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Exam results 2017! Watchmaking with the BHI

  1. wsfarrell May 7, 2016

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    Could you expand on "adjust the weight by removing a little material"? Seems to me you could (a) move one of those screws in or out, (b) take a screw out of one hole and put it in another, or (c) sand a screw down slightly to make it lighter (remove a little material). Or something completely different?

    Great stuff!
     
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  2. JimInOz Melbourne Australia May 8, 2016

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    To save Chris some time, here's a great explanation of the process from The Great British Watch Company.

    http://great-british-watch.co.uk/how-to-poise-a-balance-wheel/

    Note: Colin is doing or has done the BHI course too.
     
  3. ChrisN May 8, 2016

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    It's certainly not a daft question and you'd imagine that running in a, relatively, sealed environment it would not get damaged our slip out of balance except if handled poorly during a service. This is a pretty cheap and unsealed watch so it may have been affected by debris in the past. It's also likely been serviced pretty cheaply and has probably been unbalanced for some time. Nowadays, the balances come out of the factory more or less perfect but I suppose it wasn't the same in the 50s.

    I think many of the independent Watchmakers will show you the various timing results. It's unusual for me to do poising but it depends on where you set your acceptable level. In this watch, I'm not too concerned but I try to get the better watches back into specification. For a non chronometer older Omega, it's about 30 seconds variation over all positions.

    I suppose it depends on the person. The course is two years but this poising is probably late in the first year. I've been at this for a few years on my own so I've got a bit of a head start. When it's covered in the course, I'll be looking for any advice as to how to improve the way I do things.

    Only really (b) and (c). The " screws" on that balance didn't have a slot as I suppose they were installed with a pin vice. So, for the two I modified, the best way for me was to cut that slot.

    There's a lot in balance design. Here's the 354 balance which is gorgeous.
    354 balance.jpg
    When you first look, it seems that there are far too many screws needed to poise it. Why didn't they just make the balance more accurately? The clue is in the "Adjusted five positions and temperatures" on the rotor. Most of these screws are for temperature correction and are set at the factory. I don't believe that any Watchmaker regularly adjusts the temperature compensation as it's very involved.

    This is all old technology nowadays and with the latest materials, you don't have any screws so the poising is set as the guy did in the link from Jim.

    Cheers, Chris
     
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  4. Archer Omega Qualified Watchmaker May 8, 2016

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    Hi Chris,

    The screws on the balance are actually for poise in this case - before the advent of modern manufacturing and poising methods, screws were the best method of providing the adjustability needed to eliminate the initial manufacturing errors.

    The temperature compensating balance would be a different animal to the one you show, as it would be bi-metallic construction, and split in 2 places near the arms. It's those two features that make the arms grow or shrink as the temperature varies, changing the moment of inertia of the balance and the timing accordingly. Here is one (on the left) and you can see that the rim of the balance is made of 2 different materials, and the rim is also split:

    [​IMG]

    The temperature compensating balance was replaced by the solid balance (no split rim) when they came up with alloys that were more resistant to thermal expansion, such as the Glucydur material used in most higher end watches these days. Advances in balance spring materials also helped make watches much more stable across a wide range of temperatures.

    Balances sometimes still use screws on higher end watches - for example the Cal. 65 in my GO has them:

    [​IMG]

    Today they are more a sign of a high end or traditional maker than a necessity. Of course some balances have screws only for timing, and not for poise, so Microstella screws on Rolex balances, the Gyromax weights on PP balances, and the screws on the various Omega free sprung balances.

    How you poise a balance depends on the type. On a smooth balance with no screws removing material is really your only choice. If the balance has screws that can be removed, then washers can be added under the screws to add weight in the light area, rather than removing it from the heavy area. I have several selections of timing washers, and they are sorted by the ligne size of the watch you are working on, then in how much time they will change the rate by. In this photo each vial has what look like small specs of dirt in them - those are the washers:

    [​IMG]

    Here is a balance screw I have removed and have added a timing washer to, and it's shown next to a ball point pen for scale:

    [​IMG]

    I will add weight whenever possible because it's easily reversible, but often when you get down to the very fine poising there aren't washers small enough to make the final adjustments, so removing weight is the only way. Adding or removing too much weight can get you into trouble, so slow and steady steps are the best approach, especially when you are just starting out and don't yet have the feel for how much to add/remove.

