Why is my clock striking 12 continuously?
 

Very odd. My tall case clock has always run perfectly. Still keeps great time. But for the last few days it strikes twelve times on every hour.

Anyone know what might be stuck? And how I can get it unstuck? Old clock from about 1850 as I remember.

Would picture of the clockworks be helpful?

Pull out that mouse that got jammed in the gears :)

Visual observation of the movement when working might reveal something. It should be repairable. Even just something needing lubrication.

Did you get the lifetime warranty when you purchased it new?

Will have to ask my mother-in-law.

There are two common mechanisms used for striking clocks.

The first is a counting wheel, which is a wheel which revolves once every 12 or 24 hours. Along the edge, there are notches. As you go around the wheel, the number of degrees between the notches increases. A counting arm will ride around the the outer circumference of the wheel, and allow the clock to strike until it falls into a notch and locks. It's very difficult to get this sort of mechanism to fail in the manner you describe. The usual failure mode is for it to ring until it runs out.

The second type of mechanism is the rack and snail. When it's time to ring, a rack drops onto a spiral cam driven off the canon pinion. A gathering pawl then reloads the rack one tooth at a time until it gets back to it's resting position. In order for the clock to ring 12 times every hour, the rack would need to miss the snail and fall onto some sort of backstop. Which suggests that the snail has become detached, or if that it's gear driven and the gear has stripped. If you can remove the face and photograph the mechanism, I may be able to give you a better idea.

Although this isn't the most complicated repair, it's not something you just go do unless you have experience with clockwork mechanisms and proper tools. Not only are the parts delicate, but the gears have to be oriented properly for it to work. If you don't know a local clock repair shop, try the boards at Welcome to the NAWCC!.

M - great info. Just what I needed. Will look into it and post some pics.

Much appreciated.

Be very careful - do not ask for whom the clock tolls ...

Mxfrank - OK; here are some pics. Do you see anything?

http://i303.photobucket.com/albums/n...psevt9rnlr.jpg

http://i303.photobucket.com/albums/n...psexc1gxr4.jpg

http://i303.photobucket.com/albums/n...psucsjkwsa.jpg

http://i303.photobucket.com/albums/n...psi3kmmrzb.jpg

http://i303.photobucket.com/albums/n...psqfucr2lq.jpg

Nice clock. I'm going to guess British, early to mid 19th century.

You would need to remove the face to get a clear picture of the strike mechanism. From what I can see, you have some loose string caught in the strike train. You can clean this out with a pair of tweezers. I don't think it's causing the problem, but it's not good to have loose stuff in the movement. Also some cobwebs which you should blow out with a pressure duster. The movement appears to be very dry and could use a teardown and fresh oil. I really recommend a professional overhaul. If you want to try this yourself, you would do well to join a local chapter of NAWCC and find someone willing to work with you. You really need to get someone to nurse you through the apprentice stage. I'll talk you through this as best I can if you really want to do this online. Before you do any work, it's best to remove the pendulum and weights.

I'll tell you how to remove the face, but if you are at all uncomfortable, just stop. And remember, anything you break will have to be made from scratch. It's a good idea to cut a piece of cardboard to protect the face as you work. First remove the hands. The seconds hand should just pull straight out. The hour and minute are most likely pinned. The pin may be either straight or tapered. If it's a taper pin, you want to grab the fat side of the taper and pull straight with a pair of pliers. There will be a washer under the pin, and then the hour hand will immediately come loose. The minute hand is friction fit to the cannon and should pull out without much drama. To remove the face, there will be four pins that mount the face to the front plate (don't confuse them with the pins that hold the plates together). When all four pins are out, the face will be free. See the annotated photo below.

Yes, I have had the face off several times over the past forty years. Will do it later and post some pics.

Appreciate your help.

What I expect you will find is something like the attached photo. When the clock reaches the hour, a follower falls onto the snail and allows the rack to drop a controlled distance. The rack is then gathered up one tooth per revolution of the strike mechanism. The snail may be loose on the pinion, which would require it to be staked, or the follower is out of position for some reason. You can work the mechanism by installing the hands without the face. Advance the minute hand until the strike sequence begins, and observe what happens.

