Anyone got any ideas on how to get a broken screw out of a first wheel by the barrel arbor please?

I understand the standard method when the screw has broken inside the barrel arbor is to dismantle the watch and replace the whole barrel. However, a few years ago, I watched (not closely enough) a repairer on 47th St proudly tease one out with an ordinary screwdriver as a challenge in a minute or so, obviously without dismantling anything!

Is there supposed to be some way of tapping it in place to loosen it so that you can get a bit of purchase on the broken rump of the screw please?

The repairer, who has since disappeared off the face of the earth (actually with a watch of mine of no particular value) attended some watch-maker's school in South Africa, possibly where they teach this sort of thing?

 

When asking a question like this, it helps us help you if you actually give us some information, like what caliber you (or your watchmaker) are working on.

I'm assuming we are talking about a Speedmaster here, so the screws that hold the friction spring in place on the barrel lid? If so, what specific movement is it - 321, 861, 1861? First off, if it is a Speedmaster, you can't even see the barrel (except a small portion of the OD) without disassembling the movement.

When removing a broken screw there are a few methods available, and these are things I do pretty much in the order I would try them:

1 - If you are very lucky, and the screw is not jammed in the tapped hole, sometimes you can get it out just using tweezers, an old oiler, or a screwdriver. Sometimes tapping on the screw will help loosen it. I'll be honest it's not all that often that this works - I think the guy you saw just got lucky, as there is no special trick for this really.

So assuming the screw I jammed in the tapped hole and won't turn easily:

2 - Broken screw extractor - Bergeon makes one, but I typically find the tips of this unit are far too big for most broken screws I encounter, although I did use it yesterday to remove a broken casing screw from an ETA 6498 powered watch (Swiss Army).

3 - If the screw is not broken off completely flush with the plate or surface it's jammed in, but there isn't enough material sticking up to get ahold of, I will sometimes use a screw slot file to file a slot in what's left of the screw, and then use a screwdriver to turn it out. You must be careful not to damage the plate or surface when doing this though, so filing skills are needed.

4 - Alum. Dissolve alum crystals in a small glass of warm water, enough that just a few crystals can't dissolve - you want a strong solution. Then take the part (must not be ferrous steel) and place it in the solution, and leave it for a few hours. Periodically remove it from the solution, and remove any black residue that has built up on the screw you are trying to dissolve. Usually overnight the screw will dissolve completely - warming the solution on a heating plate will accelerate the action. Alum can usually be purchased in the spice aisle of your local grocer. Again if the part or plate you are submerging is steel, it will also dissolve - fortunately most plates and some parts (like the barrel drum and cover) are made of brass. If the plate has some metal parts on it that can't be removed, I either hang the plate using some brass wire so that only the portion with the broken screw is in the solution, or a coat the steel portions with Fomblin grease to keep the solution from getting on steel parts.

5 - Last resort is to replace the part, and in this case (Speedmaster) it would be either the barrel complete, or possibly just the barrel lid, which is way less money.

Cheers, Al

 

Thank you for your very complete reply, indicating that this is a big deal and that there is unlikely to be any quick fix. Not sure why you thought it was a Speedmaster, - my question was generic as is the problem. I am not sure that the screw body which stayed in there when the head broke off is actually stuck, as opposed to being simply broken: But before I try to sink it in a bath of corrosive liquid which i will (in my case) have to hope doesn't risk making the whole problem worse by damaging major parts of the watch, I would like to try a simple ultrasound bath to somehow either extrude the screw or loosen it a bit so that some other method lets me get it out in the way i sorta saw it being unscrewed.

 

The reason I thought this was a Speedmaster (other than being posted on an Omega forum) is because you said that there is a screw in the barrel - not many watches have screws in the barrel mate...



As I mentioned, telling us what you are working on (you still have not done so) will help to answer your questions. If I knew what you were working on I could advise you if the part is readily available, possibly very cheap, or if it's hard to find so you have no choice. I'm trying but you are not helping me much!