    How you remove the weight can vary also. For a smooth balance, I use a small pivot drill in a pin vise, and simply use that to remove some material on the underside of the balance rim. For removing weight from screws, the style that removes weight from the underside of the screw is preferred by many, rather than filing the screw down or using the screw cutters are essentially hollow out the head of the screw (and if used a lot will remove the slot from the screw). So this is the preferred technique:

    [​IMG]

    When doing the static poising, the tool has to be level, no drafts in the area (including your breath), and don't level everything up and then lean on the bench while doing your tests. Oh and don't assume there's just one heavy spot! :)

    It's fine work that takes some patience to learn and master, but it's rewarding when you get it done.

    Cheers, Al
     
  5. ChrisN May 8, 2016

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    Thanks Al

    I learnt something there about the temperature compensation. I haven't studied this in detail yet but, I see what you mean. This feedback is much appreciated as I will make some mistakes in interpretation along the way.

    It's a tricky thing to do, as you say, and certainly something that will need a lot of practise before doing on a quality movement where the balance is expensive. I don't come across many that are out of balance in the timing results though but, I know there are ways to compensate with other adjustments.

    I took the easy option of adding a screw slot for this balance as it was a test for me and none had screw slots. I think De Carle shows nine different ways and also does not recommend increasing the screw slot. In this case, there was no slot, just an internal chamfer so, it seemed a useful way to go. As you mentioned, slow and steady is the only way. I think it took me eight or ten attempts to remove the first heavy spot and a few more for a second....

    I've not yet had to do this in anger on any well made movement but will wait until I've a lot more experience before trying it. I have to be aware of my limits at the moment with some of these more complex tasks.

    That's a beautiful movement in your GO.:thumbsup:

    Regards, Chris
     
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  6. Modest_Proposal Trying too hard to be one of the cool kids May 8, 2016

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    Al,

    How often do you have to do these kind of fine adjustments?
     
  7. Archer Omega Qualified Watchmaker May 9, 2016

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    Not on every watch, and static poising is not something I do a lot of in a week, but dynamic poising yes I do a lot of it.
     
  8. gostang9 May 9, 2016

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    +1

    I have a lot of respect for but little knowledge of the inner-workings in mechanical watches. Seeing posts like yours that give us simple common-people a chance to learn and somewhat live vicariously through you is appreciated greatly.
     
  9. ChrisN May 14, 2016

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    Thanks. There's a lot to learn and I hope to keep it interesting. At the moment, I'm full time in my current job so haven't had any time to go through the notes. I did read a lot of this a few years ago but need to refresh my memory.

    Going back to my 354 above. The picture is after I did some adjustments to the hairspring. At the moment, concentricity adjustments are generally within my scope but out of plane are very difficult. I'm hoping during the courses to get some advice about that. Unfortunately, that one was not good at the collet (at the very middle) so, I had to take the spring off and adjust it to stop it kicking up on one side. Gave me the possibility to check the static poise of the balance which was perfect.

