Junghans Time & Strike Mantle Clock - Repaired Sept 2016
Here we have a nice Junghans time & strike mantle clock. The problem description is the clock runs for a few minutes then radically stops. The clock was recently oiled with penetrating oil instead of regular clock oil. This oil must be removed. The movement will need at least a complete disassemble and cleaning. While the customer was dropping off the clock, he demonstrated how the clock would stop and the angle of the pendulum rod was cocked. This would imply a bent escape wheel tool. We will see if this is the case.
To the right is the clock before disassembly:
My first thought was a possible bent escape wheel tooth causing the movement to stop. Testing the motion after removing the movement from the case found there was no problem with the teeth. I did find numerous (9) worn pivot holes. These will need to be repaired. See the videos below:
The clock was then disassembled. The escape wheel teeth were examined. There were 4 teeth that were marginally tipped. These were straightened. All the wheel pivot holes were examined for roughness. They were all good. No polishing needed. The next step is removal of the mainsprings from the barrels. Here is an image of the mainsprings with barrels and barrel caps before steel wool and cleaning.
Interesting on this Junhans time & strike movement, the barrels are different sizes. And even more interesting is the strike barrel is smaller than the time. The movement was rebuilt and cleaned. There were 9 holes that were worn. Bergeon brass bushings were installed. Here is a short video of the clock running on the test stand. Note: the strike levers have not been installed yet. The movement is running dry except for the mainsprings. This is only done for a short time. If adjusts or disassemble are needed, this can be done without getting oil all over the movement again. Backing up in time. Remember the customer demonstrated the radical stoppage of the movement with the pendulum rod stopping at an angle. The escape wheel teeth were inspected with minor straightening needed. I was able to recreate this having the verge too low on the escape wheel. In general, I like to have the verge as low as possible to get the best swing of the pendulum. If it is too low, the teeth will not escape. This adjustment was made and the clock is cooperating wonderfully. Click here to see the video.
Next step, strike levers installed & oiled and finally back in the case. The clock is complete, hammer adjusted, case oiled, glass cleaned, running well. The last adjustment is the speed. This process takes anywhere from a couple days to a week. As a general rule, the repaired clocks are run for at least a week checking to make sure it is running as designed. Here is a final picture of the completed clock:
Beautiful Clock! A pleasure to work on.