20th c escapement Revue 31 (JW Benson) Overhaul (running fast)

[svenedin]

I am planning my next overhaul job. As a hobbyist these overhauls take me a long time and I like to plan jobs. I have learned to try to diagnose faults before I have the watch in pieces!

I do not know anything about the history of this watch. I bought it at auction some years ago. It has sat unused because I will not use watches that have not had a service.

The movement is Swiss, a Revue 31 with a cut bi-metallic balance and blue steel Breguet overcoil hairspring. 17 jewel gilded movement of good quality with jewels in screwed in chatons. Case of 9ct gold, Dennison made with UK hallmarks (Birmingham) for 1930.

The watch runs but on the timing machine the amplitude is not great (240 degrees) which does not surprise me (very dirty movement). The problem is the watch is running very fast: +120 seconds with the regulator hard over to slow.

A preliminary inspection shows that the hairspring seems in good order. There are no touching coils, it is not bent or damaged, there is no touching of the hairspring on anything. I cannot see any "spare" hairspring sticking out from the balance cock stud (but the watch is still assembled at present so it is hard to see). I can see that the regulator index pins are bent out of parallel and splayed in an odd way. The hairspring is against one of the pins at rest.

The other thing I have noticed is that there are 2 empty balance screw holes 180 degrees apart.

So my question at this stage, prior to commencing work, is what is likely to be causing the watch to gain 2 minutes a day? Could it be the missing balance screws making the balance wheel too light? I am thinking that with the additional screws the centre of mass of the balance will be moved outwards and it will oscillate slower but would the change be excessive? I have a scrap movement of the same calibre (broken balance). The balance wheel on the scrap movement has all screw holes occupied.

 

[gmorse]

Hi Stephen,

Before wondering about remedies and swapping things about, the first step should always be to dismantle, inspect and thoroughly clean, only then can you move on to diagnose the problem, which remarkably often, has by that stage disappeared. Low amplitude in a lever can often result in a gaining rate. Empty holes in the balance rim don't necessarily mean that screws are missing, (unless they're at the timing screw positions), they're there to allow relocation of the compensation screws if necessary.

Regards,

Graham

 

[svenedin]

Hi Stephen,

Before wondering about remedies and swapping things about, the first step should always be to dismantle, inspect and thoroughly clean, only then can you move on to diagnose the problem, which remarkably often, has by that stage disappeared. Low amplitude in a lever can often result in a gaining rate. Empty holes in the balance rim don't necessarily mean that screws are missing, (unless they're at the timing screw positions), they're there to allow relocation of the compensation screws if necessary.

Regards,

Graham

Thanks Graham. Yes I agree but I do like to do an initial investigation because at my level of skill I want to be sure I haven’t made something worse!

 

[Skutt50]

The hairspring is against one of the pins at rest.

As Graham suggested a service is where to start. The gain of two minutes may well be explained by the hairspring resting against one of the banking pins, but start with a service and see what happens.

 

[svenedin]

As Graham suggested a service is where to start. The gain of two minutes may well be explained by the hairspring resting against one of the banking pins, but start with a service and see what happens.

Will do and I’ll update the thread as I go along. It’s a nice watch and I look forward to using it.

 

[svenedin]

I have started the overhaul on this watch. It is in pieces and I will clean everything tomorrow. I. have noticed a few things as I took the watch apart:

1) The hour hand was pushed so far down onto the dial that it was impossible to get a lever or even a razor blade underneath it. I decided to take the dial off (very carefully) with the hour hand still attached. The dial came off with the hour wheel still attached underneath. I usually take the dial off with the sub-seconds hand still attached anyway.

2) There was no dial washer and the hour wheel looks a bit odd. It seems worn.

3) Most of the screws were quite difficult to remove but I was patient to avoid amateur slips and scratches. It seemed to be old oil that was gumming up the screws.

4) The mainspring barrel did not want to let go of the barrel bridge. It looks like someone has had a go at closing the hole in the bridge with a punch. In the photo the click spring is still in situ because it did not want to come out. I expect it to come out in the ultrasonic and hopefully not before!

5) The index pins in the regulator are at an odd angle and they also seem very much fatter than the index pins in my identical scrap movement.

6) There was some matte looking substance on the edges of the dial. Perhaps glue for the watch glass. I have put the dial in some denture cleaner.

