Meanwhile, on another bench....

Meanwhile, on another bench....

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Variomatic

Original Poster:

2,392 posts

160 months

Wednesday 27th April 2016
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Was going to add this to Eddie's bench thread but he's posting such goodness on there that I decided not to interfere smile

This was something a little unusual that came up courtesy of a fellow PHer, a Chinese tourbillon movement in a BHI watch. In some ways reassembly of these is actually easier than most ordinary movements because you have all-round access to the escapement and can move it as needed to see what you're doing.

Unusually, the movement is assembled into the back plate and the front is then put on last. I've skipped over the boring stuff (keyless / winding works) and started taking pics as the main train goes in.

First, set the third wheel:



Then follow that with the empty carriage.

If you look underneath the gold bits, you'll see a steel coloured gear. The carriage is mounted in a bearing in the centre of that wheel and the wheel is screwed to the back plate to keep it stationary while the carriage rotates in the bearing.

The carriage has a pinion (small gear) fitted below the bearing, which the third wheel drives, causing the carriage to rotate.

If you look closely near the top edge of that wheel you'll see that it also has a jewelled hole set in it which acts as the top bearing for the third wheel:



At this point we can check the carriage for freedom by turning the third wheel (see first few seconds of the video linked below).

Next come the escape wheel and the pallets. The pinion of the escape wheel meshes with the stationary gear mentioned earlier so that, as the carriage rotates, it's turned by "rolling" round the outside of that wheel:



The lump of Rodico (non-sticky blu-tac) in the last photo is just there to stop the carriage rotating as the next parts are placed - it moves at the slightest touch otherwise.

The top pivots of the escape wheel and pallets are held by a single "T" shaped bridge held by two screws. Then the balance is fitted over the top of that bridge and held with a circular bridge of its own:





At this point, applying light pressure as before to the third wheel should set the carriage in motion, controlled by the escapement (again, in the video).

Once that's good, the rest of the train consists of the centre wheel and the mainspring barrel. They simply drop into place:



The front plate's fitted, the remaining pivots oiled (the carriage is done as you assemble it), and some wind applied. All being well, you have a running movement.

https://www.facebook.com/AngleseyWatchesAndClocks/...

Paul Drawmer

4,865 posts

266 months

Thursday 28th April 2016
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I like that Joe, thanks for posting.

Spice_Weasel

2,286 posts

252 months

Thursday 28th April 2016
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NeMiSiS said:
Along with Edwards post this too could be one of my favourite visits, I hope you have the time and patience to photograph and document certain jobs and keep the post running.
That's a good idea and I have a suggestion. I mentioned to Joe that I need to send my IWC chrono to him to fix as I absent-mindedly changed the date without checking where the movement was in relation to midnight. It's now changing the date at midnight but the day approx 12 hours later. The movement is IWC's tweaked version of the 7750 ebauche so may be of interest to those with similar movements in their watches.

apotek

647 posts

184 months

Thursday 28th April 2016
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Should be arriving home today,looking forward to it. Great post Joe and thanks again.

Variomatic

Original Poster:

2,392 posts

160 months

Thursday 28th April 2016
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Spice_Weasel said:
[...] The movement is IWC's tweaked version of the 7750 ebauche so may be of interest to those with similar movements in their watches.
Funny you should mention that, this is what happens to an Omega tweaked 7750 (central date hand, day & month, 24 hour + running seconds @ 9) when you undo all the screws eekwink




Not sure I'll have time to take more photos of this one as it goes back together because I'm pretty well flat out at the moment. Hopefully when yours comes this way I'll have a little more time smile

apotek

647 posts

184 months

Thursday 28th April 2016
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Out for lunch for 37th wedding anniversary wristshot

Troubleatmill

10,210 posts

158 months

Thursday 28th April 2016
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Lovely.

Thank you for posting it up.

glazbagun

14,259 posts

196 months

Thursday 28th April 2016
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I've never had a chance to test one of these on a timing machine, but have often wondered- how did you find the carriage was poise wise? Do you get a wave going on or do they have it spot on?