    It was a non runner when I bought it and I've bought a few non runners over the last couple of years. Seems like everyone tries to get them running by flicking the balance wheel (all it needs is a bit of a kick and surely that will solve all it's problems...) and they tend to have some hairspring deformation, likely due to that. Here it is from above, without the cock, after fitting back to the balance. It presses on at the collet in the middle (the brass coloured part with the slot in it) and the other end of the spring has a triangular stud which goes into the cock. They don't have a big dog leg in the spring which you seem to see on more modern calibres. They also don't have a movable stud carrier so, to get them in beat you have to turn the collet. It's trial and error and a bit slow to do. That spring is about 5mm diameter but it's surprising how after a time working on something like this, you completely forget how small it is!
    354 spring.jpg

    It's sitting flat and I think it'll be fine but, you have to be pragmatic as this is really hard to judge and the watch is a Chronometer so needs to run in very tight specs. So, I've ordered a new balance complete (balance plus hairspring and stud regulated at the factory). I think these are NLA from Omega but have managed to pick up a NOS one. If in final tests I don't get the results I want, then I'll fit the new balance and spring and keep this one. If not, I've got a complete new spare. It's a learning process and you want to have a backup with this sort of work. In my limited experience you don't usually get these sort of problems though on a watch that just needs a service.

    Somewhere I have a very bent hairspring and might have a go at that, purely as a trial, and show some pictures.

    Anyway, really long week at work and must do a bit of maintenance on my XK so am off the Watchmaking this weekend, more or less.

    Cheers, Chris
     
  10. robocaspar May 15, 2016

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    Very interesting read. Thank you!
     
  11. ChrisN May 22, 2016

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    Another weekend away from this course as far too many other things on but, here's a little detail of the unit D14 which is a first year exam and the various movements need to be in for May next year. My trial with the 354 above has got me going on what to present but there is more detail needed. I also won't be sending that watch off to the assessor as it's pretty unusual and worth a fair amount.
    --------------------------------------------
    Unit D14: The Practical Servicing of Quartz and Mechanical Watches

    This unit is assessed by means of a Record of Repairs

    Servicing a total of ten watches/movements, in each instance, a full service, not just a ‘part job’.

    This should include four quartz movements and six mechanical movements; at least five of the movements must be cased.

    Repair processes to be included

    1. Adjust cannon pinion tightness.
    2. Water resistance testing by two methods and a condensation test.
    3. Clean and oil shock resistant settings, type 1.
    4. Clean and oil shock resistant settings, type 2.
    5. Replace shock resistant springs.
    6. Replace jewels which are friction set.
    7. Adjust end shake, friction jewels.
    8. Use test equipment to diagnose faults in quartz watches.
    9. Use test equipment to diagnose faults in mechanical watches.
    10. Check for faults in lever escapement:
    a. Horn shake: Equal both sides; Less than total lock; greater than run to the banking.
    b. Guard pin shake: Equal both sides; less than or equal to horn shake.
    c. Locking - virtual or drop lock = 1½° or ¼ to 1 ⁄ 5 of pallet impulse face;
    d. Run to banking and draw: ½°; less than horn shake; draw causes lever to return to banking pin.
    11. Correct balance spring faults: Flatness at collet; Flatness at cock; Centering at collet; Curb pins; Beat; Rate
    ------------------------------------------

    Clearly, a fair number of these will be dealt with in the D15 course which will be nice. A couple of pointers to what they're talking about, just 3, 4 and 5 at the moment.

    Two types of shock resistance. The common one is Incabloc (explanation of how they work here) for Omegas but there are many different types out there. They are fitted at the top and bottom of the balance staff and protect the very delicate pivots from breaking when the watch receives a knock. That lyre shaped spring is hooked under the bloc on one side and clips in on the other. To get the jewels out, just release the sides where it clips in and it hinges up out of the way but stays attached.

    Pretty neat unless you have a broken one when you have to remove the complete bloc, hook a new spring under and refit the whole assembly which may mean adjustment of the end float (shake) afterwards. Here's one in the cock of a 561:
    Inca.jpg

    Here's another type used in Mickey. It's a KIF and is easier to work on with regards to replacing the spring as you have to rotate the triangular spring out to get at the jewel anyway...
    5 balance jewel.jpg

    Anyway, something else to think about.

    Cheers, Chris
     
  12. Kobus May 23, 2016

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    Great stuff. Thanks.

    Will that course material be general good reading material if one wants to learn more about the workings of a watch etc, or are there better books on the subject?
     