7) The hands are a bit rusty but my scrap movement actually has perfect hands. I may swap them and then use the bad hands to practice bluing.

8) The mainspring is clearly set and strangely is 0.19 thickness which is the thickness of the new spring I have. I was a little concerned that I could not get the 0.18 thickness specified.

9) The watch is very out of beat and the impulse pin is miles off.

 

[svenedin]

Everything clean and ready for inspection and assembly tomorrow.

 

[svenedin]

Well no surprise here......I have found a problem. A broken jewel on the escape wheel bridge. I have nothing suitable as a donor so it looks like I am going to have to put the watch back together and find a kindly watchmaker who will do this job for me. In the photo it looks like there is another damaged jewel but it is a trick of the light.

 

[gmorse]

Hi Stephen,

These jewels are probably rubbed in to their settings, and obtaining a replacement jewel for this centre arbor setting may present a problem, as this type is no longer made. The ideal option would be a part from a donor movement.

If that option doesn't prove possible, a modern friction fit jewel fitted into a new setting to match the OD and fit in the plate would be necessary. The availability of these larger Seitz jewels is reducing to an increasing extent, with the number of sizes being listed as 'discontinued' growing. If a jewel with the correct ID is available there's still a problem with the modern jewels usually having a markedly darker colour than the originals.

Regards,

Graham

 

[svenedin]

Hi Stephen,

These jewels are probably rubbed in to their settings, and obtaining a replacement jewel for this centre arbor setting may present a problem, as this type is no longer made. The ideal option would be a part from a donor movement.

If that option doesn't prove possible, a modern friction fit jewel fitted into a new setting to match the OD and fit in the plate would be necessary. The availability of these larger Seitz jewels is reducing to an increasing extent, with the number of sizes being listed as 'discontinued' growing. If a jewel with the correct ID is available there's still a problem with the modern jewels usually having a markedly darker colour than the originals.

Regards,

Graham

Hello Graham. Thanks for your reply. It's the centre wheel of course!. How daft of me first thing in the morning. It's a screwed in jewel. Are these just as difficult to replace? A donor will be hard to find as the screwed in type jewels only seem to have been used in the higher-end Benson movements. Most movements of this type have rubbed in jewels. Of course finding any knackered movement of similar size with screwed in jewels would not be difficult but I would have no idea whether the jewels would prove useful.

Edit: I have found a potential donor at low cost. A Vertex Revue 31 loose movement with a broken staff and the same screwed in jewels. I will not know whether the centre wheel jewel is in good condition until I receive it.

Graham are you saying that the screws are just for show and the jewels are in fact rubbed in?

 

[gmorse]

Hi Stephen,

Graham are you saying that the screws are just for show and the jewels are in fact rubbed in?

No, I think these jewels are rubbed in to the settings, which are then held in the plate with screws. This means that in the absence of an exact replacement jewel in its setting, (aka 'chaton'), one repair option is to fit a Seitz friction fit jewel in a new setting made to fit the jewel's OD and also the plate/cock/bridge. This would retain as much as possible of the original appearance, apart from the jewel colour. There are a few people who can make rubbed-in jewels, but that would be a rather expensive solution.

A picture of the underside of that cock would be useful to verify that the jewels are in settings and not rubbed-in directly in the cock.



Regards,

Graham

 

[Bernhard J.]

You both will beat me, but I think that I would leave this split center wheel jewel alone and merely avoid looking at it. If the inner diameter of the split jewel does not have an evident edge (likely not), I would not see significant risks, even if the watch is used more or less often. If not the center wheel, I would tend to replacement as well.

I wonder anyway about split jewels, I have not encountered one in decades. How does one manage to damage a jewel other than by raw force?

Cheers, Bernhard

 

[svenedin]

You both will beat me, but I think that I would leave this split center wheel jewel alone and merely avoid looking at it. If the inner diameter of the split jewel does not have an evident edge (likely not), I would not see significant risks, even if the watch is used more or less often. If not the center wheel, I would tend to replacement as well.

I wonder anyway about split jewels, I have not encountered one in decades. How does one manage to damage a jewel other than by raw force?

Cheers, Bernhard

Hello Bernhard I did wonder how the jewel was originally damaged. Clumsy fitting of the bridge? Could it be damaged when fitting the cannon pinion?

