In a time when everything has to move faster and faster, it's a true pleasure to watch a two-hour video that simply delves into a single topic. And that's exactly what makes it so engaging and captivating. Thank you so much for the effort you put into creating this for us.
Thanks Klaus for your kind feedback. Yes I realised when editing I should leave in quite a bit of the repetition (removing/replacing screws etc) as that has a meditative quality. Glad you enjoyed it. Matthew
This is a fantastic video. It’s so very rare to see someone do a video on cleaning one of these. These are some of the best clocks that were ever made, and for good reason. And I hope that they continue to stand the test of time. I personally own a Hamilton model 21, and the workmanship is just stellar.
Thank you for your kind feedback. Yes, I have been looking for an instrument like this for some time. As you say, beautiful quality. If they were wristwatches, they would be worth a lot more! :=) Matthew
Thankyou Mathew for a full feature video of you doing wonderful work, I enjoyed every minute of it. The filming and description is excellent. Giving us your trade secrets is much appreciated.
Matt, this was another fantastic restoration-always a pleasure to watch your process! Your channel definitely deserves more views because I learn something new each time I tune in. I was particularly amazed at how beautifully finished the components are, especially considering that they’re enclosed in brass and protected by a box-this truly showcases the “insanity” of watchmaking. Around the 43:17 mark, I noticed those little dimples in the wheel and couldn’t help but wonder-are they for poise? Another question on my mind: do you think older mainsprings become “set” over time, eventually losing their optimal pairing with the fusee cone? I’m also curious about the advantages of fully disassembling the balance spring and compensating weights. I’d be worried about getting the weights back to their exact factory positions, even with a sketch to guide the reassembly. Though, as you mentioned, the impact might be minimal for a piece that will mostly sit on a desk at room temperature. Lastly, I’m glad to see I’m not the only one who occasionally forgets to replace the maintaining power detent on reassembly-it’s comforting to know that even experienced watchmakers can overlook it! Keep up the great work, and I look forward to your next video.
Hi Chris Thanks for your kind feedback. Yes, chronometers are so unfeasibly beautifully finished. They are the actual 'high art' of horology. The earlier ones and pocket chronometers from the early 19th century are mind-blowing. Highly recommend you get one to work on at some point. Fiddling with the detent escapement is also fun. The marks at 43:17 are batch marks. You get this on French clocks too where there are I think up to six instruments on the bench and as the caliber moved from the grey to being finished, the batch marks were added to keep the finished components with the correct frame. Looking closely at the marks you often find a code within the marks, say one dot and three dots or arranged in a particular way. Older chronometers also often have small triangular marks on the underside of flat-finished components. This is where they were held with the tip of a graver on the zinc plate. The mainspring question is a very good one. Yes springs change over time. The rule of thumb that describes a 'set' spring (develops to twice the diameter of the barrel?) can in my unpopular opinion be discounted. It is at beast a rule of thumb. Much of my time is spent fitting weaker springs to fusee clocks where older, perfectly fine springs have been unnecessarily replaced. I think one of my videos on the spring clock addresses this? Your question is a really good one. I dont think 19th century springs in domestic clocks were individually matched to fusee cones; they were just in the ball-park. Yes, earlier precision instruments were matched with a fusee rod with sliding weight. I think it was Thomas Earnshaw who describes scraping down the mainspring to achieve one that develops uniformly. I imagine trying to match a modern mainspring with a relatively flat torque curve to an old fusee is a greater 'evil', than just keeping the old spring. I bought an inexpensive digital torque screwdriver which turned out to be incredibly useful in this regard. With the chronometer and its relatively isochronous balance spring, variations in power output shouldn't make a massive difference to timekeeping. Once the first 24 hour period has passed, the wider-view takes over and short-term variation becomes less meaningful. With a domestic clock with anchor recoil escapement you are likely to see a losing rate due to escapement error towards the end of a week where the spring is less lively. Again this can usually be regulated out with a slight gaining rate in the long arcs. I'm no watchmaker but remember in the old days, the index pins were manipulated to account for the 'long' and 'short' arcs. Good question. More research needed! :=) I have seen watchmakers remove all the screws from a screwed balance but think it is reasonable practice to leave the screws in place (watch) and the balance spring on. Over time the balance will probably lose mass through cleaning resulting in a gaining rate but the balance spring will lose mass/section too and work-harden so another good question. In the case of this chronometer and domestic clocks, reasonable fullest dissasembly is again I think a lesser 'evil' than trapped cleaning fluid. The balance weights were not marked and although I put them back in different positions (my bad) if anyone in future wants to rate the machine in heat and cold and change the amount of compensation, it's not a big deal (I think :=)). Thanks agin for your kind feedback and encouragement to keep going with the vids. As an aside, I bought the chronometer at a local auction here in the North of England. It was pretty 'grotty'. Just sold it, got my money back and it is off to a collector in Germany. Heading home so a happy ending. Kind regards, Matthew
