In 1945 my late father-in-law, who was serving in the army at the time, was posted to Nuremberg with the Middlesex regiment to assist in the running of the war crimes trials. At some point during his time there he acquired a Tudor Rolex Oyster watch from the American PX welfare stores. He kept the watch until his death in 2002 and subsequently it passed to his daughter (my wife) who passed it to me a few years later to sort a problem with the keyless works, in the mistaken impression that my skills at the time were up to the job. The watch was running well though, in spite of having spent at least 25 years in a drawer, keeping time to about 20 secs per 24 hrs, but it almost certainly needed a service in addition to repair to the keyless works. This was in 2009 when I had been fiddling with watches for about a year but my initial efforts with this particular watch were somewhat thwarted by my ignorance and trial-by-error approach at the time. The error part of that process resulted in a number of small but significant setbacks which prevented me from completing the repair and service for a further 3 years. The watch as I received it in 2009 was actually in fairly presentable condition:
It’s a classic small oyster-cased watch with screw down crown; about 30mm diameter without the crown, 33.5mm with. Unfamiliar with the back story at the time, I did think it might have been made in the 1940’s but had no real idea. A bit of research suggested that the serial number on the back, a six digit number starting 363… dated the watch to 1945, consistent with the dates my father-in-law was at Nuremberg and suggesting that he bought it new. Opening up the watch, the inside of the case back yields a model number and the manufacturer
In fact the stamps on the inside of the case provide an insight into the nature of watch production at the time, with the parent company RWC Ltd., the Rolex Watch Company Ltd., sourcing the case from the Oyster Watch Company, formerly an independent case maker, which subsequently became a subsidiary of Rolex. In the Tudor branded watches, sub-contracting extended to the movements too, with this one, a FHF 30-1, coming from Fontmelon, and renamed Tudor (or Rolex) 59 when fitted to Tudor and Rolex watches made during this period.
Having done nothing more at this point than open it up, there had been no room for significant foul-ups, but my first, and worst as it turned out, was not far off. My approach at the time was essentially to proceed completely blind. I had no real idea what I was doing but I had a degree of faith that a measured and meticulous approach might compensate for mistakes to some degree and somehow errors could be corrected.
So here’s that first show-stopping novice’s mistake: in starting to dismantle this, my first manual wind movement, I assumed when attempting to loosen the crown wheel screw (see above), that anti-clockwise rotation would do the trick. Unfortunately, the crown screw is left-threaded which means that counter-intuitively, you have to turn clock-wise to undo. In my defence, it required very little torque to persuade the screw head to part company with the thread, but the end result left me with the broken off thread firmly ensconced in the barrel bridge with no immediately obvious means to remove it.
The solution to the problem lies in the different materials used for the bridges and screws in a typical watch movement. The main plate and bridges are generally made from rhodium- or nickel-plated brass but the screws will usually be made of stainless steel. A common watchmaker’s trick for removing broken screws is to immerse the affected bridge in a solution of aluminium potassium sulfate (alum) and wait. The solution is acidic and the hydronium ions will react with the iron in the steel, dissolving it and liberating hydrogen gas but the lower reactivity of the copper in the brass means the bridge is left unaffected. How long you wait depends on the temperature and concentration of the solution and the size of the screw but it is not unusual to have to wait days or even weeks for it to do its job at room temperature. I eventually got around to sourcing some alum from Ebay more than two years after originally breaking the screw.
I made up a saturated solution in hot water and then left the crown bridge immersed for about a week. The screw turned black and eventually I was able to dig it out with the head of a pin. Here’s the partially disassembled movement with the barrel bridge temporarily back in place but with the remnants of the screw successfully removed:
You will notice, however, that the crown wheel ring is missing. Somehow, in the intervening two years between partially dismantling the movement and getting around to rejoining the battle, the ring had gone AWOL along with one of the bridge screws and the screw securing the sweep second cock (see below). My initial approach to sourcing substitutes involved trawling eBay for Fontmelon movements which looked like they might offer up useful parts: I researched likely candidates by referring to the excellent movement database at the Ranfft watches database. This approach yielded a replacement crown wheel ring and a screw for the sweep second cock from an FF150 movement. It would also potentially help with the keyless works repair but see below.
So, finally, in December last year, I set about completing what I had started three years earlier. The starting point then is to begin disassembling the top of the movement: with ratchet wheel removed we see the click spring which sits with one end seated against the click which itself engages with the ratchet wheel.
Next, the barrel bridge comes off which exposes the clutch and winding pinion adjacent to the barrel. The winding pinion pokes through a slot in the barrel bridge and delivers the torque from the turning of the crown to the mainspring via the crown wheel and ratchet wheel.
Before inspecting the dial side of the movement, it’s worth reporting the problem with the keyless works. In order to set the time, conventionally one pulls the crown out to the first click position. In this watch, the stem would not stay in the first position but would spring immediately back to the rest position, and the time could then only be set by holding the crown out whilst rotating it. Turning the movement over again, we see the source of the problem:
The set lever spring has broken with the indented arm which would normally sit against the set lever, sitting somewhere north by north west of its usual location. No problem. The FHF150 will provide a replacement, but that brief flame of hope was quickly extinguished when I inspected the dial side of the spares movement
This one was broken in exactly the same place – obviously a vulnerability in these movements – but in any case the set lever spring from this watch would not have fitted. A perusal of eBay located the correct part from a seller in Canada but an asking price of $85 including postage snuffed out that option in short order. Eventually, some back door foraging of Cousins’ site located the correct part for the princely sum of £5.80.
At this point, most of the movement parts go into the ultrasonic bath for cleaning and then rinsing with the balance spring cleaned with degreaser. Here’s everything (well, almost everything) cleaned and ready for reassembly.
This particular screw appeared to be unavailable through Cousins’ site, and a replacement was not salvageable from the FHF150 because the bridges on that movement are considerably thinner than those on the Tudor 59 and so none of its bridge screws fit. It looked like this past little part of the puzzle would have to remain missing but a careful search of Jules Borel’s site unearthed a possible replacement and so I placed the order and waited with baited breath. A week or so later the usual ‘while you were out’ notice appeared through our letter box and a journey to the sorting office later, yielded amongst a couple of other bits and pieces:
*Edit: For further developments on the crystal front see here.