This watch will probably get used rather often as I am fond of it!

 

[svenedin]

Hi Stephen,


No, I think these jewels are rubbed in to the settings, which are then held in the plate with screws. This means that in the absence of an exact replacement jewel in its setting, (aka 'chaton'), one repair option is to fit a Seitz friction fit jewel in a new setting made to fit the jewel's OD and also the plate/cock/bridge. This would retain as much as possible of the original appearance, apart from the jewel colour. There are a few people who can make rubbed-in jewels, but that would be a rather expensive solution.

A picture of the underside of that cock would be useful to verify that the jewels are in settings and not rubbed-in directly in the cock.

View attachment 714010 View attachment 714011

Regards,

Graham

Hello Graham. Photo as requested.

 

[gmorse]

Hi Stephen,

Thanks for the picture, which appears to show two things; one, that the jewels are in separate settings, and two, that the damage to the jewel is more serious than a simple crack, and potentially damaging to the pivot. Have you looked closely at the pivot which runs in that jewel?

I suspect that it may have been damaged in an attempt to remove the cannon pinion, but careless fitting of the cock or the cannon pinion are equally possible. The cracks are consistent with excess sideways pressure, perhaps with the other end of the arbor unsupported.

If the settings are subsequently found to be false, I would be very surprised, in view of Benson's reputation.

Regards,

Graham

 

[Bernhard J.]

Well, that indeed is serious damage, wow! Forget what I said previously

 

[svenedin]

Hi Stephen,

Thanks for the picture, which appears to show two things; one, that the jewels are in separate settings, and two, that the damage to the jewel is more serious than a simple crack, and potentially damaging to the pivot. Have you looked closely at the pivot which runs in that jewel?

I suspect that it may have been damaged in an attempt to remove the cannon pinion, but careless fitting of the cock or the cannon pinion are equally possible. The cracks are consistent with excess sideways pressure, perhaps with the other end of the arbor unsupported.

If the settings are subsequently found to be false, I would be very surprised, in view of Benson's reputation.

Regards,

Graham

Hello Graham. Yes I looked at the pivot as soon as I found the cracked jewel. The best I can do is a 10x loupe in good light. The bit of the pivot that sticks out beyond the jewel hole looks highly polished whereas the part that sit in the hole looks matte. It's not scored though. In a way I am quite relieved to see that on the pivot because it looks like it ran for a while with a broken jewel. I would not be happy if I had cracked the jewel! I removed the cannon pinion by putting a pin vice around it and pulling which is what I normally do. That's not wrong is it? I know hand levers can also be used.

How easy or difficult is it to swap out a jewel in a setting?

 

[svenedin]

Another thought. Is it possible to crack the centre jewel by fitting the hands with excessive force? I noticed when I took the watch apart that the hour hand was pressed right against the dial. Maybe the minute hand was similarly fitted.

 

[Bernhard J.]

Another thought. Is it possible to crack the centre jewel by fitting the hands with excessive force?

Well, if someone uses a two pounds hammer for doing this ....

 

[svenedin]

It's running but of course I won't run it for long with that cracked jewel.

Already I met challenges I met for the first time:

1) I had not anticipated quite how difficult it is to get the stud back in the balance cock with a Breguet overcoil. I tried it with the balance cock upside down on the bench but I could not see what I was doing through the hairspring on top. I then put the balance and cock in the watch and worked from the side and this did work. Scared me though!

2) It is hard to screw the top cap setting back on with the regulator just sitting on top of the balance cock.

3) It is tricky to get the hairspring between the index pins of the regulator

4) I have never worked on a negative set watch before and I do not have bench keys. Keyless works somewhat different.

 

[gmorse]

Hi Stephen,

How easy or difficult is it to swap out a jewel in a setting?

If you're lucky enough to find a jewel in its setting from a donor movement, all you need is a screwdriver and a piece of pegwood, (to press out the old setting). If not, and you have to go the route I described earlier in post #11, that involves a lathe to make the setting and a jewelling press to fit the jewel into it. It's unlikely that you could modify the old setting to take a friction jewel securely.

Some of the challenging things you mention can be eased if you're working closer to eye level; you'll see many professionals sitting on quite low stools, with high benches or some sort of auxiliary platform to bring the work up higher and nearer the eye.