Another great video.The decision to lightly clean the Dial definitely was the right one in this case. Would be keen to see another video on something with a ton of issues-similar to #001 the Verge Pocket Watch-but even worse off.Do you have anything like that in the works? Many thanks for the content.Kind regards.Aaron
Thanks Aaron, appreciated. Plenty projects in the pipeline, just takes me a while to get round to them with other work etc! Keep watching and if you havent already, please check out my other channel, how to repair pendulum clocks. M
Hi Matthew, great close up photography as usual, what magnification are you typically using?, I never get such clear shots with my mobile set up, time to upgrade I think! Thanks for your earlier videos on pallet refacing, it helped me to successfully have a go myself on my latest project
Hi David. Thank you. I would say next steps are better lights. Good because you can use them for work lights too and general photography. I use the three light LED panel set from Viltrox. They are dimmable and adjustable for colour temperature. You will find your phone performs a lot better when there is more light. Yes, when you have the funds, there are lots of cameras. Many of the watch youTubers use a Amscope digital microscope. I use a FujiFilm X-T4 with an 80mm macro lens for close-up work. I think the more you do the better the outcome. M
Hi Mark. De-ionised water and a very small amount of detergent to act as a wetting agent. Rinse (soak) the cleaned dial in de-ionised water at least twice then dry really thoroughly, especially if lacquering. Matthew
Thanks very much for showing this superb clock. The face cleaned up very well, not too clean but much better than it was. Do you put any protection onto the brass plates at all?
Thanks for your kind feedback. Yes you can apply a small amount of microcrystalline wax to deter tarnishing. Put it on the brush first then on the plate and keep it out of the bearings. M
That's a good question and exactly the reason I began using it. When I was a student the workshop was plagued with clocks, particularly fusee dial clocks, the mainsprings of which would periodically and alarmingly judder. I started using this product over 20 years ago and never looked back. Certainly worth a try. The other thing I would say is only clean mainsprings in oil-based solvents, never water-based. New mainsprings can have a finely ground surface so I go over them with very coarse abrasive paper (wash thoroughly afterwards) to create a space for some lubricant to remain. Older springs not a problem as they tend to have a much less uniform surface. Not sure about a US supplier. I would just drop the distributor a line. chemodex.co.uk Hope this helps. Matthew. PS. I have seen clock springs lubricated with the car type molybdenum grease. The issue here is the solids and the liquid oil separate out. M
I've seen a guy use denture cleaning tablets to get the clock faces clean and it works to the extent of getting them pearly white he just leaves them in overnight
Just a note on a few things that are probably best NOT done during simple a chronometer cleaning. First, it isn't necessary, or advisable, to remove the passing spring from a detent just for cleaning. The only time a detent should be disassembled is if it is in need of repair or adjustment. Perfectly positioning the passing spring is a tricky procedure best left to someone with lots of experience adjusting detent escapements. If you look at the before and after pictures here, you'll notice that after you replaced it, the spring was no longer in alignment with the blade of the detent. That makes the tip address the unlocking jewel at an angle. That's not ideal. The same advice can be applied to the detent banking screw. There's no point or purpose in touching that screw unless the banking needs adjustment. Also, those threads don't get oiled. You don't want any extra oil anywhere near the escapement. The banking screw is supposed to be tight. The banking block is slit to make that screw tight in its hole. That's because the banking screw gets banged eccentrically once per second. It needs to be tight, with no risk of moving on its own. Continuing along the same vein, it's also not usual practice to move, let alone remove, any of the balance weights during a normal cleaning. If you look at the burned-in fingerprints in the before and after pictures, you'll notice that you've swapped the positions of several of the compensation weights. Someone in the factory spent a LOT of time establishing the original positions and maintaining the overall balance poise. Why fiddle with any of that? It's best practice to treat the balance the same way you'd treat the balance spring with its stud and collet--as a single unit that doesn't ever get disassembled. If the balance is cleaned in modern watch rinsing solution and carefully dried, it doesn't need to be touched at all.