I take it you are not a watchmaker, because using alum is a very common method for removing broken screws. You can refer to it as "corrosive liquid" if you want, but you can hold your finger in it all day long and the worst that will happed is you will get a wrinkled finger like being the bath too long...it only dissolves steel as I said clearly above.

You could also spend the money to by some vissen screw dissolver, sold currently by Bergeon I think, but you might actually have alum in the spice cabinet already.

https://www.cousinsuk.com/product/vissin-screw-extracting-fluid

Look mate removing a broken screw is a simple and routine task for any competent watchmaker. If this is something over your head, I would suggest taking it to someone who knows what they are doing before you cause further damage.

Cheers, Al

 

OK Here's the scoop: I had the watch serviced for a whole lot of (too much) money and told the guy I was selling it and didnt have an immediate purchaser. He said it would be fully warrantied. I took it as a given that it would be fully warrantied and that if that was his response to my point, he must be telling me that he would warranty his repair from when it started to be used. I sold the watch some months later and immediately the buyer started wearing it and having to wind it, that screw broke. I took it back to the repairer and soon discovered that he doesn't actually do his repairs and could not remember giving this one to whichever repairer he, in turn, uses! He now pretends that his repairer can't get the screw out especially if I don't want to pay for what he calls this labour-intensive repair.

So I was wondering, within the context of remembering how the other bloke got that other screw out, how unreasonable I was being in expecting him to get the screw out (Now that I remind him of our agreement)

The watch, FWIW, is a generic sterling silver demi hunter with a rose gold bezel on the outer cover around which are engraved roman numerals. The movement is an equally generic 15 jewel Swiss Made movement which I can't easily identify as a Schild, or a Tavannes, or a Fountainmelon etc so I kept quiet about this generic question so as not to cause offense, which I seem to have managed to do by it not being a Seamaster! SORRY! from what I remember about this generic movement, it looks somewhat like this one, except that the First Wheel is (obviously) secured by the screw which has broken, and not this larger mounted assembly.

 

I Can't give any repair advice other than take it to an expert and buy the bullet on cost. I CAN give some personal advice though: "When asking for advice and receiving feedback, be polite, specially when the responses and help is entirely voluntary."

For what I read it does not seem to me like anyone is expecting your watch to be a speedy, nor expecting you to apologize for it. Just requesting information so more detailed help can be given. anyway, good luck with that loose screw.

 

Okay - well as much as you seem to think I am being a movement snob here, I am just trying to help someone who doesn't seem to want to cooperate much. I don't care what the movement is (Speedmaster or Seamaster or something completely different), but giving me information does help, even if YOU feel it is a generic request for information. For example, if it is the screw that you show in that photo, that is the ratchet wheel screw that threads into the barrel arbor. The first question you ask is a bit misleading since you ask hot to remove a broken screw that is "by" the barrel arbor, not "in" the barrel arbor itself.

In this case alum won't work, because even dismantling the barrel to get just the arbor out still means the steel arbor would be eaten way by the alum, as the screw is also being eaten away. Again this is why I need details to advise you properly...

So in addition to the alum not working, the screw extractor will also not work, because it is designed for use on through holes only, not blind holes like a barrel arbor.

You can soak this in an ultrasonic tank all you want - if it's loose enough for that to have an effect, it's loose enough just to remove it with a pair of tweezers. So if can't be teased out, the tank idea is not going to help.

If the screw is broken off flush then you can't use a screw slot file to create a slot to use a screwdriver.

So assuming none of the techniques above can be used, then yes this is not an easy extraction in this case, but it can be done. One thing that can be tried is to drill out the very center of the broken screw with a small diameter drill, and then tap a cutting broach or a very small "easy out" into the hole you just drilled and unscrew the broken part of the screw. This risks breaking a drill inside the arbor, or breaking the broach inside the arbor if the screw is in there really tight.