  13. ChrisN May 23, 2016

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    I'm not sure you'd want to go in that much detail to be honest, especially as the course notes are not cheap. They're more aimed towards making you a Watchmaker.

    I'm open to other peoples opinions here but, I started with De Carle's book which is on Kindle for next to nothing and you can get it immediately.
    de carle.jpg
    It was written some time ago and you'd probably want to start at Chapter 3 but, it's a good reference. 90% of what you likely need to know is in that book.

    Let us know how you get on.

    Hope this helps, Chris.
     
  14. ChrisN May 25, 2016

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    So, I'm jumping about a bit at the moment as I work out what is needed for each of the units. I thought I should investigate this one to see how hard it is.

    Unit D6: Drawing Clock/Watch Escapements
    Another first year exam and it's mainly aimed at helping you to understand how the different escapements work. They're sensible here and start with the simplest, a recoil escapement and then move on to a Graham dead beat. Both of those are used extensively in clocks. The most complex is the third and it's a lever escapement as used in most of our watches.

    You can draw by hand or in Computer Aided Design (CAD). I am going with CAD and am using Computervision DesignView 3. It's a very old and simple 2D system but is parametric and is actually very powerful. It fits on two 1.44 mb floppies which sort of dates it. As it's parametric, I can rotate the various parts and see how they interact which is useful.

    So, the escapement is what releases the power of the main spring. The mainspring is trying to turn the escape wheel all the time (via some intermediate wheels) and the escapement is controlling that release of mainspring power by the interaction between the escape wheel and the pallets. In this recoil design, there is a pendulum attached to the pallet and it's started by moving the pendulum (it's not self starting like a lever escapement). From then, the whole system is driven by the mainspring and the pallet/pendulum receive impulses from the escape wheel which is always trying to turn. In a rough way, the pallet locks the escape wheel so stopping it, then receives an impulse to keep the pallet moving.

    I'm using blue for construction lines and red for dimensions, black for actual parts. The pallet will bridge 7.5 teeth and they'll be 36 teeth on the escape wheel. The escape wheel will turn clockwise so entry pallet on the left and exit on the right.

    The first 7 pictures show how to define the escape wheel teeth.
    1.jpg
    2.jpg
    3.jpg
    4.jpg
    5.jpg
    6.jpg
    7.jpg

    The next 7 define the pallet and the last is with all construction lines removed. As the pallet is drawn when it's just dropped onto a tooth at the entry, it's apparent centre is 2 degrees over. There's only one working face on each pallet (the curved one) so the rest of the pallet is drawn as you wish. The 'drop points' (C and H) are also known as the 'lock points' as they're where the pallet temporarily stops the escape wheel before receiving it's impulse.
    8.jpg
    9.jpg
    10.jpg
    11.jpg
    12.jpg
    13.jpg
    14.jpg
    15.jpg

    The last here is a video of the system working. It's really stop motion animation as it's just a series of screen grabs. I did not model the recoil but, it's clear here and they show the pendulum. This first escapement is just to get you going so, it didn't seem worth trying to be too clever with it as none of the others have recoil. The times shown would be for a 0.5 Hz escapement but the video is much slower. This is the first one I've drawn but it makes sense to me.



    Will draw the dead beat next and then the lever but they get dramatically more complex as you go.

    Hope this is interesting, it was for me.

    Cheers, Chris
     
  15. Kobus May 25, 2016

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    Damn, would like to know more about the mechanics of watches, but this thread shows that there is a lot I can not even comprehend at this stage.

    Great stuff. Will come back here one day.

    :unsure:
     
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  16. ChrisN May 28, 2016

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    Some more practical work now as I finally got around to building my 354 bumper. Thought I'd include some rebuild shots for each watch and here are a few. It's been a bit of a bear to be honest as although it looked superficially good, it had quite a few issues. Anyway, all's well that ends well and it's now running, cased and on my wrist.
    Many thanks to Al for suggestions of how to correct out of plane hairspring problems. It doesn't run to Chronometer specs yet but, I'll wait till I've done more of my course before sorting it. Anyway, 25 seconds variation over six positions would be good enough for a common or garden 354 and this may once have been a chronometer but it is sixty years old so am giving it some leeway. I think I know how to get it there but am not willing to perform that on this movement at the moment.