Regards,

Graham

 

[svenedin]

Hi Stephen,


If you're lucky enough to find a jewel in its setting from a donor movement, all you need is a screwdriver and a piece of pegwood, (to press out the old setting). If not, and you have to go the route I described earlier in post #11, that involves a lathe to make the setting and a jewelling press to fit the jewel into it. It's unlikely that you could modify the old setting to take a friction jewel securely.

Some of the challenging things you mention can be eased if you're working closer to eye level; you'll see many professionals sitting on quite low stools, with high benches or some sort of auxiliary platform to bring the work up higher and nearer the eye.

Regards,

Graham

Thank you Graham. Yes! I knelt on the floor on a cushion so I could look at eye-level across the movement.

That is very good news with regard to the jewels because I looked again and the third wheel jewel is cracked as well. I saw it on my photo rather than actually in front of me and then went back and looked again.

The donor movement will arrive in a few days. It's another Revue 31 with what appear to be exactly the same screwed in jewels. Well not exactly the same, hopefully not broken! It was cheap because it has a broken staff, missing regulator etc but has everything I need I hope. In fact it would have been a better movement than mine originally that donor, 21 jewels, micro-regulator etc.

When the donor arrives I'll take the bridge off and measure whether the settings are the same size. If they are then I will try the pivots from my movement in them. If that goes well I will clean every thing up and prepare for the transplant.....

 

[svenedin]

Whilst I am waiting for the donor movement to raid for jewels I thought I would try to sort out some other problems.

I noticed before I took the watch apart that the hand setting felt awful. It was stiff, jumpy and grinding. Really bad. I hoped it was just all gummed up but unfortunately not. I am not sure at the moment exactly what is wrong. What I have noticed so far is that in hand setting (the default for this negative set watch) the first intermediate wheel does not seem to engage well with the sliding clutch. I examined both closely and can see no damage. I made sure the parts were installed correctly, I tried the first intermediate wheel both ways up (made no difference). On other movements the first intermediate wheel is definitely the right or wrong way up but here it is just a plain gear. I put some pressure on the stem to bring it to winding position in case the first intermediate wheel was not fully down on its post. Still the winding action feels horrible. Then I noticed that the minute wheel jumps about on its post and has clearly done that for a long time as it is scored on top and worn. I had previously noticed the same on the top of the hour wheel. I have a scrap movement with intact keyless/motion work which works smoothly and will study this to see if can work out what is wrong with the movement I am working on.

 

[svenedin]

Keyless work issue is fixed. Close examination revealed the teeth of the sliding clutch that engage with the intermediate wheel to be worn and rounded. I replaced both the sliding clutch and the intermediate wheel from my parts movement and everything is fine now. If I had a microscope and the skills perhaps I could have repaired rather than replaced but for now the worn parts can go back in the parts movement. If this watch ever works again it is going to need complete disassembly again and another bath!

I had a surprise as I let the power down on my movement; the upper crown wheel unscrewed itself and came flying off. Luckily there wasn't much power. Looking at the parts movement it was not the correct screw (but it was reverse thread as it should be). I am beginning to think that the removing the balance and pallets method of letting down power is safer. I had to do that anyway on the parts movement as there's no stem.

 

[svenedin]

For my own education and practice I put the worn parts into the parts watch and it now has exactly the same issue so it was wear for sure. I am learning that wear and damage that is barely perceptible to me, through my ignorance and inexperience, can have drastic effects on the functioning of a watch. It did occur to me that if anyone gets hold of any of my loose movements, that look intact, after I am dead they are in for a shock because they are full of worn out parts. I intend to be fully worn out too before I call it a day!

 

[svenedin]

Another job I did was to correct the very large beat error at least visually. I noticed there is a “sighting hole” in the movement that allows the roller table to be viewed from the side as well as the usual method of looking through the banking pins (or pallet bridge in this case). Hopefully it will be at least ballpark in beat. I corrected the splayed out bent index pins on the regulator to match an unmolested regulator on the parts movement (also over coil)

 

[roughbarked]

Keyless work issue is fixed. Close examination revealed the teeth of the sliding clutch that engage with the intermediate wheel to be worn and rounded. I replaced both the sliding clutch and the intermediate wheel from my parts movement and everything is fine now. If I had a microscope and the skills perhaps I could have repaired rather than replaced but for now the worn parts can go back in the parts movement. If this watch ever works again it is going to need complete disassembly again and another bath!

