Hamilton 950 L continued... to celebrate my 100th blog post :)
by, 02-23-2017 at 06:38 AM (9161 Views)
I was wondering... what to chose for my 100th post.
Obviously it should be something cool and I wish I could just save the number for some other time and just proceed to 101.
However in my collection I still had a pretty cool watch awaiting some more attention.
As you might remember I bought this watch in quite dreadful technical condition, installed a grade 992 pallet fork and a new hairspring and left it be. So today, I'll show you the 950L in details, let's go !
Disassembled into pieces. The watch has a motor barrel and the raychet wheel seems to be attahced tight to the tube (don't know the word) that goes into the barrel and winds the spring. Normally most makers would use a triangle shaped design that can be disassebled, but this appears to be joined tight. Telling by the ammount of old oil someone poured under the wheel (most of which would now be under the screw on cap), I'm not the first one stuck on this design...
The barrel has a thin arbor with pivots for two jewelled bearings.
The idea of a motor barrel is that it acts as properly jewelled 1st gear, but since during wind-up you still pull the inner end of the spring, it still needs a safety pinion on 2nd gear. Safety barrel can by of similar desing, but there you turn the entire barrel and the inner end pulls the 1st gear arbor. Some makers used motor, some safety and some both barrel designs in their watches...
Among the parts that also would need explanation is the keyless works lock (middle right pic above).
For some rason it was left in the watch, despite it's completely useless and it does not do anything. In the pendant set veriosn this would lock the keyless works in the winding position when out of case.
It's here, because this watch comes from a run planned to be pendant set, but finished as lever set.
Some have the additional parts, some not.
Assembling the barrel bridge complete.
It might seem difficult that you have to (not being even able to see) insert the center tube in the barrel and 'fish' the mainspring end with the tube's tooth, but this one actually prooves easier done than said, so to say.
In motor barrel desing it'strue the screw down cap might NOT be removed at all, but if you remove it, you'll have more space to manouver the barrel and you won't risk cracking the jewel as well. Not to mention more thorough cleaning.
Assembling the keyless works:
The intersetting gears need to be filed side down.
And now the train...
The underside might not look impressive, but the top side of the gears is superb...
And so is the steel escape wheel. It's finished wonderfully and surely the 950 is among the best finished watch I've worked on so far, maybe equaled by Waltham's Riverside Maximus and Elgin 'lace doily' grades (which were not RR grades, though - I'm mentioning the finish quality)...
I was asked if the winding bridge number matches the rest - it does.
The pallet fork I got a bit stuck on...
It's a grade 992 pallet fork, as the original one was broken when I got the watch, and it fits nicely, but...
The 'but' in this case was that once it would moove smoothly and once it would get gummy in place.
Also, although it seemed to be working well before oiling, with new oils in the movement, when I 'tried' the escapement action, the fork's motion was too slow and it was usually late to lock the escape wheel, bouncing off the impulse surface.
Since there was no endshake, so I thought maybe the staff was of very exact length.
But more trouble came when I took off the top side cap. The fork would then click in the bearing and stay.
Looking at the pivot - there was some wear and corrosion, so maybe it was rust, maybe it was a bit 'mushroomed' - I just polished the pivot, slightly polished the fork itself (though I have no means to nicely mirror-polish parts yet and there are still plenty of micro-scratches seen under certain angles)
After that, the escapement started working just fine.
And the balance...
Last time when I left the watch - it was about half an hour a day slow.
Since I worked so hard on the escapement, leaving the watch not timed would be a disappointment.
The red arrow points a hairspring problem - two touching coils, easy to correct.
Since I used up most of my gold screws for Adams&Perry project, I did not have many screws to chose from and I found just one pair that looked like good replacement for a pair of original, heavier screws.
So I replaced a pair of screws with lighter ones, checked the poise which was dreadful (interestingly, the very apparent heavy spot was on one of the original screws), so I added balance screw washers on the light side and got it (very roughly) poised.
Since I installed lighter screws and it was just 30 minutes a day, I unscrewed the mean-time screws, but had to screw them somewhat back in, during final timing.
The remaining assembling process pictured (done before the timing, of course) and...
That's not bad timing I'd say
Obviously, I timed it in one position and no doubt this will have quite some positional devaition*, but after 40 minutes it's accurate and as I write, it's also accurate after 2 hours. Good enough for me, I won'r recreate the long gone factory RR adjustment, not skills and no tools for that. And no boxes of gold balance screws as well...
Cased, timed, ready to go back on it's shelf.
It's a beautiful watch and I'm glad I finally made it keep time again.
I always say a collectable watch can be not accurate, but 30 minutes a day in a good looking RR watch... a disgrace...
I hope you enjoyed the post... it's my 100th after all !!!
Couldn't resist to check...
It seems that tghis wast is about timed dial up and down, and has from -5 to -25 sec/day in vertical positions. Not very bad...