A somewhat unsatisfying consequence of the most recent 62MAS project, documented here, was the fact that a perfectly decent 6217A movement appeared to have become surplus to requirements.
However, I’d always had in mind that I’d be able to recycle what looked to me a very clean and tidy movement by handing it down to my first 62MAS (described here) whose movement had lived a much harder life and which, to be honest, was really past the point where it might reasonably be expected to put in another extended period of service. The problem with that particular movement was what watchmakers refer to as excessive barrel arbor side shake. The telltale clue provided at the time I serviced it back in late 2011 was a badly worn barrel arbor hole in the main plate which was sporting the characteristic horse shoe imprint of a watchmaker who had tried to close the hole back up.
Unappreciated at the time (although obvious if you think about it) was that in addition to a worn hole in the main plate, the barrel arbor hole in the train wheel bridge was equally worn.
You should be able to see in the photo above that the originally circular hole has acquired more of an oval aspect, with the wiggle room thus provided allowing the arbor and barrel to rock and roll during their rotational period to the extent that the teeth on the lower part of the barrel were rubbing against the underside of the centre wheel bridge. Judging from the condition of the bridge, the side shake had become so bad that the watchmaker had resorted to removing material to provide sufficient clearance to accommodate the side shake.
I ended up replacing the bridge, smoothing off the ragged barrel hole in the main plate and hoping for the best. In the end, the movement ran smoothly – in fact surprisingly well and without issue in the intervening period. Here it is running quite happily before being refitted to the watch back in 2012.
However, it does not take much effort to demonstrate the considerable slack in the location of the barrel arbor. Pressing the barrel down on the side closest to the centre wheel sees the teeth of the barrel explore the lower reaches of the centre wheel pinion:
whilst pushing down on its outer edge lifts the teeth perilously close to the underside of the replacement centre wheel bridge, potentially slowing or even jamming the movement:
So, the recent availability of a donor movement liberated from the new intake suggested the time was right the put this knackered old workhorse out to pasture and inject some fresh vigour back into an otherwise very tidy watch. The donor 6217A pre-clean looked very tidy indeed, with not much rotor wear evident around the edges of the main plate or balance cock:
A quick look at the calendar side of the replacement movement confirms the presence of the often missing hour wheel ring which raises the effective height of the hour wheel to allow the dial washer to come into contact with the reverse of the dial, thereby holding the hour wheel in place:
Its presence is necessary in this case because of the cutout in the date dial guard required to provide clearance for the pinion on the top of the minute wheel (required in World Timers fitted with this movement). The date dial guard fitted to date only 6205’s and indeed the earlier 395 used as the basis of the hot-rodded 62MAS, does not need to clear a minute wheel pinion and so has no such cutout. In those cases, the date dial guard itself keeps the hour wheel in position and not the dial.
The dismantling, cleaning and reassembly of this 6217 proceeded without incident. Importantly, the main plate barrel arbor hole, whilst contaminated with leeched mainspring grease, showed only a little bit of wear to the nickel plating on one side of the hole
whilst the upper hole in the train wheel bridge looked largely unworn. Here is a view during reassembly:
Although nothing much looked like it obviously needed replacing, I took the precaution nonetheless to replace the centre wheel and cannon pinion, fit a new barrel arbor and replace the setting lever and setting wheel lever complete, the latter to mitigate against a well-known potential problem with setting wheel lever wear common in all 62xx movements featuring a calendar. Here’s a quick view of the reinvigorated movement in its new home.
Following a few minutes of regulation and with the mainspring at something approaching fully wound I was rather astonished to see the amplitude exceeding 300 degrees. Currently, it is running at +1 s/d 290 degrees amplitude and 0.0 ms beat error, dial down; +5 s/d 291 degrees 0.1 ms, dial up; and +4 s/d 276 degrees 0.2 ms crown down. Not bad for a watch born in May 1966 (coincidentally, the same birth month as the watch providing the hand-me-down).
I’ve had this watch on a bracelet for a while and as you don’t see 62MAS on bracelets much, I thought I’d take a couple of finishing snaps with it so fitted: