Camerer Kuss broken lantern pinion

[digitalpan]

Hi everyone

Yesterday a lady brought in a 12 inch round dial wall clock marked Camerer.Kuss on the dial (photo taken after I had removed the hands):



She said that she was winding it and there was a loud bang and the winding key went loose. When I took the back off I had two surprises:



1. A wooden movement (German Black Forest I guess, but not a striker) and
2. two small bent pins in the bottom of the case.

I popped the movement out of the case and found that the spring barrel simply turned in both directions and was not engaging with the rest of the train. The spring seems to be intact. The two small bent pins were the remains of two trundles/leaves from the lantern pinion which engages with the spring barrel great wheel. Here's what was left:



The spring barrel and great wheel are at the bottom. The brass ends of the pinion have been badly damaged when the pins were ripped out, and the entire pinion will need to be replaced. But I am intrigued that the spring was capable of doing that without seeming to damage any brass teeth, and it set me wondering whether the spring might have been replaced and be too strong for the clock. There is a repair label from April 2013 on the clock (from a reputable local shop), but no clue as to the work done.

It set me wondering whether I should set it up temporarily to be weight driven; maybe I could see how much weight is needed to make it run, then somehow compare that to the force from the spring. Has anyone done anything like that?

Best wishes

Ian

 

[Chris Radano]

Although your idea is interesting, I would assume unnecessary. It looks like a failure of the brass collar. Probably a casting weakness that took a while before resulting in total failure.

 

[digitalpan]

Hi Chris

Good point about the casting, and the pins seem to be very close to the edges. But my main concern was that the spring had badly bent the two steel pins, which would take a lot of force.

 

[Chris Radano]

If the spring is original, I would keep it. Your photo is interesting. There appears to be no wear on the pins. So many times, with American clocks, the diameter of the pins is eaten away with wear. Machines.....they make us go

 

[GregS]

This is very interesting. Your questions regarding the mainspring along with a recent repair date makes me wonder if the spring failed, was replaced, and the damaged trundles were overlooked, only to fail completely a year later. Also interesting is that only one end of each trundle is still shiny. As noted the trundles were set very close to the edge of the lantern caps. Clearly the caps could have been a mm or two bigger. I especially like the lantern end cap holding the trundles in. A very nice alternative to the usual staking or knurling.

 

[David S]

Have you checked the spring for a break or the retention failing? Something has hit those trundles pretty hard to bend them like that.

 

[Tinker Dwight]

It is possible that the clock had stopped with a full
wind and they'd force more wind, adding the springs
force with the force of the wind. The combination of
weak caps, weak pins caused it to fail. I can see additional
holes in the picture. One wonders if these are all replacement
pins and not hard enough.
Do also note that the other pins are not bent. Only the two.
I don't think it was a spring problem unless the spring end
let loose.
Tinker Dwight

 

[digitalpan]

I've not had the spring barrel apart yet, but I did just try to straighten one of the bent trundles, and it was easy with a pair of fine pliers, so the trundles may only be soft steel rather than the "pivot steel" we might expect. Anyway, it's going to need a complete replacement, particularly if the trundles are soft, otherwise it's just going to happen again.

Does anyone have any approximate measurements for springs for this type of clock? The only wooden frame clocks I have worked on have been weight driven, with very modest weights.

 

[R. Croswell]

The real question is whether the broken pinion is the cause of the problem or the consequence of a spring/ratchet failure. When a barreled spring breaks or "lets go" the rapidly revolving mass of the spring develops a tremendous amount of kinetic energy - like a revolving flywheel - when the spinning out of control spring expands to the diameter of the barrel all of that energy is released suddenly wrenching the main wheel with a tremendous but very brief force. The pinion damage looks very much like the result of that type of failure. Had the pinion failed first it likely would have made a hellish racket and the sound of the main wheel spinning briefly at high speed and would not likely have been described as a loud "bang".

I would suggest that step one would be to disassemble the spring barrel and remove the spring and inspect the click and ratchet wheel and try to determine if something here failed and caused the pinion damage, or if indeed the pinion just gave up. The severely bent trundles seem to suggest that an excessive force was encountered tht could only come from a spring or click failure.