Will be able to look at it later today; obligations now.

Thanks.

I do kinda remember seeing the snail mechanism in the clock from years back. At that time it would only strike ten times at 11 and again at 12; otherwise it struck the right number of times.

Has struck like that for years (1-2-3-4-5-6-7-8-9-10-10-10-1-2-3-etc) until mysteriously this week it started striking twelve times on each hour. Is an interesting challenge and I like being educated anew.

Whens the last time you serviced it? could need a good cleaning and oiling, I have 2 down right now for just that, I'd love to see the whole clock, I'm starting a bit of a collection....

Here's an old diagram explaining the mechanism. Each clock is different, but the conceptual mechanics will be the same.

What you're looking for is some sort of problem between the rack and snail. It could be that the snail is loose on the canon pinion. For that vintage of clock, it's probably staked in place and you don't want to attempt that repair without practice. The other possibility is that the cam follower or spring is broken, fouled, or sticky. You fix a clock with your eyes before you fix it with your hands.

This forum never ceases to amaze me with the depth of knowledge of the membership.

Mxfrank - thanks for the exhibits; need to study. Meanwhile here is a pic and a video of the mouse and snail mechanism striking. I see one brass piece which has obviously been repaired in the past and cannot tell if it is intact or if something has been broken off the end.

Please give me your thoughts.

Thx.

http://i303.photobucket.com/albums/n...psooiwriki.jpg

http://i303.photobucket.com/albums/n...pspcnuoxar.jpg

http://i303.photobucket.com/albums/n...psno7kcepr.mp4

If you look to the left of the snail, at about 7 oclock, there is a spring. It doesnt look original, but no matter. It should be tensioning the rank and follower. If not, thats the problem. The follower looks a bit creative, but its hard to tell in these photos.

After looking at the video, it looks like the sping is ok. What I'd like you to do is replace the hour and minute hands, leave the face off. Then advance the minute hand slowly until the rack releases. See if the follower touches the cam and if the count is right.

Mxfrank - thanks. Tied up now and have Habitat all day tomorrow. So I cannot get back to it for a bit. Will take another video as soon as I can.

Appreciate the help.

Ok, got it. If you look at the first photo, I've market the 12 hours on the snail. The follower will drop onto a different segment each hour. The follower will allow the rack to drop an appropriate number of teeth.

Look at the second photo. The follower has fallen at 7pm, but the cam has dropped to 12. This means that the rack and follower aren't properly synched. You will need to remove the weight, then remove the pin that holds these parts in and see what's going on. But there may be another explanation.

Also notice that there's severe wear on the surface of the cam, and there's something going on with the follower as well. The wear is greatest at 10 and 11, which is probably why it rang the way it used to. My guess is that there was some sort of repair to the follower...maybe an extra bit soldered on which is no more, and that may be an alternative explanation.

Mxfrank - hard day at Habitat today so I have not yet studied your last posts. As you requested here is a video of the clock striking.

Thx for the help.

http://i303.photobucket.com/albums/n...psdaudwqef.mp4

Mxfrank - I note that the follower is not touching anything; not the snail, nothing. Is it supposed to catch in the 1-2-3 notches in the snail? If so, not happening and I wonder if the snail has drifted inward toward the back of the clock so that the clock mechanism works but the follower no longer touches the snail. Maybe a washer behind the snail has worn off and the snail slid back say 1/64th inch so the follower no longer works?

Or is the followerl supposed to have a small protrusion on it which engages with the snail and which might be broken off - looks like I see an old solder repair there.

Very interesting problem; not something I have ever tried to learn.

Thx.

I'm not sure what's happened, but I can guess. The follower is supposed to hit the appropriate step on the snail each time the strike mechanism engages. My suspicion is that the original part broke, probably because someone wound the time side and not the strike side. The follower must have caught on the cam, resulting in the damage between 10-11, and the follower must have broken. The solder suggests that a bit of brass was added as a fix, but is broken off now. Look around inside the case for the missing repair piece.