Thanks for your feedback. I would broadly disagree that clocks should not be disassembled for cleaning. I have seen many - dozens - of examples in my practice where lack of disassembly has led to corrosion between components. In this case, I used watch cleaning solution containing ammonia in an attempt to mitigate the finger-prininting. Essential I would say, that within reason, everything that was designed to be disassembled; is. An exception to this may be removing the screws from a wristwatch balance (although I have seen some people do this). I'm not sure it is clear in the video but of course I did align the passing spring before fitting the detent back into the frame, I just didn't film or edited out that process. In-fact, in the shots immediately following re-fitting the spring, you can clearly see I have adjusted it. The small amount of oil on the thread of the banking screw is to prevent galling in brass-in brass bearings. Again, I would say, as part of an overhaul, removing the screw is no problem and yes I understand it needs to be snug. I do however agree that putting the weights back in the position before I removed them would have been better, or at least mentioning it. I saw no markings on them, and where everything else in the machine is marked, I presume if the finisher wanted repairers to maintain the orientation, they would have marked them? Maybe not. We have no way of knowing whether they have already been moved, there are multiple marks on the rim where they have been moved to adjust the amount of compensation. I will check them for marks. Thanks again for taking time to make comments. Wishing you a Happy New Year. Matthew
@@readrepairs Who made any claim that "clocks should not be disassembled for cleaning"? The instrument in the video is a precision timekeeper, not a kitchen clock. On a chronometer most parts should be disassembled to their constituent elements, but not ALL. If, as you contend, everything that can be disassembled should be taken apart during a basic cleaning, then why didn't you un-pin the balance spring and clean the collet and stud separately? The same can be said of the rollers. They're designed to come off the staff. And if a clean staff concerns you, the hub can also be easily removed. Getting the jewels out of the rollers is pretty easy too. Why would you do any of those things, though? Chronometers aren't clocks. Not EVERYTHING needs to be taken apart to be properly and professionally cleaned. Some elements are designed to be cleaned as sub-assemblies. Complete disassembly of those sub-assemblies introduces potential performance problems, or flat-out courts disaster. As I said before, it is NOT normal to remove the passing spring when cleaning a detent. And yes, the banking piece in this chronometer has a threaded body and a slotted head. So it fits the common definition of a "screw". Just because it looks like a "screw" to an untrained eye, however, that doesn't mean that it is designed to be taken out and put back in. Do you remove banking pins from precision lever escapements in order to clean those, just because they sometimes have threaded bodies, slotted heads and resemble screws? After being set at the factory, most banking pieces don't make a single rotation in the entire life of the instrument, even if the machine is serviced every year. They live stationary lives. Galling is not an issue. Misadjustment, on the other hand, introduces all kinds of unnecessary risks and performance issues, as does potential oil migration right at the locking jewel. Regarding balance cleaning, yes improper cleaning solutions and improper procedures (e.g. failures to neutralize, rinse and dry) can encourage corrosion between the weights and the rim. That's a real issue that has damaged innumerable chronometer balances in the era of liquid bath cleaning. The answer to this potential problem, however, isn't complete disassembly, which disregards/discards all of the effort and expertise that specialists poured into setting up and adjusting that balance. A Guillaume balance isn't a clock pendulum, or even a Pennington-style screw design, where the construction facilitates disassembly and reassembly. Do you want viewers to think that sliding compensation weights should routinely be fiddled with during a basic cleaning, and that nothing could possibly be lost by removing them and swapping them around, as long as they get back to positions that "look" close to where they were originally? That's not a normal procedure, or best practice, as far as chronometer cleaning/conservation/restoration is concerned.
