Fitting a new balance staff to a vintage 1940s cyma www military watch. Repair series

you we have here a 1940's cyma World War - military watch and the balance staff is broken as you can see and we're going to replace the balance staff and service this watch now for the purpose of this video I've already stripped down the movement and already cleaned all the parts ready for assembly now that the watch has been cleaned I can start to replace the balance staff in order to replace the balance staff obviously I have to strip down the balance and so this is what I'm going to do now now in manufactured in the 1940s and this is a watch that seen approximately 70 odd years of life and so as you can see there's lots of scratches and dents and dings and all sorts of gremlins so you can see here that the top and bottom pivot is broken on this balance staff before removing their hair spring we have to take a note of where the hair spring studies in relation to the balance wheel and you can see somebody in the past has actually made some marks on the rim here and so I'm just going to leave that as is and use that as my guide now to remove the roller and for the observant among you you might notice that the roller is actually broken and this is the first gremlin or major gremlin that I've come across on this watch and the top and bottom part of the roller are actually split from each other and you can see that somebody though you may say that somebody is actually in the past just squashed it together and so yeah this is something we have to deal with unfortunately parts for this particular caliber are very limited the chance of getting a new roller is is quite difficult so just going to have to do the best I can with this one so in order to remove the roller I'm using a plate X tool or plat ax tool which is my preferred method there are other methods you can use a roller remover this you don't have to beat this or hammer it off it's just a firm push with your fingers will be enough and possibly how it got damaged in the past just be very careful when taking these off and you don't see this in the video but that actually comes off in two parts which it shouldn't do so now I'm taking off the balance staff and for that of reversed the balance wheel in the Playtex tool I'm not doing a tutorial on how to use it a plat ax tool here but needless to say it makes my life a lot easier if anybody wants me to show them how to use a platic tool let me know in the comments and I'll be happy to do a tutorial basically it just breaks the rivet without damaging the balance wheel so now the staff is removed from the balance wheel we can have a look and see what we're up against here yeah so here we are second major gremlin you can see the hole in the middle of the balance wheel there has a quite deep countersink which is highly unusual but here's just to compare the old balance staff with the broken pivots to the new one and you're just going to judge this make sure the balance stuff fits in the hole just nicely and snugly so now we need to set up our tooling and for this we're going to use a staking set any staking set we'll do using a version staking set and it's better to choose the punches that you'll be using beforehand and you need a couple of flat punches and a couple of domed punches and measure them through the hole and need to fit nicely over the new balance staff and also you need to be able to see the edges of the punch through the hole of the balance wheel I'm trying to demonstrate that there so in the stakin set choose the correct size hole for the for the staff and the staff will need to fit nice and loosely in the hole not overly loosely but just find the hole that it doesn't fit into which is this one and go one up there we are now we've chosen the correct hole in the staking set we need to just Center that and then tighten the center the dis taking tool using a centering punch that allows us to do that easily so now the hole is centered as we put the balance staff back in the hole and fit the balance wheel on top of the balance staff now we can start riveting and to start with we need to use the don't punches and the don't punches will spread the river out and spreading out it will actually grip the balance wheel when you tap in the punch you don't have to hit it really hard just a little tap each time will be enough if you hit it too hard you're going to split the balance staff so slowly but surely don't have to rush this part every time you tap it turn the balance wheel maybe 45 degrees just to keep it nice and even and always keep inspecting it but once the wheel is gripping the balance staff excuse it a wide flat punch and don't use a hammer but just press down firmly with your fingers just to make sure that the balance wheel is seated firmly on the on the balance staff and then using your down punch spread out just a little bit more and what you want to do is use the wider domed punch this time to spread out the edges of the rivet you can see I'm not really going to town on hammering away it's just little taps that are required it's quite a lot of force goes through that punch and centers itself right at the bottom so you really don't need to hit it hard just enough to do to spread it out so that it grips the the balance wheel tightly enough and as I say keep inspecting it to make sure that everything looks even and as expected all right once the the river is spread out and is gripping the the balance wheel nicely tightly they use the flat punches and what this does is is it pushes the rivet flat against the balance wheel now I did mention before that there's quite a deep countersink in this particular balance wheel so although I'll get the the rivet straight is not going to look majorly pretty there's there's going to look like there's a gap unfortunately I can't get around that shy of manufacturing a new balance wheel but we don't need to go down that route so now to finish by flattening down the river as as much as possible so you can see that nasty gap between the balanced staff and the the balance wheel but as long as the balance wheel is true and tight on the balance staff we should be fine now to test the N Shake and side shake and trueness of the the balance and just going to put it into the put it onto the movement or with the balance and get a feel for it okay I'm happy with that so now to reassemble the balance we're going to start off by refitting the roller remembering that the roller is damaged so extreme care is required in this particular case because I don't want to make it any worse than it is this is the joy of what's repairing eventually after a lot of tweaking and manipulation I managed to get this roller and fitted correctly so that the timing was not affected by the damage and so now to the the balance spring one important thing to know is that when fitting the roller and the balance spring do not hammer these back on because you are going to cause major damage the only thing you need to do is push them on securely with your fingers and we've not too much pressure only exactly enough pressure needed to drive them through to home now some of you might be thinking why didn't I poise the balance once I fitted the roller and before I fitted the balance spring well there's more than one way to poise a balance and and with this kind of hair spring the best way is to use dynamic poising methods and that's can only be done once the balances back in the watch I'm running as you can see the here's my notes and you can see seven different positions and there's quite at the start there was quite a drastic a man of differential error after adjustment I've managed to get that down to quite a low amount of positional error you've got dial up you got pendant down you got pendant forward where we started made a difference of minus 111 seconds to positive 46 seconds or gaining after a lot of adjustments I've managed to get this down to positive 20 seconds and 2 positive 3 seconds which equates to plus or minus 10 seconds a day and as an average which were a watch of this age I consider to be quite exceptional so this is my video on how to fit a new balanced staff to this vintage cyma watch if you have any questions feel free to post them in the comments below and if you like my videos please subscribe and hit the thumbs up button and you'll be informed when I produced more new content so thanks for watching

Channel: Watch Repair Channel

Views: 309,556

Keywords: watch repairs, watch repair, watch service, mark lovick, watchrepairtalk.com, watchservices.co.uk, Cyma Watches (Business Operation), www, ww2, vintage watch, World War II (Event), 1940s, military watch, balance staff, broken balance, repair balance, repair staff, staking set, staking tool, platax tool, bergeon

Id: vIQvAm4GC5U

Length: 18min 33sec (1113 seconds)

Published: Fri Nov 01 2013