I had a surprise as I let the power down on my movement; the upper crown wheel unscrewed itself and came flying off. Luckily there wasn't much power. Looking at the parts movement it was not the correct screw (but it was reverse thread as it should be). I am beginning to think that the removing the balance and pallets method of letting down power is safer. I had to do that anyway on the parts movement as there's no stem.

If you are going to take the pallets out and let the train run down, you should have a bit of pegwood or something at hand to slow it down as it runs. Spinning the wheels quickly can lead to rapidly damaging existing pivots.

 

[svenedin]

If you are going to take the pallets out and let the train run down, you should have a bit of pegwood or something at hand to slow it down as it runs. Spinning the wheels quickly can lead to rapidly damaging existing pivots.

Yes. With the scrap movement I just used my finger on the centre wheel but peg wood or my plastic pusher downer on a clean movement.

 

[svenedin]

The donor movement arrived to harvest the required jewels. I was excited that a fix might be in reach. The jewels are darker in colour but I was not unduly concerned to get the watch working.

I cleaned up the donor bridge and to my great dismay it also has a cracked centre wheel jewel!!! It was so incredibly lucky to find donor jewels of the right type but it was not to be. I will have to put the watch back together and sit and wait until I can find another donor, if ever. It feels like a complete waste of time.....

 

[svenedin]

I put the movement back together in a rather deflated mood just so that nothing gets lost. As I had the movement in just the right light I noticed something else. To add insult to injury the centre wheel jewel on the dial side is cracked too. I did not notice that before. So the movement has 3x broken jewels.

 

[roughbarked]

With no damage to dial or case, it is beginning to sound like some ham handed induvidual really did bang on the canon with a big hammer. More likely levered it. Which would do the sideways pressure Graham mentioned.

 

[gmorse]

Hi Stephen,

That's a real shame. Too much arbor and not enough jewel!

Regards,

Graham

 

[svenedin]

Graham and Roughbarked,

Yes. There is no doubt in my mind that somebody has been in the watch before who had some idea of what to do but not enough of an idea. The evidence is: 1) glue on the dial from gluing in a crystal with the bezel on the watch 2) Broken centre wheel jewels front and back AND broken 3rd wheel jewel on the bridge 3) Regulator pins bent at an absurd angle because they knew the hairspring should go through the regulator but not how to get it there. 4) Hour hand rammed down onto dial 5) awful keyless/motion work 6) No dial washer 7) Watch so out of beat (if it would ever run again) that the impulse jewel was somewhere in Australia 8) and a LOT of oil.......

I have a horrible recollection that the chap I bought the watch from years ago said it was "never the same" after the last "watchmaker serviced it" !!!!!!

 

[svenedin]

So now I have to decide what to do with this watch:

A) Scrap it entirely, case and all and call it an unfortunate purchase? I don't want to do that. The case it far too good for scrapping

B) Wait until I can find another donor movement for the 2 bridge jewels and then ask a watchmaker to fit a new jewel for the centre wheel dial side jewel? This is definitely an option

C) BUT.....what if the donor movement that comes up is far too good to be a donor? What if it is a JW Benson branded Revue 31 hunter 17 jewel that turns up in excellent condition? It would be very tempting to fit the better identical movement in such circumstances...........hmmm

 

[svenedin]

I searched for another suitable donor of jewels but I could not find another Revue 31 with 17 jewels. Eventually after looked through hundreds and hundreds of listings for “pocket watch movement” I found a Revue 30 branded “Syren”. I took a punt at £10 that the jewels might be the right size. Long shot. We’ll see in due course!

 

[roughbarked]

There is a height difference between the two..

 

[svenedin]

There is a height difference between the two..

OK but does that affect the jewel sizes? If it doesn’t work out at least I’ve got some more screws and springs to add to my junk.

 

[roughbarked]

Probably shouldn't affect the jewel sizes but does the one you ordered have the same style of jewel fittings?

 

[svenedin]

Probably shouldn't affect the jewel sizes but does the one you ordered have the same style of jewel fittings?