Repairing the damaged pinion presents some interesting possibilities but I believe it can be done.

RC

 

[R. Croswell]

.........but I did just try to straighten one of the bent trundles, and it was easy with a pair of fine pliers, so the trundles may only be soft steel rather than the "pivot steel" we might expect. ..........if the trundles are soft...........it's just going to happen again.

Not sure what one would expect to find in a wooden clock like this but I find a lot of American clocks that have relatively soft pinion trundles that run fine for years. If soft trundles was the cause of this failure I would expect to see some signs of bending in the other trundles. I could be wrong.

RC

 

[Tinker Dwight]

I agree with both RC's post.
Tinker Dwight

 

[digitalpan]

I just took out the spring barrel and popped off the cover and the spring seems fine, occupying about 1/3 of the barrel, attached at both ends, nicely lubricated - in fact it looks like NEW (but I can't be sure!). The click and ratchet wheel, while not the best, are not the worst I've seen, although the spring wire is a bit short. Here's a photo:



So if we discount a broken spring as the cause of the failure, I am left with pinion failure as the cause. But how? If there was no sudden blow (like a spring breaking) there could only be the pressure from the spring (acting normally). Which is my nagging thought that the spring is too strong.

I'm confused! I know I have to replace the lantern pinion, but I don't want events to repeat themselves.

 

[harold bain]

I would replace that click spring, as I can picture it sliding down the click over time and not allowing a proper drop on winding.

 

[Tinker Dwight]

'Still could be the spring. Remove the arbor and check
the hook.
I'm still thinking the person might have forced the
winding rather than the spring coming loose.
You still need to check the spring and ends to make
sure.
Tinker Dwight

 

[R. Croswell]

I would replace that click spring, as I can picture it sliding down the click over time and not allowing a proper drop on winding.

I agree - and its awfully close to the end of the click.

Did you actually remove the spring from the barrel and have a look at the anchor pin on the arbor? Does the inner coil of the spring seem to wrap completely and snugly around the arbor?
If you didn't remove the spring, I would do so. I seriously doubt that the size of the spring is the root of the problem but once it is out you can provide the thickness and width and that might give a clue. I'm still thinking the problem originated with the click or the spring in the barrel - if not busted, then slipping of the anchor pin perhaps.

Yes, cast parts are more prone to sudden failure and perhaps it was just a stress crack failure but it really looks a lot like something else.

How are you proposing to repair/replace the pinion?

RC

 

[ANTIQUECUCKOOCLOCK.ORG]

Nice clock...

 

[Jay Fortner]

This clock having a barreled spring makes me think someone got too aggressive with their winding,applied too much force when the spring wound tight. I also noticed that there are a lot of extra trundle holes in those caps which would make it weaker. Whether you are going to repair it yourself or farm it out I think it would be best to;
1, Make the caps at least 1mm larger in dia.
2, Only put in the number of holes needed for that number of trundles and,
3, Use hardened pivot wire.

The click spring can be used if you take some of the bow out of it so it will reach the top of the click and untwist the coil slightly so there is enough pressure to reset the click.

 

[Chris Radano]

Digitalpan....Guess what? I now have a clock with a similar movement in my collection. I will post photos later. By the way, It's a Winterhalder + Hofmeier clock.

But for now, here is the problem with your movement. Besides the click spring, it appears that the front plate has split down the middle. Furthermore, there is a split on the bottom board (not sure if it's the same, or related, split). Someone has attempted to repair the split with a brass bracket, seen at front bottom.

Perhaps, this movement has "bit the big one"?

 

[Chris Radano]

One thing may do the trick to save your movement.

How about 2-3 thin metal bands (or clamps, or straps) that would span the width of the front plate to secure the plate from flexing width-wise. The bands would have to be thin, and not interfere with any pivot points. I'm thinking something that would wrap around, that would somehow secure with a small screw for removal when servicing. Or, perhaps bands that would be permanently affixed to the width of the front plate. It's a stretch I know, but seems like a solution in theory.

I know that spring is large, so the movement would run 8 days.