Variomatic

Original Poster:

2,392 posts

160 months

Thursday 28th April 2016
quotequote all
glazbagun said:
I've never had a chance to test one of these on a timing machine, but have often wondered- how did you find the carriage was poise wise? Do you get a wave going on or do they have it spot on?
The carriage seems pretty well poised tested in its own bearing, so any out of poise is less than the friction of the bearing itself and likely to have little effect in use.

There is a bit of a wave in vertical positions, not much horizontally, so the tourbillon seems to be doing what it says on the tin and not introducing variations of its own from friction or meshing variations.

The trace was ok but not the cleanest I've ever seen (possibly noise from the carriage fooling the timing machine?), amplitude was pretty constant but a bit lower than you'd normally expect - around 250 deg horizontal and 230 - 240 vertical (fully wound).

Then again, this is sold for a twentieth or so of the price of starting Swiss versions and had the feel of something that could be tuned to perform a lot better if you wanted to put in the time to do so.

It's the first Chinese one I've had the pleasure of handling and, overall, it was a pleasure - the fit is a lot better than the finish and there was none of the "wing and a prayer" feeling you can get assembling some Chinese movements!

Edited by Variomatic on Thursday 28th April 21:50

Variomatic

Original Poster:

2,392 posts

160 months

Monday 9th May 2016
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Another slightly unusual job today courtesy of a PHer.

This time it was one of a pair - a pocket watch for new balance staff and service and an old Avia 9kt manual wind wrist watch. Bth with sentimental value so both worthy of a little extra love. Apologies for the photo quality but it was camera phone again cos I keep forgetting to charge my other one.

As happens far too often in my life, we'll start with the money shot:



That's just to give an idea of scale for the other photos smile

Now, apart from needing servicing, this watch had a couple of fairly dire problems.

One was wear to the barrel arbor hole in the barrel bridge, which was letting the barrel lean sideways and foul the centre wheel. Didn't get a photo of the fouling but this is too much clearance on a barrel arbor:




The other problem was that the crown wheel post (also part of the barrel bridge) had been sheared off. This usually happens during amateur repair efforts because they almost always have a left-handed thread so people try to undo them the wrong way.

Normally, either of those problems would be a case of replace the bridge but, in this case, it was obsolete and a month of hunting came up with nothing. So, to the tools!

I didn't get a photo of the post broken off but, just to show that Eddie isn't the only one who can silver solder around here, this is it reattached:



Note that, because one of the winding wheels runs on this, the position is critical and the solder has to be neat if you're going to avoid binding. The underside is also critical because the outer edge of the post forms the top part of the bearing for the winding stem. Again, out of position or too much solder will cause problems:



Eddie would probably frown, but I must admit that fr this sort of job I tend to use pre-mixed solder paste because I find it a LOT easier to judge how much is needed.

So, with the post reattached, time for some good old metalwork on the arbor hole. You can buy brass bushes with a pilot hole in various outside diameters, usually used for pocket watch repairs but also a godsend in cases like this. In this case, the arbor was 1.5mm diameter and there was a small boss underneath the plate which was 2.3mm diameter, so a 2mm bush should work well:



To fit, you open the hole up until the bush is a firm press fit. Opinions are divided about whether you hen just press it in or chamfer the hole, press in and rivet into the chamfer. Personally I tend to rely on a press fit if the plate is more than 3/4 mm or so thick but will rivet below that to be sure of enough grip. This one called for riveting.

In either case, when opening the hole you have to allow for the fact that the old one has worn, and it hasn't worn evenly - they tend to wear on one side and, if you simply open the hole, the new hole will be slightly out of place.

You can use a jewelling tool to ensure the hole's in line with the bottom one but, in this sort of case I prefer to work by hand / eye because it's quicker and the tolerances aren't as close as for main train wheels.

Using a tapered, 5 sided, broach, you cut the new hole applying side pressure for the initial cut to guide the hole back to where it should be:



In this case, the boss underneath provided a good guide to that - it's surprisingly easy to tell by eye if two circles are concentric.

