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The Water Cooler
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Watch Rebuild – OSA Member Owned – U.S. Contract Pilot's Watch Issued In Vietnam – LONG POST - PIC HEAVY
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<blockquote data-quote="thor447" data-source="post: 3906920" data-attributes="member: 24867"><p>Assembly went really well. I'm sorry for the lack of photos for this part, but once I get going putting one of these back together I just get hyper-focused on what I'm doing and taking photos slips my mind.</p><p>I did take 1 single photo during the assembly process however! After cleaning, the very first step I do when assembling the watch is to put the mainspring, barrel, and arbor back together. With the initial low amplitude ratings we were seeing, and the age of the watch, I was somewhat anticipating needing to replace the mainspring. During disassembly I found that this watch had the mainspring replaced already, no doubt from the watchmaker in 1997. The mainspring in this watch was of a newer type than what would've come originally in this watch. Once removed from the barrel it had no kinks in it, and sat level, which is what you want to see. After disassembly I told the owner of the watch that I'd like to try re-using the existing mainspring first to see what kind of numbers we can get out of it. These newer types have a much better temper in them, and will last decades longer if properly serviced. When I first took the barrel apart during disassembly I found that it had about 5x too much grease in it, which had gummed up.</p><p>Here's the pic of the mainspring and arbor cleaned, lubricated, and re-installed into the barrel (before I installed the top piece of the barrel). It gives you a great view of how a non-automatic mainspring sits in a step on the inside of the barrel wall. When you wind a manual watch, when you reach full wind you feel resistance when trying to turn the crown. This resistance comes from the barrel being at full wind (spring moves inward toward the arbor), and the catch you see the spring sitting in on the inside edge of the barrel engages and prevents you from going further. This is why they tell you to NEVER over-wind or muscle through when winding a manual watch. This is a breaking point if you put too much force on it.</p><p></p><p>[ATTACH=full]322745[/ATTACH]</p><p></p><p>The other issue I found is that the barrel had too much side shake when the bridge is mounted (no pics). This will happen over time because the pivot on the barrel arbor will wear out the bearing walls of the bridge when it rotates. Along with the dirty jewels, and gummed up mainspring, this was absolutely contributing to the poor amplitude numbers we saw during the initial testing. I used a staking set on the bridge and closed that arbor pivot point, and then used a smoothing broach to open it back up to the correct diameter, it also burnishes the inside walls of that bearing race to make it less resistant to wear in the future.</p><p></p><p>After the initial assembly was complete, it put a full wind in it, let it run for about an hour, and then put it on the timegrapher for initial regulation. After about 10 minutes of adjustments, here's where you find out if all the work being put in to the watch was worth it.</p><p></p><p>[ATTACH=full]322746[/ATTACH]</p><p></p><p>As you can see, it's running SO much better. I got it down to 0 to 3 seconds per day in the dial up position, amplitude is excellent at 278 degrees (which tells me that we don't need a replacement mainspring), and the beat error I got down 0.0 – 0.1.</p><p></p><p>I couldn't have asked for better results, but this isn't the end of the work needing to be done to a watch movement after it's serviced. The watch needs to be put on a full wind and ran in for at least 24 hours. This allows the lubricants to settle in the jewels/pivots, for the barrel to unwind and distribute the lubricant, etc.</p><p></p><p>I finished the assembly in the evening, put it on the timegrapher, and left it alone for 26 hours. The s/d reading will always change after it's initial run-in, and the amplitude will drop as the mainspring unwinds over that 24 hour period. The rule of thumb for this type of manual movement is that you want to see amplitude drop to no less than 210 degrees (general rule of 190 degrees on automatics – not counting Japanese movements which are designed to run on lower amplitudes). Although I didn't get a picture of the initial readouts after 24 hours, the s/d had dropped (as expected) to about 9 s/d in dial up, and had been holding steady at that level for quite some time. The amplitude had only dropped to 255, which is fantastic.</p><p></p><p>Now that the movement had been run in, I did a full regulation (in multiple positions). Here's a photo of the same dial up position after everything was said and done, and the watch had been fully reassembled back into the case.</p><p></p><p>[ATTACH=full]322747[/ATTACH]</p><p></p><p>I think you've seen enough of these timegrapher readouts to know what looks good and what doesn't. I'll let you be the judge! I'll just say that my hat is off to these old Benrus movements. The readout in the dial down position is very close. Crown left, right, etc. positions saw a drop in amplitude, but everything was working great. FYI – a drop in amplitude from dial up/down to any other position will happen because the watch is on it's side. All of the points of friction on the balance, wheels train, etc. are no longer on the tips of the pivots, but now on the side of the pivots which have a much larger surface area. This creates more friction, which equates to lower amplitude. Even the best watches in the world see this same drop. This why to properly regulate a watch, you have to test it in multiple positions. Dial Up, Dial Down, and Crown Down (position when standing with your arm hanging) are the 3 most used positions a watch well ever be in. The smaller you can make that variance between those positions, the more accurate the watch will keep time while going through the motions of being worn throughout the day.</p><p></p><p>Continued on next post.</p></blockquote><p></p>
