Advice with tight bridges

[Neverenoughwatches]

Eyup world, morning UK. Just thought i would play out some advice for beginners with the common issue of tight bridges and cocks. Prompting me to do this from a particularly stubborn example of this problem last night. This is a regular occurance on vintage swiss, in fact around 60 percent of the watches i come across have at least one bridge or cock that doesn't fall into place nicely. Oris is especially typical of this. I know tolerances need to be tight for correct gear meshing and exact side shake between all pivots but some can be a real shit to get back on. Wrestling with the tight placement of a bridge can often lead to bent or broken pivots especially for beginners that are still feeling their way around a movement. So last night's restoration gave me probably one of the worst I've had for ages, a tight train bridge with a bent escape wheel pivot luming. I really like the watch and didn't fancy trying to source a new part as thats another crossed off the list of ever decreasing availability of them. So i decided to take my time ( almost an hour in fact) and well worth it imo ( never rush repair especially when you are getting frustrated, particularly applicable to me as a have a short fuse at times. ) So before assembly do a quick dry run of the bridges. The barrel ( great wheel or first wheel ) bridge generally isn't a problem as you have a little more tolerance here and a large tough arbor thats not easily damaged ( unless you are built big and clumsy like the Hulk, in which case why are you repairing watches ? ). Its usually the train bridge and sometimes the balance cock that causes problems. The more difficult ones are where you cant see the locating studs next to the screw holes. Instead of a through stud hole on the bridge where you can see the stud on the mainplate there is a shallow blind hole or the stud is on the underside of the bridge fitting to a hole in the mainplate. So test your bridges dry ( no train wheels ) and if they are tight work them on and off for a while ( nearly an hour yesterday ) . And if still necessary the tiniest smear of grease before the final assembly of the train. With out that easing off a bent or broken pivot is very possible, usually the escape wheel ( i would lay money down that everyone has done it ) The balance cock is also susceptible to this, some have as many as 3 studs in an obviously very close proximity to each other so tolerances can be pretty tight here to keep things right. Removing cap jewels and chatons would be a good course of action if the cock is tight, to give the staff pivots a bit of wiggle room while you perform. A broken balance staff pivot is a real pain in arse, and for beginners often requires another assembly complete. Dont be tempted to  broach out stud holes its very risky. Pros i would think can get away with smooth broaching, I've even done it myself on occasion, but personally not something that should be recommended to a beginner. The on and off method would be a much safer bet if the bridge is especially tight. So there you go, my little input for the day, I'm  off to do a bit of plastering now, catch you all later. X

[Mark]

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