RWG Technical Posted October 14, 2011 Report Share Posted October 14, 2011 If you are going to install a genuine crown onto a PAM case, you need a matching tube. I have seen a number of genuine crown installs where the original tube was retained and simply drilled out larger to fit the gen crown pipe, that is not a good solution, in fact it's a horrible solution. Why? well simply because the rep tubes typically have an o'ring on them and the o'ring is inserted into a notch cut out of the inner edge of the tube, the notch in the tube for the o'ring damages the o'rings on the gen crown, the damage means that the seal is non existant and the case is allowed to breath with long term damage to the movement. Also, the majority of the rep tubes do not fit correctly against the vertical crown o'ring which provides the seal when the CG lever is closed. Basically by installing a gen crown in a rep tube, you end up with a case that is open to the atmosphere and that is sucking in dirt and moisture everytime the watch is worn, eventually the watch will be ruined. The correct way to install a genuine crown is to fabricate a matching tube, a tube that fits the case properly, and more importantly, fits and makes full use of the 3 crown o'rings (2 on the pipe and 1 on the crown) and provides the required seal. First part of the work is to drill the hole in bar stock, the hole is for the crown to fit into, the drilling is done in stages from small drill to large drill... Next up, I cut the tube down so that it will fit into the case. This is done carefully and the final dimension is to have a slight taper to the finish so that the tube can be press fitted tightly to the case. Once that is finished, I have to cut the tube away from the bar stock so I can fit and finish it. The tube is flipped over and re-installed in the lathe. The crown is test fitted, the pipe fits the tube correctly but if you look closely the tube is too large in diameter and doesn't seat properly against the 3rd o'ring in the crown. So I reduce the diameter of the outside of the tube until it just fits into the crown, you can see the slight gap between the crown and tube, a perfect fit, a fit that will provide the correct seal once the CG lever is closed. Next the tube gets a polish. The tube is ready to be press fitted into the case. And a quick look at the inside shows that it's the correct length and fully seated. With the crown installed, the crown o'ring is touching the new tube and there is just enough of a gap between the crown and the case to allow the CG lever to press the crown home and flush against the case and seal it all up. When done correctly not only is the crown supported laterally so you don't get a wobble, the pipe o'rings provide a constant seal, and the crown ring does the final sealing when the CG lever is closed. All in all a professional installation. Total time for fabrication of the tube is just under an hour. Thanks for reading. Quote Link to comment Share on other sites More sharing options...
krpster Posted October 14, 2011 Report Share Posted October 14, 2011 Awesome! Keep them coming For me seeing this kind of thing is what this is all about. Also, your time to manufacture is equally as impressive as the result. Wish I could learn to do it Need an apprentice? As a side question do you think you can make a new pusher stem? I have a piece that needs some help Actually never mind I know you can. Quote Link to comment Share on other sites More sharing options...
fijikid Posted October 14, 2011 Report Share Posted October 14, 2011 Thanks for that post! Just incredible stuff! Any interest in a 40 year old intern that can cook really well? Can I bring my wife and kid too? Quote Link to comment Share on other sites More sharing options...
PeteM Posted October 14, 2011 Report Share Posted October 14, 2011 Great mate.... a really useful thread and something I never truly appreciated in terms of the potential damage especially to the movement.. You mention the rep tube has a gasket on the inner edge, typically.... but what about a gen tube? For example if you have a more recent gen PAM case (say 6 years old) with a tube to recieve the single gasket gen crown (Pre Hex type) then can you mod this to recieve the double gasket crown or does it need a new bespoke fitted tube... to prevent the isues you raise in your post.. Thanks again mate ... Quote Link to comment Share on other sites More sharing options...
redwatch Posted October 14, 2011 Report Share Posted October 14, 2011 Yet again another awesome post Ziggy! Thanks for that! Quote Link to comment Share on other sites More sharing options...
jmb Posted October 15, 2011 Report Share Posted October 15, 2011 Super! One of these days maybe I'll get a small lathe... Quote Link to comment Share on other sites More sharing options...
hackR Posted October 15, 2011 Report Share Posted October 15, 2011 love reading these...awesome!... Quote Link to comment Share on other sites More sharing options...
gianton Posted October 15, 2011 Report Share Posted October 15, 2011 You're the master! Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted October 15, 2011 Author Report Share Posted October 15, 2011 Thanks for the positive feedback everyone. @krpster, should not be a problem to make a pusher, as long as I have the old one as a guide or exact dimensions...let me know if you are interested. @PeteM, the rule of thumb would be, if the gen crown has o'rings on it's stem pipe (like yours does), then you need a smooth bore case tube to allow the o'rings to seat and do the sealing. If the stem pipe is smooth, then you need a tube with an o'ring in it, to provide the seal. I would love to have an apprentice, it's just too bad we all live so far apart... Quote Link to comment Share on other sites More sharing options...
dluddy Posted October 15, 2011 Report Share Posted October 15, 2011 Unbelievably cool Zig Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
dvn Posted October 15, 2011 Report Share Posted October 15, 2011 Amazing master Zig. Is there anything that you can't do? Quote Link to comment Share on other sites More sharing options...
valerian Posted October 15, 2011 Report Share Posted October 15, 2011 I absolutely love those step-by-step tutorials, even though I lack the skills and the tools necessary to perform anything like this. It's just a thing of beauty how something so neat and clean is developed. Thanks so much for showing this! Keep up your great work, Zig! Kind regards Valerian Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted October 15, 2011 Report Share Posted October 15, 2011 Great stuff. The correct tube for a pre-v crown. Quote Link to comment Share on other sites More sharing options...
pizzanooo Posted October 15, 2011 Report Share Posted October 15, 2011 A never ending source of education, thanks Zig. Keep em coming! Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted October 16, 2011 Report Share Posted October 16, 2011 Fantastic work. I wouldn't have thought you were starting with bar stock! Quote Link to comment Share on other sites More sharing options...
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