[QUOTE="thor447, post: 3906920, member: 24867"] Assembly went really well. I'm sorry for the lack of photos for this part, but once I get going putting one of these back together I just get hyper-focused on what I'm doing and taking photos slips my mind. I did take 1 single photo during the assembly process however! After cleaning, the very first step I do when assembling the watch is to put the mainspring, barrel, and arbor back together. With the initial low amplitude ratings we were seeing, and the age of the watch, I was somewhat anticipating needing to replace the mainspring. During disassembly I found that this watch had the mainspring replaced already, no doubt from the watchmaker in 1997. The mainspring in this watch was of a newer type than what would've come originally in this watch. Once removed from the barrel it had no kinks in it, and sat level, which is what you want to see. After disassembly I told the owner of the watch that I'd like to try re-using the existing mainspring first to see what kind of numbers we can get out of it. These newer types have a much better temper in them, and will last decades longer if properly serviced. When I first took the barrel apart during disassembly I found that it had about 5x too much grease in it, which had gummed up. Here's the pic of the mainspring and arbor cleaned, lubricated, and re-installed into the barrel (before I installed the top piece of the barrel). It gives you a great view of how a non-automatic mainspring sits in a step on the inside of the barrel wall. When you wind a manual watch, when you reach full wind you feel resistance when trying to turn the crown. This resistance comes from the barrel being at full wind (spring moves inward toward the arbor), and the catch you see the spring sitting in on the inside edge of the barrel engages and prevents you from going further. This is why they tell you to NEVER over-wind or muscle through when winding a manual watch. This is a breaking point if you put too much force on it. [ATTACH type="full" alt="15 - Mainspring - Cleaned Lubricated & Reassembled.JPG"]322745[/ATTACH] The other issue I found is that the barrel had too much side shake when the bridge is mounted (no pics). This will happen over time because the pivot on the barrel arbor will wear out the bearing walls of the bridge when it rotates. Along with the dirty jewels, and gummed up mainspring, this was absolutely contributing to the poor amplitude numbers we saw during the initial testing. I used a staking set on the bridge and closed that arbor pivot point, and then used a smoothing broach to open it back up to the correct diameter, it also burnishes the inside walls of that bearing race to make it less resistant to wear in the future. After the initial assembly was complete, it put a full wind in it, let it run for about an hour, and then put it on the timegrapher for initial regulation. After about 10 minutes of adjustments, here's where you find out if all the work being put in to the watch was worth it. [ATTACH type="full" alt="21 - After Service & Initial Regulation.JPG"]322746[/ATTACH] As you can see, it's running SO much better. I got it down to 0 to 3 seconds per day in the dial up position, amplitude is excellent at 278 degrees (which tells me that we don't need a replacement mainspring), and the beat error I got down 0.0 – 0.1. I couldn't have asked for better results, but this isn't the end of the work needing to be done to a watch movement after it's serviced. The watch needs to be put on a full wind and ran in for at least 24 hours. This allows the lubricants to settle in the jewels/pivots, for the barrel to unwind and distribute the lubricant, etc. I finished the assembly in the evening, put it on the timegrapher, and left it alone for 26 hours. The s/d reading will always change after it's initial run-in, and the amplitude will drop as the mainspring unwinds over that 24 hour period. The rule of thumb for this type of manual movement is that you want to see amplitude drop to no less than 210 degrees (general rule of 190 degrees on automatics – not counting Japanese movements which are designed to run on lower amplitudes). Although I didn't get a picture of the initial readouts after 24 hours, the s/d had dropped (as expected) to about 9 s/d in dial up, and had been holding steady at that level for quite some time. The amplitude had only dropped to 255, which is fantastic. Now that the movement had been run in, I did a full regulation (in multiple positions). Here's a photo of the same dial up position after everything was said and done, and the watch had been fully reassembled back into the case. [ATTACH type="full" alt="22 - Fully Assembled - Final Timekeeping.JPG"]322747[/ATTACH] I think you've seen enough of these timegrapher readouts to know what looks good and what doesn't. I'll let you be the judge! I'll just say that my hat is off to these old Benrus movements. The readout in the dial down position is very close. Crown left, right, etc. positions saw a drop in amplitude, but everything was working great. FYI – a drop in amplitude from dial up/down to any other position will happen because the watch is on it's side. All of the points of friction on the balance, wheels train, etc. are no longer on the tips of the pivots, but now on the side of the pivots which have a much larger surface area. This creates more friction, which equates to lower amplitude. Even the best watches in the world see this same drop. This why to properly regulate a watch, you have to test it in multiple positions. Dial Up, Dial Down, and Crown Down (position when standing with your arm hanging) are the 3 most used positions a watch well ever be in. The smaller you can make that variance between those positions, the more accurate the watch will keep time while going through the motions of being worn throughout the day. Continued on next post. [/QUOTE]
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