RWG Technical Posted October 14, 2011 Report Share Posted October 14, 2011 Many want to install genuine crowns on various PAM models. When it comes to handwind models, most of the genuine crowns are designed for automatic's, and therefore the stems are sized at 0.90mm. The problem is that handwind 6497 stems are only available in 1.20mm size. So why not re-thread the 1.20mm stem down to 0.90mm? Short answer is that it can't be done, the stems are so hardened that they can't even be cut with a carbide graver. If you can't cut it with a carbide graver you have no chance to re-thread it to 0.90mm with a HSS die. Why not simply use a stem adapter from 1.20-0.90mm? Can't be done. Handwind movements are very large and the thickness of the case is very small, so small that the genuine crown touches the movement when it's installed. You don't have enough thickness to install the stem adapter as it takes up too much room. The only solution is to fabricate a complete stem from scratch. Here I fabricate a new stem from high carbon steel, these are some of the steps required to accomplish that task... Up first, a picture of the genuine crown and the original 1.20mm stem. I am using a high carbon steel rod of 2.50mm, here you can see the original stem next to the bar stock. I take 1.10mm off the rod and turn it down to 1.40mm diameter, the overall diameter of the original stem. Here is the comparison of the original stem next to the rod. The first part that needs to be cut is the tip, here is the start of that operation. All done the tip. Genuine on the right, rod on the left. Next I have to fabricate the square section of the stem, this is the part that the clutch wheel rides on and allows handsetting and winding. All 4 sides have been cut down, the overall dimension is within 0.01mm of the required 0.90mm dimension accross the flats. I check my work by test fitting the clutch wheel. Next up I have to make the notch for the set lever pin, this is the pin that holds the stem in place and allows switching from timesetting to winding. Notch has been fully cut to the required depth. Next the stem is removed and flipped over. I trim it down to be able to thread it to 0.90mm and start the treading process. Overall view after full threads cut. And here you can see the results of my labour, a hand made custom stem, fitted for a 6497 with a 0.90mm thread, it is test fitted into the genuine crown, all that remains is to trim the stem to length so the crown fits up nicely against the case. Overall the process takes over an hour to complete. As you can probably appreciate, it takes a lot of skill to be able to make such a small part to such exact dimensions, and actually have it work and fit the genuine movement clutch and crown gears. Definetely not for the faint of heart or wannabe watchmakers... Thanks for reading. 2 Quote Link to comment Share on other sites More sharing options...
redwatch Posted October 14, 2011 Report Share Posted October 14, 2011 That is just awesome Ziggy!! Thanks for taking the time to snap pics during each step of the process!! What kind of lathe are you using for this? Quote Link to comment Share on other sites More sharing options...
vlydog Posted October 14, 2011 Report Share Posted October 14, 2011 I have so much respect for the skill and craftsmanship that goes into a job like this. Thanks R for detailing it with such precision in your photos. The Zigmeister had to perform this very feat when he installed my Gen auto crown on my manual wind PAM. I am so much more appreciative after seeing this post. Bravo R! Quote Link to comment Share on other sites More sharing options...
dluddy Posted October 14, 2011 Report Share Posted October 14, 2011 Quote Link to comment Share on other sites More sharing options...
Watchmeister Posted October 14, 2011 Report Share Posted October 14, 2011 Holy cow! Great stuff. Impressive work and equally impressive post. A custom stem for a pre-v project...somewhat fitting. Quote Link to comment Share on other sites More sharing options...
krpster Posted October 14, 2011 Report Share Posted October 14, 2011 Truely amazing work! We are not worthy. Quote Link to comment Share on other sites More sharing options...
Ronin Posted October 14, 2011 Report Share Posted October 14, 2011 Genius!!!! Quote Link to comment Share on other sites More sharing options...
freddy333 Posted October 14, 2011 Report Share Posted October 14, 2011 Not many watchmakers around today who can execute that level/quality of lathe work. You are truly a Master, Ziggy. Quote Link to comment Share on other sites More sharing options...
dbutlerman Posted October 14, 2011 Report Share Posted October 14, 2011 That is really impressive. I'd like to be able to make my own stems. That'd save me a lot of waiting on stems to arrive from the supply houses. Quote Link to comment Share on other sites More sharing options...