In a time when everything has to move faster and faster, it's a true pleasure to watch a two-hour video that simply delves into a single topic. And that's exactly what makes it so engaging and captivating. Thank you so much for the effort you put into creating this for us.
Thanks Klaus for your kind feedback. Yes I realised when editing I should leave in quite a bit of the repetition (removing/replacing screws etc) as that has a meditative quality. Glad you enjoyed it. Matthew
Fabulous work
@@joshuapepper7521 Thank you!
Yay, another video! 🤗👍
Thks Matt, youre a true craftsman. Very rare these days. Tell me do you ever use an ultrasonic cleaner to clean parts?
That's very kind. Thanks for your feedback. No, I dont use an ultrasonic due to the risk of cavitation/erosion. I just clean by hand. M
This is a fantastic video. It’s so very rare to see someone do a video on cleaning one of these. These are some of the best clocks that were ever made, and for good reason. And I hope that they continue to stand the test of time. I personally own a Hamilton model 21, and the workmanship is just stellar.
Thank you for your kind feedback. Yes, I have been looking for an instrument like this for some time. As you say, beautiful quality. If they were wristwatches, they would be worth a lot more! :=) Matthew
What a great video Matthew. I love the lighting and camera work.
Thanks Tommy, appreciated. M
Superb video. You are a highly skilled watchmaker. Some watchmakers will not touch a detent escapement. Well done and a pleasure to view.
Nice sympathetic overhaul ,beautiful filming 😊,
Well done !
Thank you Daryn! Appreciated, Matthew
That was another great video Matthew. Watching 2 hours of such a service is pure joy. Seen every second of it! Thanks for making and sharing it!
Thanks Franklin. As always, your support appreciated. It was a bit of a marathon! M
Thankyou Mathew for a full feature video of you doing wonderful work, I enjoyed every minute of it. The filming and description is excellent. Giving us your trade secrets is much appreciated.
Thanks John for your kind feedback. M
Enjoyed, never seen these being serviced thank you.
Glad you enjoyed it.
Thank you. A fantastic video. Above my pay grade, but it is always useful to extend knowledge.
Thanks Duncan. Yes, you never know when this stuff will come in handy? Happy New Year, M
Excellent video. Your teaching, horological and video skills are amazing. Thank you so much. I learn something new every time.
Thanks Brian for your kind feedback. Glad you enjoyed it. Happy New Year. M
Nice work as usual Matthew beautiful clock
Thanks Dell! Hope you are well. Wishing you a Happy New Year. M&R
@ yes Matthew enjoying retirement, Happy new year to you & Rachel
Thank you @torsiondell!!
Wow, this is a marvel. Thanks for sharing. it's very interesting ! 😊🇨🇦
Thank you! glad you enjoyed!
Matt, this was another fantastic restoration-always a pleasure to watch your process! Your channel definitely deserves more views because I learn something new each time I tune in. I was particularly amazed at how beautifully finished the components are, especially considering that they’re enclosed in brass and protected by a box-this truly showcases the “insanity” of watchmaking.
Around the 43:17 mark, I noticed those little dimples in the wheel and couldn’t help but wonder-are they for poise?
Another question on my mind: do you think older mainsprings become “set” over time, eventually losing their optimal pairing with the fusee cone? I’m also curious about the advantages of fully disassembling the balance spring and compensating weights. I’d be worried about getting the weights back to their exact factory positions, even with a sketch to guide the reassembly. Though, as you mentioned, the impact might be minimal for a piece that will mostly sit on a desk at room temperature.