Yes. Jewels in chatons, screwed in. The settings look identical but they may not be the right size. They’re rare in these movements. Vast majority are only 15 jewel movements and even when I find a 17 they’re rubbed in type. I’m just hoping there’s interchangeability between Revue 30 and 31. They’re both 19 lignes so for the sake of £10 it seemed a reasonable gamble.

 

[roughbarked]

Should come close then. Best of luck.

 

[svenedin]

Should come close then. Best of luck.

Thank you. I’ll need the luck. You’d think that a watch in a gold case would be a warning signal to a complete novice to stay away. I know that the watch was the seller’s grandfather’s watch. Now of course I am hardly that experienced myself but I hope I know what to stay well clear of. Having said that, if I’d had any sense I’d have a run a mile when offered this watch!!!!!

 

[svenedin]

Whilst I am waiting for suitable replacement jewels to turn up I thought I would look at the pivots.

I have noticed that my watch has different shaped pivots to the scrap movement of the same type that I have. My watch has tapered pivots but the scrap watch seems to have pivots that are much more square. Is this wear or design? I am wondering whether in fact the jewels from the scrap watch would ever have been suitable given this difference. Having said that, some parts, wheels for instance, are still available for the Revue 31 new and there are no variants, they are all apparently the same so I am thinking this is wear. Apologies for the photos but I took the photos through a loupe (which is really difficult)

My watch (2nd wheel pivot)



Scrap movement 2nd wheel pivot

 

[gmorse]

Hi Stephen,

I have noticed that my watch has different shaped pivots to the scrap movement of the same type that I have. My watch has tapered pivots but the scrap watch seems to have pivots that are much more square. Is this wear or design?

Those pivots on your watch don't look at all healthy. They look very short and thin, and certainly shouldn't be tapered; no watch pivots should be, at least on their acting surfaces. Are you able to see whether there's any side-shake on those?

Regards,

Graham

 

[svenedin]

I will check for side shake and end shake but I suspect the pivots are kaput. The pivots seem long enough after the shoulder, when compared to the scrap watch but the tapered ends are not normal at all.

I wonder whether the watch had a mainspring break at some point which might account for some of the damage but there's definitely bodger damage in the watch too. Damage is on top of very significant wear I think. The only wheel I can actually test is the second wheel because the third wheel and centre wheel have broken jewels. I can if I want replace the whole wheel train from the scrap movement as it looks in much better shape but that's dependent on sorting the jewels first. I am wondering whether I am going too far with this watch to the point there is not much left from the original watch. It is of course a mass produced watch where the parts were intended to be replaceable.

 

[gmorse]

Hi Stephen,

I am wondering whether I am going too far with this watch to the point there is not much left from the original watch.

You have some way to go before you get to 'Trigger's broom'!

Regards,

Graham

 

[svenedin]

Hi Stephen,


You have some way to go before you get to 'Trigger's broom'!

Regards,

Graham

 

[svenedin]

Donor movements arrived. I managed to find 2x Revue 30 movements with screwed in jewels. Very glad I did get 2 movements because the first one has yet another broken centre wheel jewel and the second a broken 3rd wheel jewel so between them I can get the 2x jewels I need.

The new jewels fit the holes in the plates and the pivots. Even better they are the same colour.

Chaton screws are seized on the 3rd wheel jewel I need to harvest so that bridge is having a soak in penetrating oil. I have too much of a shake at the moment to get the chaton screws back in on the centre wheel jewel I have swapped.

So some progress and just maybe this watch will actually work one day! Of course it will still need the broken dial side centre wheel jewel replaced but I will have to ask a watchmaker to do that for me.

 

[Skutt50]

Chaton screws are seized on the 3rd wheel jewel I need to harvest so that bridge is having a soak in penetrating oil.

Congratulations.

If the penetrating oil does not do the job, alum will.....

 

[svenedin]

Congratulations.

If the penetrating oil does not do the job, alum will.....

Thanks for reminding me about Alum. The jewel settings look like they may be copper or a copper alloy (I have seen them in gold in some movements). Will the Alum hurt the jewel settings?

 

[svenedin]

I got the chaton screws out from the donor but then as I tightened them down having swapped a jewel the head broke off one so I will have to resort to alum. I actually have some at home. I will have to take everything out of the bridge except the snapped off screw.