PeteM Posted October 14, 2011 Report Share Posted October 14, 2011 Fantastic work mate Thanks for sharing and Thanks for being here for us.... This hobby wouldnt be half as good without you Quote Link to comment Share on other sites More sharing options...
Utheman Posted October 14, 2011 Report Share Posted October 14, 2011 I know I'd never be able to do anything like that, but it's nice to know how it's done. Thanks for sharing. Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted October 14, 2011 Author Report Share Posted October 14, 2011 Thanks for the feedback everyone. I wasn't sure if there was any interest in these types of posts anymore, seems as if there is so that's good. @PeteM, look closely, you will be seeing this particular stem and the other I made for your case sets...they are yours. Next up will be the case tube fabrication, stay tuned. @redwatch, all work is completed on a watchmaker 8mm lathe. @db2, Quote Link to comment Share on other sites More sharing options...
redwatch Posted October 14, 2011 Report Share Posted October 14, 2011 @redwatch, all work is completed on a watchmaker 8mm lathe. Thanks R. Out of curiosity, how on earth did you do the squared off portion for the clutch wheel? I assume that wasn't done on the lathe as it would have been spinning? Do you have a mill attachment for yours as well? Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted October 14, 2011 Author Report Share Posted October 14, 2011 Thanks R. Out of curiosity, how on earth did you do the squared off portion for the clutch wheel? I assume that wasn't done on the lathe as it would have been spinning? Do you have a mill attachment for yours as well? I do have a milling attachment, but I don't use it for this procedure. The squared section is done with a file and then a arkansas stone using a roller rest as a guide. It has to be done carefully and exactly, or it simply won't work... Quote Link to comment Share on other sites More sharing options...
maxman Posted October 14, 2011 Report Share Posted October 14, 2011 Genius!!!! Im with Ronin...absolute "Genius" Thank you so much for sharing your skill/expertise and time with us Zigmeister. :thumbs: Mike Quote Link to comment Share on other sites More sharing options...
krpster Posted October 14, 2011 Report Share Posted October 14, 2011 I do have a milling attachment, but I don't use it for this procedure. The squared section is done with a file and then a arkansas stone using a roller rest as a guide. It has to be done carefully and exactly, or it simply won't work... Wow! Just Wow. I would love to just sit in the corner and watch some of these procedures take place. Quote Link to comment Share on other sites More sharing options...
specialvat Posted October 14, 2011 Report Share Posted October 14, 2011 These are my favorite types of post, thanks for taking the time to show us all. Amazing stuff Quote Link to comment Share on other sites More sharing options...
ubiquitous Posted October 14, 2011 Report Share Posted October 14, 2011 Unreal! Quote Link to comment Share on other sites More sharing options...
PeteM Posted October 14, 2011 Report Share Posted October 14, 2011 Thanks for the feedback everyone. I wasn't sure if there was any interest in these types of posts anymore, seems as if there is so that's good. @PeteM, look closely, you will be seeing this particular stem and the other I made for your case sets...they are yours. Next up will be the case tube fabrication, stay tuned. Yes mate always loads of interest and admiration I knew that was mine mate as I had written my name between the threads... which I was just able to make out from your pics ;) Fantastic work R as always mate.... got me all excited Quote Link to comment Share on other sites More sharing options...
gianton Posted October 14, 2011 Report Share Posted October 14, 2011 Very good work! 1 Quote Link to comment Share on other sites More sharing options...
Rolexman Posted October 14, 2011 Report Share Posted October 14, 2011 Amazing!!! You deserve the name meister. Unbelievable skills man! Thanks for the write up. Mark Quote Link to comment Share on other sites More sharing options...
valerian Posted October 15, 2011 Report Share Posted October 15, 2011 Once again, thanks for showing. Very impressing. Val. Quote Link to comment Share on other sites More sharing options...
coolfire Posted October 16, 2011 Report Share Posted October 16, 2011 Awesome, as always! Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted October 16, 2011 Report Share Posted October 16, 2011 Love it!! I've done some turning of wood spindles on big wood lathes. Can't even thinking about dealing with miniscule watch parts on a lathe though! Quote Link to comment Share on other sites More sharing options...
w0lf Posted October 19, 2011 Report Share Posted October 19, 2011 Awesome! Thanks for posting this Quote Link to comment Share on other sites More sharing options...
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