Bushing Position

[wow]

I am working on an old German AMUF tall case clock and found this T-1 sprocket. It’s a good example of what happens when a bushing is misplaced. Someone bushed the plates on this T-1 arbor and the one nearest the wheel was not centered and this is the results. It evidently ran for years with the T-1 too far away from the T-2 pinion and all the teeth are deformed. This is why depthing is so important.

 

[Willie X]

I would suspect the amount of weight too.
Willie X

 

[R. Croswell]

The position of the wear does not look like the wheel and pinion were too far apart. I agree, depthing is very important and even a little extra friction over a long period of time could do damage. I also wonder about the quality of the original material, and along the line of what Willie said, perhaps the gear design was just inadequate for the intended weight.

RC

 

[bkerr]

What does T2 look like?

 

[wow]

What does T2 look like?

You can see it in the second photo. This is how I found it. If you look closely you can see that T-1 is slanted and meshes on the left side of the T-2 pinion. I raised the bushing on the left end of the T-1 arbor and now it is straight and meshes as it should. I think Willie and RC are right about the weight of the weights being too heavy. That may add to the pressure on the T-1 teeth. As you can see, the whole movement was filthy. After cleaning , polishing pivots, and a few bushings, I hope it will run. Not sure about T1 though.

 

[R. Croswell]

You can see it in the second photo. This is how I found it. If you look closely you can see that T-1 is slanted and meshes on the left side of the T-2 pinion. I raised the bushing on the left end of the T-1 arbor and now it is straight and meshes as it should. I think Willie and RC are right about the weight of the weights being too heavy. That may add to the pressure on the T-1 teeth. As you can see, the whole movement was filthy. After cleaning , polishing pivots, and a few bushings, I hope it will run. Not sure about T1 though.

I agree, there is/was an alignment between T1 and the T2 pinion, but not sure what is "slanted" or how you fixed it. If you mean that you moved the left T1 bushing upward relative to the picture (toward the T2 pinion) and that now T1 is more centered in the T2 pinion, I predict that you may have a problem. Moving the bushing to center T1 in the pinion will also move T1 closer to the pinion. Over time, the trundles of the T2 pinion have caused excessive wear to T1 forming a "shelf" in the side of the tooth face. With T1 relocated, the trundles will tend to impact the bottom of the shelf and cause a binding action and loss of power. This is a common problem when old parts have "run in" for years without a problem but get upset when relocated or a new part is introduced next to a worn part. Perhaps you could have lowered the right bushing to bring things into alignment without increasing the depth of the mesh?

The question remains, how did it get this far out of alignment? Was that left bushing worn excessively? Can't help wonder if T1 is a replacement part. That T2 pinion seems to have long trundles for a 2nd. pinion, I wonder is someone slipped the left shroud to the left to gain clearance for T1? I would check the end shake of the trundles, to make sure they are adequately captured in both shrouds. You may be able to flip that T1 wheel and use the unworn face of the teeth, as it is, I predict it has a limited life expectancy.

RC

 

[Willie X]

Is the main wheel pivot badly worn?

This could be simply a very high mileage clock that ran in very bad conditions. I don't think you ever mentioned the amount of weight?

Old American clocks do this all the time. And, if you change the wheels positions, the clock may not run anymore due to what RC just mentioned.

Willie X

 

[shutterbug]

I agree. I have occasionally (but rarely) come across a wheel like that. Usually they were just massively over powered.

 

[roughbarked]

I'd be looking at the trundles.

 

[wow]

Sorry about not responding. Been out of town. The clock has had lots of work on it. I weighed the weights and the time side is 8.2 lbs.
When examining the time train after cleaning it up. I found several bushings that had been installed at some point. When the T-1 teeth were meshing with the T-2 pinion the trundles were only about half way into the teeth and not meshing as deeply as they should. The worn sections of each tooth showed the place where the trundle ran. I rebushed the wheel end of the T-1 arbor cutting it so the pivot would be moved about 2 mm. which allows the teeth to mesh deeper into the pinion. I also had to re-shape every tooth slightly for the train to run smoothly when under finger power. I think RC is right about the wheel being a replacement. If reshaping it doesn’t do it, I will try flipping it. It’s not brass and is not centered on the T-2 pinion. Some soft metal like aluminum or soft steel. I don’t know about the weight. Is 8.2 too heavy, Willie?
I plan to put it on a test stand tomorrow and see what happens. I may need a new T-1 wheel.

 

[R. Croswell]

...........When the T-1 teeth were meshing with the T-2 pinion the trundles were only about half way into the teeth and not meshing as deeply as they should. The worn sections of each tooth showed the place where the trundle ran. I rebushed the wheel end of the T-1 arbor cutting it so the pivot would be moved about 2 mm. which allows the teeth to mesh deeper into the pinion.

The pictures do not seem to indicate that the wheel and pinion are too far apart. The wheel and pinion should contact at their respective pitch diameters. I'm afraid that reshaping those worn teeth will weaken them.

Please visit this AWCI link: Lantern Pinion Depthing (awci.com)

It has photos of lantern pinions with too shallow, normal, and too deep engagement. It also has a great illustration showing the pitch diameters and just how deep the pinion trundles should be into the wheel.

Also be careful with small lantern pinions, if the depth is extreme, the tips of the wheel teeth can contact the arbor in the center of the lantern pinion.

RC

 

[Willie X]

8.2 might be a little on the heavy side but certainly not the cause of all this. Might be a poor materials thing. Willie

 

[wow]

Well, here it is running. We’ll see what happens.

 

[wow]

It ran about one hour and it stopped. I took out the T-1 arbor and wheel and put it in the lathe.(should have done that from the get go). The wheel wobbled and was slightly out of round. I separated it from the arbor and flattened it on an anvil with a brass hammer. I topped off and shaped the high teeth, flipped it and put it back together.
You guys were right on target. It is not the original wheel. I think someone made it out of aluminum. A magnet will not attract. The bushing they put in allowed the out of round wheel to mesh deeply on one side and shallow on the other but still run. I centered the pivot where it is the right depth now (I hope). The warp in the wheel somehow started rubbing on the lantern pinion cap. Now that there is no warp, it meshes straight on the trundles. Flipping the wheel helped. Thank you all for your input. Here’s a video of it running now.

May 28, 2022

youtube.com

 

[R. Croswell]

Looks like it is running well. if it continues for a few days, you might try reducing that 8 1/2 pound weight a little to have mercy on that aluminum (or whatever it is) main wheel.

RC

 

[wow]

Looks like it is running well. if it continues for a few days, you might try reducing that 8 1/2 pound weight a little to have mercy on that aluminum (or whatever it is) main wheel.

RC

I just switched the weights. The one I had on the time side was the heavy one. Now that it is running well, I agree, it’s a little too robust. When I left the shop it was running great with the lighter weight. That’s how they should be anyway because the strike side lifts four hammers. Thanks, RC.