    Barrel, crown wheel, ratchet wheel and second wheel fitted. Some of the colours here are a bit odd so will need to improve that.

    Build 1.jpg

    Rest of the train fitted and running. Let us never mention this hairspring again (at least I didn't need to use my new complete balance and spring) as it has taken me an age to correct it. Following Al's advice, I try to get the base movement running well before fitting anything else. Conflicting values for the lift angle and am using 51 degrees which is giving 300 degrees of amplitude - very good although it drops to 290 degrees when I fit the additional wheel and the centre seconds pinion.
    Build 2.jpg

    Trial fitting of rotor as the pivots/jewels on these suffer from wear. This one is fine, luckily.
    Build 3a.jpg

    Dial side almost complete and expansion ring fitted (this is a jumbo case).
    Build 4a.jpg

    Dial and hands fitted. I've done nothing to these except brush them off. There's some age staining but looking great. There is a second hand, just a long exposure....
    Build 5a.jpg

    Cased with new crystal and case seal. You might see that the crystal tension ring is yellow gold coloured but, after a lot of effort, I think I've sourced a rose gold crystal and ring so, will replace the ring later. Fails a water resistant test as I can't get a new crown (apparently not even from Omega) however, I might switch out the crown for something else in RG just to solve that. Just a shame to not have the Omega crown.
    Build 6a.jpg
    Completely forgot to take a cased movement shot but can do that another day. And a wrist shot for the hell of it. Just a spare strap and I think it warrants something much nicer.
    Build 7.jpg

    I've learnt a fair bit from this mainly about how to organise myself in a better way as well as getting that hairspring right. I don't find these old bumpers that easy as they can be very worn. A 565 or 1861 is far easier so, have bought a 354 bare movement for my unit D14 above..... (why make life easy!).

    Cheers, Chris
     
  17. TNTwatch May 28, 2016

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    Surprising that it's not documented anywhere even though the 354 appears to be the most common Omega bumper movement!
     
  18. ChrisN May 28, 2016

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    Does seem odd but there is a whole group of these bumpers from 330 to 355. This is what I have, with lift angles on the right.
    lift angles.jpg

    Seems odd they would change the escapement so, I averaged 50 and 52.... Probably not that important as the rule of thumb seems to be that 1 degree on lift equates to about 6 degrees on amplitude. I likely picked that up from Al.

    Cheers, Chris
     
  19. Archer Omega Qualified Watchmaker May 28, 2016

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    Nice work Chris.

    Just to confirm, the lift angle for the 354 is 50 degrees. Same for the 330, 340, and 350 series of movements. Your amplitudes are still good. Of course few watch companies provide a minimum amplitude at full wind, and more state what the minimum should be at full wind +24 hours. For this one they require it to be 180 degrees minimum...for me that's too low but I don't think yours would drop that low anyway based on your full wind numbers.

    I think Omega recognizes that these older calibers are going to have a lot of wear and other problems. Many parts for these are no longer available - I had to scrounge an escape wheel for one I'm working on right now to replace the worn out wheel for example because Omega no longer supplies these. The tolerances Omega has for these currently are pretty generous you could say. They allow 40 seconds of Delta over 3 positions at full wind, and 50 over 3 positions at full wind +24 hours. So your readings are well within what Omega deems acceptable for these. Of course these are just a starting point for most watchmakers.

    Once again glad you found my balance spring adjusting advice helpful.

    Cheers, Al
     
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  20. JimInOz Melbourne Australia May 28, 2016

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    Great Sunday morning reading, although escape geometry will have me thinking hard. Thanks Chris, good to see you progressing, looking forward to more.