You can easily solder another bit of metal there, but it's not likely to be a permanent fix. The part can be removed without disassembling the entire movement. First remove the weights to prevent surprises, then remove the pin and washer. The lever and rack should just lift out. I would be inclined to pin the part in addition to soldering. A patch will always be a patch, but you can get it to work for awhile without much effort.

Given the generally dirty and dry condition of the clock, you may want to consider having this fixed professionally. A clockmaker can make new parts, returning it to good running conditioon. The plates should really be separated and the clock cleaned, oiled and rebushed as needed. I'd also replace the cat gut, as there's no telling how long it's been there. It's a nice clock, it would be worthwhile to do it right. I won't attempt to remotely explain how to do this. If you want to do the work yourself, you really need an experienced person looking over your shoulder.

Mxfrank - thanks a lot for you advice. Agree that I need to take it to a clockmaker. Interestingly enough I sent it out of town about five years ago for a complete cleaning and servicing; could the oil have dried out that fast? Was supposed to fix the 11 and 12 strike but said he could not do it.

Do you have any idea what I should expect to spend? The servicing was several hundred dollars and I am not sure exactly what he did.

Thx.

It may just be hard to tell from the photos, but it does look dry to me. You certainly have cobwebs and what looks like some fibers caught in the mechanism, so it's probably time. Five years isn't too bad.

There are two ways to clean a clock. The first is to "dip it in the soup", which is to say, cook it in an ultrasonic cleaner for a time. Afterwards, it's allowed to dry and then oiled.

The proper way is to completely disassemble the clock. Check for out of round bearings and rebush as necessary. Polish the pivots on a lathe. Restring if the gut has become brittle. And then reassemble and oil.

The strike mechanism is going to need some attention. The right solution is to cut a new snail and rack tail. But maybe they can salvage the old parts, I can't know without tinkering. There's also a gear mounted under the snail, which must have driven some sort of complication...maybe a moonphase or calendar dial. I can't see any other parts related to it, so maybe that needs some thought as well.

How much this will cost, I don't want to guess. Clock repair is a dying trade, and I don't want to undercut anyone, especially since I really can't inspect the job.

Oh man, too bad Carlton Hughes isn't among us anymore. Expert clock repairman he.

2nd response: Is there a raven quothing anything in the background? http://s1.bimmerfest.com/forums/imag...lies/icon9.gif

Mxfrank - very interesting food for thought. Not sure what I am going to do at the moment but I will follow up later.

Much appreciated.

Mxfrank - you were right. I found the broken piece on the inside ledge of the clock. So all I need to do is get someone to resolder these two pieces together.

Since you seem to know what you are doing, any chance you could make this solder repair? Do you think that I might just epoxy it or maybe use JWeld? Not sure.

See pic.

PS - the string that you saw in the gearing turned out to be the desiccated body of a small spider as if he had molted.

Thanks.

http://i303.photobucket.com/albums/n...psrajgvp3r.jpg

Looks repairable and I would reinforce the joint area if practical. Unless by observation there is a chance it failed by something jamming up.

Better to lose a soft solder joint again than have issues with other parts. At least the old girl is going to chine again properly..

Assumptions are dangerous of course as it could have been soldered before with something like five percent silver solder.

I think what should be done is to drill two holes and install pins to give it some mechanical support. I could do this, but without the clock I wouldn't be able to tell if the part was set at the right depth and angle. But PM me if you can't find someone local.

Forgot to say: the words "epoxy" and "clock" should never be used in the same sentence. The solder repair is a bit of a kludge, but at least it's metal.

Mxfrank - took your advice and it is now in the hands of a professional clock repairman. He says at least two weeks before he can do the solder. Says he could build up extra metal on the snail but would be costly; says for sure do not file the snail which is what I contemplated.

Your money would be better spent having a new snail cut than trying to improve this one. Just get used to the odd ring sequence, and let it go.

The most important question...did you have fun? I find playing with mechanicals to be very relaxing.

