys!

[RWG Technical]

Well done, I have done a number of these as well, it's a very difficult machining job for sure, especially handling such a small piece. But then if it was easy, anyone could do it...

Great pictures, very informative, you are very skilled.

[FxrAndy]

you know what i made a vintage pearl the other day and that did not have to be that precise and it was still a pita, but mackinging SS that fine, well done

[txcollector]

question: could you protect the plate with a wrapping plastic to avoid having to service the movement? I usually wrap things to avoid dirt and shavings to hit any movement parts when I'm working them.

and yes, I'm lazy. Servicing a 7750 is NOT fun.

[sul]

Good work sander

[sander]

Thanks for all the comments.

Since my wife really don't understand what the fun is creating a piece which is almost too small to see, I really appreciate it that you guy's do!

I received some questions how I actually cut the cap.

Here you go:

First I put the nail (1.26mm thick) in the Dremel and used a needle file covered with fine (800 and 1200) sandpaper to shape it down to 1.20mm

Then I put the 1.20mm part of the nail into the Dremel and shaped the other end down to 0.70mm

Now you have a nail (total length about 0.50 cm.) which is 1.2mm on one half and 0.70mm on the other half.

The next thing was to shorten the 0.70mm side down to 0.40mm. After that I installed it into the cannon pin.

Now I had a cannon pin with a very tall cap. The next step was to cut down the cap to the proper length and polish it.

I made some drawings to clarify it.

[hooky]

Thanks. Don't have the skills and tools for this, but my local watch smith does. Will use it on my fully modded pam252 and 156 later. Thanks so much.

Have to say, once in a while a very rare and quality wise good informative modding thread is started. This is one of them.

[sander]

Thanks. Don't have the skills and tools for this, but my local watch smith does. Will use it on my fully modded pam252 and 156 later. Thanks so much.

Have to say, once in a while a very rare and quality wise good informative modding thread is started. This is one of them.

bedankt maat maar nu naar bed!

[redwatch]

Ok, first of all, coming up with the mod itself was just pure genius! I don't own a 7750 powered PAM, nor will I at anytime. However, as an engineer & tinkerer, I can definitely appreciate the ingenuity put forth in coming up with this mod. I applaud your skills Sander!

Secondly, to take the time to do such an incredibly detailed outline of exactly how you did it, including graphical references, is just awe inspiring! A huge kudos to you!!

[Ronin]

It is members and great technical work arounds like this that make RWG "The Best" Rep/Watch forum on the planet! Great job!

[Migge]

Amazing work once again Sander,

you are very skilled and your modifications never stops amazing me

[krpster]

Great job Sander. My only question regarding the detailed step by step you gave (thanks for that by the way) is in the final step. What method did you use cut down the tall cap once attached to the cannon? I assume something with the dremmel again.

Amazing work!

[StormTooper4]

Stunning post , thank you for taking the time to put it together

[sander]

Great job Sander. My only question regarding the detailed step by step you gave (thanks for that by the way) is in the final step. What method did you use cut down the tall cap once attached to the cannon? I assume something with the dremmel again.

Amazing work!

Started with the Dremel

After that the needle file

After that the needle file covered with 800 sandpaper

After that the needle file covered with 1200 sandpaper

Finally polishing on the buffing machine.

[mas6002mi]

holy cow! wish i had these skills....and the tools.

[ocram]

This post and the work behind is a

Amazing!!!

You should start building some caps and sell them here.

I'd be in for three!!! :-)

[btocamelo]

awesome work! I would buy one as well!