The only other thing that comes to mind is laser welding a rod to the broken screw end, and then using that to turn out the broken part.

I know you keep hoping there is some magical technique that solves all your problems in this case, but there isn't. When a screw breaks, sometimes the tension is released when the head snaps off, and the remains are free to be turned out easily. However before the head breaks off, very often screws will distort/stretch as they are stressed, and this causes the threads to bind in the hole, so when the head does finally break off, the remains are jammed in there tight.

I can't tell you anything about parts availability with the only information given being a generic movement that might sort of look like the picture you posted.

The story about the warranty doesn't make a lot of sense to me - warranties come with a time limit, so if it is within that time he should repair it under warranty, and if it's outside that time limit then it's on your dime. When the watch was used or sold does not really come into the equation. The watchmaker has no idea when the watch has been used after you pick it up, so in practical terms a warranty can't really be started at some random date in the future that the watchmaker doesn't even know about. But all that is between you and him.

Cheers, Al

 

Hey, steady on Sergio old chap, not sure what you were reading into my post but I was completely unaware that I was being in any way impolite? Did Archer think that I was being either impolite or ungrateful for the very full and correct advice he was giving?

 

Can't speak for Archer, I don't know him. Was just going from my own reading. Perhaps I misread your tone, I apologize if that is the case.

 

Far from honouring a warranty on a watch this guy forgot even doing, he is not claiming some time limitation, he is now claiming that he never even repaired it!

Sorry I couldn't identify the unnamed generic movement which I do not have here but I am getting it back now and will post photos of the exact problem when I do.

 

Sorry for delay on this but I was mistaken on which screw it is: I have now retrieved the watch and it doesn't seem as bad as I thought, though it must be pretty difficult or the repairer should have been able to get the stump out. It is in fact a stump protruding from the hole and not a piece buried deep in the hole as I thought. But still, is this something a competent repairer should be able to cut a slit in, to get a screwdriver in? It looks as if purchase could possibly be got on the stump to get out but I am sure it isnt that easy as it also looks like he has tried this, burred the stump over a bit and given up on.

I am still not sure what make this is, I suppose it may be some sort of LeCoultre calibre?

 

I'll make this one simple: if you can't wiggle the stump end of the screw out with a pair of tweezers or unscrew it with a screw driver in the slot that appears to have been cut/attempted, you should refer this problem to a competent watchmaker for repair. Al has given you many techniques to do this job, but in your case, sometimes it's best to know when you're in over your head at the risk of doing more harm than good.

 

Broken crown wheel screw - quite common since these are often a left hand thread, so people who don't know this turn it CCW to loosen it, and snap the screw head off.

Photos are quite blurry, but it looks like there is a good amount of the screw sticking up, so if it can't be gripped directly with tweezers or a pin vise, then yes I would cut a slot in the remains of the screw, and use a screwdriver to remove it.

The file you need is quite specialized, and they are not cheap - I have taken a photo of one of mine next to a set of tweezers to show the scale:



They have teeth so fine you can't see them with the naked eye, and the whole file is quite thin - the actual edge is thinner than is shown here:



Good luck.

 

Thanks for that exceptionally helpful response which tells me everything I need to know to deal with this repair. I suppose the problem would be with trying to figure out whether this is a reverse thread or not before grabbing what's left of that head stump with a pin vice which is bound to damage it if turned the wrong way with any force at all..

Does anyone recognize the calibre?

 

It appears you have a portion of the broken screw left, and it seems that has threads on it. So if that's the case, you just need to look at that to determine what hand the threads are mate.

And for determining the caliber, once again more information is needed - ligne size for a start, and ideally a shot of the dial side of the movement with the hands and dial removed, showing the setting parts in detail. That is how most unknown movements are identified, not by the top plate parts, but by looking at the shapes of the setting parts using a Bestfit book for example...