Lastly, I’m glad to see I’m not the only one who occasionally forgets to replace the maintaining power detent on reassembly-it’s comforting to know that even experienced watchmakers can overlook it! Keep up the great work, and I look forward to your next video.
Hi Chris
Thanks for your kind feedback. Yes, chronometers are so unfeasibly beautifully finished. They are the actual 'high art' of horology. The earlier ones and pocket chronometers from the early 19th century are mind-blowing. Highly recommend you get one to work on at some point. Fiddling with the detent escapement is also fun. The marks at 43:17 are batch marks. You get this on French clocks too where there are I think up to six instruments on the bench and as the caliber moved from the grey to being finished, the batch marks were added to keep the finished components with the correct frame. Looking closely at the marks you often find a code within the marks, say one dot and three dots or arranged in a particular way. Older chronometers also often have small triangular marks on the underside of flat-finished components. This is where they were held with the tip of a graver on the zinc plate. The mainspring question is a very good one. Yes springs change over time. The rule of thumb that describes a 'set' spring (develops to twice the diameter of the barrel?) can in my unpopular opinion be discounted. It is at beast a rule of thumb. Much of my time is spent fitting weaker springs to fusee clocks where older, perfectly fine springs have been unnecessarily replaced. I think one of my videos on the spring clock addresses this? Your question is a really good one. I dont think 19th century springs in domestic clocks were individually matched to fusee cones; they were just in the ball-park. Yes, earlier precision instruments were matched with a fusee rod with sliding weight. I think it was Thomas Earnshaw who describes scraping down the mainspring to achieve one that develops uniformly. I imagine trying to match a modern mainspring with a relatively flat torque curve to an old fusee is a greater 'evil', than just keeping the old spring. I bought an inexpensive digital torque screwdriver which turned out to be incredibly useful in this regard. With the chronometer and its relatively isochronous balance spring, variations in power output shouldn't make a massive difference to timekeeping. Once the first 24 hour period has passed, the wider-view takes over and short-term variation becomes less meaningful. With a domestic clock with anchor recoil escapement you are likely to see a losing rate due to escapement error towards the end of a week where the spring is less lively. Again this can usually be regulated out with a slight gaining rate in the long arcs. I'm no watchmaker but remember in the old days, the index pins were manipulated to account for the 'long' and 'short' arcs. Good question. More research needed! :=)
I have seen watchmakers remove all the screws from a screwed balance but think it is reasonable practice to leave the screws in place (watch) and the balance spring on. Over time the balance will probably lose mass through cleaning resulting in a gaining rate but the balance spring will lose mass/section too and work-harden so another good question. In the case of this chronometer and domestic clocks, reasonable fullest dissasembly is again I think a lesser 'evil' than trapped cleaning fluid. The balance weights were not marked and although I put them back in different positions (my bad) if anyone in future wants to rate the machine in heat and cold and change the amount of compensation, it's not a big deal (I think :=)).
Thanks agin for your kind feedback and encouragement to keep going with the vids.
As an aside, I bought the chronometer at a local auction here in the North of England. It was pretty 'grotty'. Just sold it, got my money back and it is off to a collector in Germany. Heading home so a happy ending.
Kind regards, Matthew
Great job
Thank you!
Thanks Darren for your kind feedback. Appreciated. It did make me nervous!
Your the best of the best!!!
Thank you :=)
Pure gold what a privilege to see your work thank you and a happy and peaceful new year to you
Thank you. Same to you.
Happy new year Matthew ❤
Happy New Year to you John. Matthew
After 40 years of sextant, barometer, binocular, microscope and telescope repairs, I developed the same paranoia! Nice job.
Ha! Thank you! Glad it is not only me :=) Happy New Year, Matthew
brilliant ! Thanks a lot
Thank you! :=)
Beautiful smile mate!
Another great video.The decision to lightly clean the Dial definitely was the right one in this case.