Once the hole's to size, the edges are slightly chamfered top and bottom, the bush pressed in, and then riveted using a staking set to fill the chamfers:



Next the top end of the bush is taken down flush with the bridge, hopefully without marking the surrounding metal too much! The pilot hole in the bush is then broached out (from both sides to allow for the taper of the broach) just like before until the barrel arbor is a snug but free fit:



We then turn our attention to the underside, and reduce the bush thickness bit by bit until the barrel fits far enough through for the ratchet wheel to fit and be screwed down tight without binding:



Once you're happy with that, it's time to refit the barrel, bridge, and ratchet wheel to the movement and check that those missing clearances have been restored:



All good to go, just need to clean everything up a little - cosmetically and to be a thousand percent (at least!) sure that none of the metal swarf finds its way into the movement - before final assembly smile

Athlon

5,000 posts

205 months

Monday 9th May 2016
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Fantastic workmanship! (Thank you.)

Variomatic

Original Poster:

2,392 posts

160 months

Monday 9th May 2016
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You're welcome smile Although really I should be thanking you for the chance to do something a little different for a change wink

glazbagun

14,259 posts

196 months

Tuesday 10th May 2016
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Variomatic said:
You're welcome smileAlthough really I should be thanking you for the chance to do something a little different for a changewink
laugh Yes, that's exactly what I think when the barrel is leaning over so far it's hitting the centre wheel, the ratchet wheel has eaten the barrel bridge and the crown wheel post has snapped clean off on a ladies movement. hehe

Of my year at watch school/uni, I was the only one to go into vintage. My friends all tell me about how lucky I am that I get to make staffs and stems, polish steel, etc. I'm looking at them thinking- "you mean I can have a salary and a pension for stripping and reassembling modern movements? And they work first time? And if you need parts, you go to the parts drawer!!!? What is this witchcraft?" cryfurious

Great thread Variomatic, I'll put up my Omega of ebay-mistakeness when I get the chance. It's a tale of a good watch ruined by a poor owner/watchmaker combo and bought by a drunken fool on a Saturday night train!

I do wonder if the Chinese/Japanese will ever get the hang of luxury marketing. They already have the ability to produce top drawer watches, but seem to be lacking the "why" more than the "how". Surely a skunkworks in Seiko with their top dial maker, etc, would pay for itself after the first watch they released?

Edited by glazbagun on Tuesday 10th May 23:47

glazbagun

14,259 posts

196 months

Wednesday 11th May 2016
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I was thinking about tourbillon levels of expensive. Seiko were very good at getting the hang of the technical challenges of watchmaking in the late 60's. But they have no JLC gyrotourbillon, or Gruebel Forsey. Citizen own a Swiss company who do high end work, but don't shout about it, and very few in the west know what a Credor is. It's a whole topic for another thread so I'll stop derailing this one. hehe

Variomatic

Original Poster:

2,392 posts

160 months

Wednesday 11th May 2016
quotequote all
Internet threads are made to be derailed wink

I suspect that part of the reason the Japanese haven't really pushed the high end of the market is that they'd be hard pressed to overcome the prejudice against most things not "Swiss Made", or at least European - much the same as us indies are forever fighting in the "dealer service only" stakes!

As for the difference between vintage and modern repairs, I'm lucky that I get to tackle both, although don't do anything like enough "making" to make it worthwhile most of the time - turning staffs etc if you only do one every couple of years is like learning fresh each time and quickly becomes unprofitable when it takes half a dozen attempts to get your hand back in! biggrin

PJ S

10,842 posts

226 months

Wednesday 11th May 2016
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^
Sorry Joe…but he started it! biggrin





Edited by PJ S on Wednesday 11th May 18:25

Variomatic

Original Poster:

2,392 posts

160 months

Wednesday 11th May 2016
quotequote all
Not a problem, and that illustrates nicely what a disservice Seiko UK are doing us by restricting their imports to Kinetics, 5's and a few starter Spring Drives!

Edited by Variomatic on Wednesday 11th May 12:21

glazbagun

14,259 posts

196 months

Wednesday 11th May 2016
quotequote all
I genuinely didn't know they had a tourbillon! The previous best watch I'd seen from them was the (much more tasteful!) ceramic dialed Eichi.

http://watchesbysjx.blogspot.co.uk/2015/07/face-of...

mistergrumpy

76 posts

158 months

Tuesday 26th July 2016
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Are there any more updates to this thread. I love this kind of stuff.

mistergrumpy

76 posts

158 months

Tuesday 26th July 2016
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Ah. Can't complain at that then.