Yes, a real learning experience; and I get to put it all back together, try to get the thing synchronized so it rings the proper number of times according to the clock face, and slightly bend the rack tail so it catches the snail - terms I had never heard before this.

Meanwhile I get to figure out how to replace a sticking brake caliper on my 81 300SD while I wait for a starter spring to arrive for my Lawnboy mower - also nothing I have ever looked inside before - and I try to get it running again after twenty years (lawnmower, not the SD).

Has been a real pleasure trading ideas with you and I appreciate all the guidance and advice.

I just ordered some more self fluxing with the phosphorous incorporated 15 percent silver solder. I found as I got older I use many more ways to repair things than when younger.

Of course there are more approaches available today. Usually it always works out well fortunately.

What I liked about this thread was that I never repaired a clock. Nor that I have repaired everything by a long shot. Electronics has displaced much of the mechanical world in my time.

While I am not an eco-fanatic, I hurt to see things thrown away when they could be easily repaired. Case in point - I have a 1966 Lawnboy mower which I had contemplated putting out on the street for Atlanta to take away. I downloaded some diagrams from Mr. Google and opened up the mower. The only problem is a broken starter recoil spring. Ordered it for $11 and look forward to seeing if I can get it installed and the mower running again.

I do not need a mower; the yardmen have been doing the lawn for 43 years but I get some satisfaction in bringing it back to life. And I just might give it to Habitat or Goodwill (assuming of course that I really do get it to run again - has been probably twenty years since I broke the spring pulling on the cord).

Mxfrank - huzzah; the clockmaker called today and has fixed the rack tail. Ended up putting four rivets in it and it feels quite sturdy. $40.

He said to reinstall the rack with snail and rack at the one o'clock orientation and see if it strikes one; then check it at eleven to see if it rings the correct number of times.

However so far I have not figured out how to make the rack tooth match the snail tooth as you can see in the photo. I think the clock snail was at 3 and I lifted up the stopper on the rack and placed it in tooth three but it still did not work right.

Stumped for now.
http://i303.photobucket.com/albums/n...psrwjwtxnk.jpg

http://i303.photobucket.com/albums/n...psfqclm6vc.jpg

Synchronization is automatic, as long as the geometry is correct. It's hard to tell from the photo, but it looks like the follower is possibly fouling the hour gear, but maybe not. If this is the case, the rack tail would need to be bent up just a bit to allow it to clear. Also reinstall the pin and washer.

Install the minute hand and turn it clockwise. At some point, the warning lever will lift and allow the rack to fall free. At that point, the tail will swing up and the follower will be in contact with a step on the cam. At that point, the bell count should correspond to the step (one of the diagrams I posted earlier showed the steps numbered).

Mxfrank - yes, I figured that all out. Here is what is happening. When the minute hand gets close to twelve and the rack detent at the top of the mechanism lifts, the rack teeth are freed and the spring (finally figured out to reattach the spring) the spring pushes the rack tail against the snail cam hour by hour and it automatically revolves the rack back so that the appropriate tooth gets caught by the rack detent.

However it acts like the spring is not strong enough because it will not push the rack back far enough; I only get to tooth 4 and cam 4. Nothing is binding. Obviously the spring is strong enough because it moved the rack all the way back to twelve every hour before I took it apart. Do not want to fool with the spring.


Therefore I think I need to oil, grease, or WD40 the spindle that I reinstalled the rack and tail mechanism on. I believe the dry spindle is keeping the spring from working properly. That way the rack and tail mechanism could be pulled all the way back by the spring. Unless I am missing something. When reinstalling the rack and tail mechanism on the spindle, I had to push it on quite firmly to make the rack teeth mesh with the rack detent. (Obviously all these technical terms are thanks to your fine exhibits.)

What do you think? Or we could discuss by phone. My cell is 6 seven ate-77seven-3five0nine. Sorry, do not know your name.

Adrain

No wd40. I have never found a worse long term lubricant. I know they sell tons of it.

To me the product is basically a very poor penetrating product primarily at best. I even suspect that there is very little oil used as the acid carrier.