Would be keen to see another video on something with a ton of issues-similar to #001 the Verge Pocket Watch-but even worse off.Do you have anything like that in the works?
Many thanks for the content.Kind regards.Aaron
Thanks Aaron, appreciated. Plenty projects in the pipeline, just takes me a while to get round to them with other work etc! Keep watching and if you havent already, please check out my other channel, how to repair pendulum clocks. M
Hi Matthew, great close up photography as usual, what magnification are you typically using?, I never get such clear shots with my mobile set up, time to upgrade I think!
Thanks for your earlier videos on pallet refacing, it helped me to successfully have a go myself on my latest project
Hi David. Thank you. I would say next steps are better lights. Good because you can use them for work lights too and general photography. I use the three light LED panel set from Viltrox. They are dimmable and adjustable for colour temperature. You will find your phone performs a lot better when there is more light. Yes, when you have the funds, there are lots of cameras. Many of the watch youTubers use a Amscope digital microscope. I use a FujiFilm X-T4 with an 80mm macro lens for close-up work. I think the more you do the better the outcome. M
great video- what did you mix with the tarter when cleaning the hands and dial ?- thanks
Hi Mark. De-ionised water and a very small amount of detergent to act as a wetting agent. Rinse (soak) the cleaned dial in de-ionised water at least twice then dry really thoroughly, especially if lacquering. Matthew
@@readrepairs thanks again !!
Thanks very much for showing this superb clock. The face cleaned up very well, not too clean but much better than it was. Do you put any protection onto the brass plates at all?
Thanks for your kind feedback. Yes you can apply a small amount of microcrystalline wax to deter tarnishing. Put it on the brush first then on the plate and keep it out of the bearings. M
Dose this moly spray (LQG Moly Liquid Multi-Purpose Lubricant Grease 500ml Aerosol) prevent lurching main springs and how can I get some on the US?
That's a good question and exactly the reason I began using it. When I was a student the workshop was plagued with clocks, particularly fusee dial clocks, the mainsprings of which would periodically and alarmingly judder. I started using this product over 20 years ago and never looked back. Certainly worth a try. The other thing I would say is only clean mainsprings in oil-based solvents, never water-based. New mainsprings can have a finely ground surface so I go over them with very coarse abrasive paper (wash thoroughly afterwards) to create a space for some lubricant to remain. Older springs not a problem as they tend to have a much less uniform surface. Not sure about a US supplier. I would just drop the distributor a line. chemodex.co.uk Hope this helps. Matthew. PS. I have seen clock springs lubricated with the car type molybdenum grease. The issue here is the solids and the liquid oil separate out. M
@@readrepairs thank you, Matthew, I sure enjoy your content. Cheers!
I've seen a guy use denture cleaning tablets to get the clock faces clean and it works to the extent of getting them pearly white he just leaves them in overnight
Worth try! ? :=) M
Just a note on a few things that are probably best NOT done during simple a chronometer cleaning. First, it isn't necessary, or advisable, to remove the passing spring from a detent just for cleaning. The only time a detent should be disassembled is if it is in need of repair or adjustment. Perfectly positioning the passing spring is a tricky procedure best left to someone with lots of experience adjusting detent escapements. If you look at the before and after pictures here, you'll notice that after you replaced it, the spring was no longer in alignment with the blade of the detent. That makes the tip address the unlocking jewel at an angle. That's not ideal. The same advice can be applied to the detent banking screw. There's no point or purpose in touching that screw unless the banking needs adjustment. Also, those threads don't get oiled. You don't want any extra oil anywhere near the escapement. The banking screw is supposed to be tight. The banking block is slit to make that screw tight in its hole. That's because the banking screw gets banged eccentrically once per second. It needs to be tight, with no risk of moving on its own. Continuing along the same vein, it's also not usual practice to move, let alone remove, any of the balance weights during a normal cleaning. If you look at the burned-in fingerprints in the before and after pictures, you'll notice that you've swapped the positions of several of the compensation weights. Someone in the factory spent a LOT of time establishing the original positions and maintaining the overall balance poise. Why fiddle with any of that? It's best practice to treat the balance the same way you'd treat the balance spring with its stud and collet--as a single unit that doesn't ever get disassembled. If the balance is cleaned in modern watch rinsing solution and carefully dried, it doesn't need to be touched at all.