 

[R. Croswell]

One thing may do the trick to save your movement.

How about 2-3 thin metal bands (or clamps, or straps) that would span the width of the front plate to secure the plate from flexing width-wise. The bands would have to be thin, and not interfere with any pivot points. I'm thinking something that would wrap around, that would somehow secure with a small screw for removal when servicing. Or, perhaps bands that would be permanently affixed to the width of the front plate. It's a stretch I know, but seems like a solution in theory......

I would not call the undertaker just yet, and I would hesitate before installing bands and external patches. Cracked wooden clock plates are not uncommon and modern glue will usually repair the crack such that the joint will be stronger than the original wood. Of course the movement will need to be completely disassembled and the crack will need to be cleaned first. It will need to be clamped both horizontally and vertically to make sure it is flat as well as tight. Wax paper will keep any excess glue from sticking to the surface against which it is assembled. It is important that the crack close together well when it is clamped. Now if the wood is oil soaked all bets are off. The last one I did (a somewhat different movement) I used yellow carpenters glue. I am not sure about the thicker CA glues (Super Glue Gel) which seems to work well in other applications.

RC

 

[shutterbug]

I think I'd stick with wood glue, and follow RC's recommendation.

 

[Chris Radano]

Wood glue it is! I don't know why I didn't think of that because I've used modern wood glue before

I use Titebond "weatherproof" wood glue. When clamping, I have a wet rag handy. I wipe the excess glue off, then I usually will return to check on how the subject is doing several times over the course of several hours, say every 30 minutes or so. Sometime the clamps will need fine adjustment. Sometimes, there will be more glue seepage (a small amount after the initial wiping).

If I do a good job, which it will be after all that attention, the repair will be invisible, depending on the break. Or, at least barely visible unless under close inspection. It's the least I can do for my antiques.

 

[shutterbug]

In the mean time, I'll move this over to the wood clock forum for their ideas.

 

[digitalpan]

Hi everyone, and happy new year (a bit late, but it's my first post of 2015!)
Chris, thanks for your observations, I would say that your movement is the same as mine. Do you by any chance have the spring dimensions? I will be working on the clock in a few days time and it would help to confirm or deny my theory that the current spring is too powerful.
I will be turning a new lantern pinion in one piece using the method in Penman's Clock Repairer's Handbook. My challenge at the moment is working out a way to retain concentricity when I drill the trundle holes. I did refer to Wild's Wheel and Pinion Cutting in Horology but he always seems to have a specialist piece of equipment for every job. I will post some photos when I've got going on the task.
Best wishes
Ian

 

[Chris Radano]

Hello Ian, I am running my clock right now, so I apologize I will not be disassembling the movement.

I can say, the movement of my clock is fairly accurate upon winding for 6 days, the last day the movement loses about 2 minutes. So, I wind another turn about day 4 or 5, and the movement is fairly accurate over the course of a week.

The spring is indeed very strong, and winding requires a strong grip and wrist.

You didn't say if the you glued the front plate together. You could try that repair, but unlike the common 30 hour weight Black Forest movements, there is considerable force exerted on the plate by the strong spring. So, I would let plenty of time for the glue repair to set, if that's your method of repair. There is no doubt the spring would bust through the repair you've photoed.

Unless you keep the original spring aside, and install a smaller spring? The movement would have to be wound more frequently.

Here is my clock with the similar movement:

https://mb.nawcc.org/showthread.php...ut-Camerer-Kuss-c-1875&highlight=Camerer+Kuss

 

[digitalpan]

Pressure of other work has delayed the Black Forest until this week. I started by cutting out all the old trundles and was able to knock off one cap. The end by the wheel had to be turned away:

Then I machined a complete pinion like a bobbin, and following Jay's advice I added an extra 1mm on each side:

It's mounted on a length of steel rod in a collet in the headstock with a centre at the outer end. Then I could set it up on the rotary table on my small milling machine:

There are 15 trundles so it's drill every 24 degrees. The trundles are 1mm diameter so it's drilled 0.95mm - I'll broach out the holes by hand for a tight fit and fit the original cap to retain the trundles.