So what lubricant is used on clocks? I have axle grease, lithium grease, and dielectric grease too. Maybe I will ask Mr. Google. Still not sure why it rotated perfectly on the spindle last week and now binds. Do not think the clockmaker did anything to the cylinder; all he did was rivet and solder the arm.


Quandary. Also wondering if there is any reason not to lubricate the spindle.

Mxfrank - are you out there?

Repaired. I used a bit of steel wool and 3in1 oil on the spindle and it seems to be striking OK now.

The name is faded out but looks something like Runnk Birkalun; Mxfrank had asked.

Thanks for all the invaluable help.

http://i303.photobucket.com/albums/n...psws2jqc4e.jpg

Looks good!

Clocks use a specialized oil, specialized manufacturers, with secret formulas. Traditional clock lubricant was made from a whale oil base. Obviously, this type of oil hasn't been available for many years. Nowadays, it's blended from synthetic oil. For this particular bearing, 3 in 1 is fine because you won't lose time if it thickens, but not for the pivots. The only use for grease in a clock is on mainsprings in spring driven clocks. The trick to oiling a clock is less is more. If you use too much, it leaks down the plate, and because of surface tension, all the oil will be sucked right out of the bearing.

The things you need to be careful of: set the time clockwise only. If your turn the clock back, you will undo all the work you've just done. And keep both sides wound evenly. If you don't like the sound remove the bell but let the mechanism work.

Sounds good again I hope. I could not recommend an oil earlier as clocks needs are beyond my knowledge. The 3 in 1 oil is a far better choice than the wd40 though. It is really oil with no bad additives that I can think of.

you'll find an array of oils here that would suit most needs. Clock Oil and Cleaning Solution

Ha
This is fascinating

I have a grandfather clock that hasnt functioned in maybe 70 years i might try and screw with now after reading this.

Good luck. I found that the striking mechanism was pretty simple once Mxfrank told me to remove the face and take a look. However the actual timing mechanism behind the face - do not know.

But this was an interesting trip and it sure gives a feeling of accomplishment to actually fix something myself instead of paying someone to do it and never learning anything.

Let us know what you decide and take pics.

Luck.

I hope you do... I've made it a hobby to rehab clocks, I've been watching this with great interest. I've never seen an issue like this before, I have a mantle clock I will be disassembling and placing several new bushings in as well as 2 new shafts

Clocks that strike the same time repeatedly are bad Ju Ju. Possessed. I'd sprinkle it with salt and give it away.

Update - clock is still running like a champ. Clockmaker says it is between 1730 and 1800.

Many thanks to Mxfrank for all the knowledge and help two years ago; it was just invaluable. Never could have fixed it myself without his help.

So here is my new question: the gear is missing which drives the calendar hand. Clockmaker says he can make one but it will be quite expensive. And he seems really to have no appetite to do this. Nor will he give me a price. He is actually a really nice guy once you get past the grumpy facade; I like him now that I have gotten to know him a little better (and that was not easy).

Does anyone have a feel for a market price for the clockmaker/any clockmaker to cut this new gear? And one way out question - with today's technology could some machine shop already have one on the shelf as a plain old gear - or could it be 3d printed?

Love this old clock, intend to hand it down to my son, and would like to bring it back to its full glory.

Thanks for the help.

The traditional way to make a gear is to first cut a blank on a lathe, then cut the teeth on a special mill. Finally, hand cut the webbing and stake it to the shaft. About $3000 worth of tools, if you can find them. And a half day to a day of labor. Any price you get may seem high, but price is secondary to finding a specialist who has the skill and equipment to get it done. Finding the exact wheel you need on the shelf is possible, but improbable. This was either hand made or made in a primitive factory, and hand fit to the movement. You could try a company like timesavers and see if there’s something modern that could work.

As for 3D printing, I haven’t seen a lot of this in clockmaking yet. I plan on looking into it at some point, because I need the entire calendar mechanism for a New Haven double dial. Metal printing is not in my budget, though. You might have some luck posting to the NAWCC board. They allow non-members to use their boards.