Thanks for your feedback. I would broadly disagree that clocks should not be disassembled for cleaning. I have seen many - dozens - of examples in my practice where lack of disassembly has led to corrosion between components. In this case, I used watch cleaning solution containing ammonia in an attempt to mitigate the finger-prininting. Essential I would say, that within reason, everything that was designed to be disassembled; is. An exception to this may be removing the screws from a wristwatch balance (although I have seen some people do this). I'm not sure it is clear in the video but of course I did align the passing spring before fitting the detent back into the frame, I just didn't film or edited out that process. In-fact, in the shots immediately following re-fitting the spring, you can clearly see I have adjusted it. The small amount of oil on the thread of the banking screw is to prevent galling in brass-in brass bearings. Again, I would say, as part of an overhaul, removing the screw is no problem and yes I understand it needs to be snug. I do however agree that putting the weights back in the position before I removed them would have been better, or at least mentioning it. I saw no markings on them, and where everything else in the machine is marked, I presume if the finisher wanted repairers to maintain the orientation, they would have marked them? Maybe not. We have no way of knowing whether they have already been moved, there are multiple marks on the rim where they have been moved to adjust the amount of compensation. I will check them for marks. Thanks again for taking time to make comments. Wishing you a Happy New Year. Matthew
@@readrepairs Who made any claim that "clocks should not be disassembled for cleaning"? The instrument in the video is a precision timekeeper, not a kitchen clock. On a chronometer most parts should be disassembled to their constituent elements, but not ALL. If, as you contend, everything that can be disassembled should be taken apart during a basic cleaning, then why didn't you un-pin the balance spring and clean the collet and stud separately? The same can be said of the rollers. They're designed to come off the staff. And if a clean staff concerns you, the hub can also be easily removed. Getting the jewels out of the rollers is pretty easy too. Why would you do any of those things, though? Chronometers aren't clocks. Not EVERYTHING needs to be taken apart to be properly and professionally cleaned. Some elements are designed to be cleaned as sub-assemblies. Complete disassembly of those sub-assemblies introduces potential performance problems, or flat-out courts disaster. As I said before, it is NOT normal to remove the passing spring when cleaning a detent. And yes, the banking piece in this chronometer has a threaded body and a slotted head. So it fits the common definition of a "screw". Just because it looks like a "screw" to an untrained eye, however, that doesn't mean that it is designed to be taken out and put back in. Do you remove banking pins from precision lever escapements in order to clean those, just because they sometimes have threaded bodies, slotted heads and resemble screws? After being set at the factory, most banking pieces don't make a single rotation in the entire life of the instrument, even if the machine is serviced every year. They live stationary lives. Galling is not an issue. Misadjustment, on the other hand, introduces all kinds of unnecessary risks and performance issues, as does potential oil migration right at the locking jewel. Regarding balance cleaning, yes improper cleaning solutions and improper procedures (e.g. failures to neutralize, rinse and dry) can encourage corrosion between the weights and the rim. That's a real issue that has damaged innumerable chronometer balances in the era of liquid bath cleaning. The answer to this potential problem, however, isn't complete disassembly, which disregards/discards all of the effort and expertise that specialists poured into setting up and adjusting that balance. A Guillaume balance isn't a clock pendulum, or even a Pennington-style screw design, where the construction facilitates disassembly and reassembly. Do you want viewers to think that sliding compensation weights should routinely be fiddled with during a basic cleaning, and that nothing could possibly be lost by removing them and swapping them around, as long as they get back to positions that "look" close to where they were originally? That's not a normal procedure, or best practice, as far as chronometer cleaning/conservation/restoration is concerned.