I’ve recently completed a restoration and service of a Lenkirch bracket clock. Lenzkirch clocks from the town of Lenzkirch in the Black Forrest region of Germany were made between 1851 to 1929. The company was originally founded by Eduard Hauser whose company established a reputation of making reliable clocks with outstanding craftsmanship.
The clock I worked on is pictured below. It has the serial number 879837 stamped on the rear plate which dates it to between 1895 and 1900.
It is a quarter chiming “ting tang” movement. You can see the 2 circular gongs looking in the rear door of the case.
Externally the case was in excellent condition with a few missing wooden mouldings, but they were all found carefully stored inside the case. It even came with its original distinct Lenzkirch winding key.
The silvering on the dial was however wearing a little thin where I suspect it may have been polished at some point in its life. I decided that it didn’t need resilvering in this case and left it as is.
Upon extracting the movement it didn’t look too bad. It hadn’t run for many years and was mostly suffering from congealed oil making the movement stiff.
Some screw head damage from incorrect screwdrivers.
And oil in places it shouldn’t have been oiled, but certainly not as bad as some movements I’ve worked on.
A close inspection of the clock revealed the following problems:
- Mainsprings set and coned
- Rear pivot hole on centre arbor worn oval and scoring of the pivot
- Slight wear to surface of pallets
- Escapement pinion very badly worn with a rough surface.
You often see this kind of wear on a clock with a recoil escapement. The forward then backwards recoil with dirt and oil in the wrong place have gradually caused this. It wouldn’t be good to continue to run the clock in this state. Options for this fix are:
- Make a new arbor and pinion (a good fix but poor conservation)
- Use laser or micro welding techniques to build up the worn area and file the pinion leaves back to their original shape. I don’t have the equipment for this, but this is something I’d like to explore in the future as from a conservation point of view it really preserves the clock in the most original condition.
- Make the 3rd wheel mesh with an unworn section of the escapement pinion. There are a couple of ways this could be achieved, firstly the 3rd wheel could be moved along the arbor which in this case wasn’t easy as the wheel was riveted to the pinion on that arbor. The other option was to move the escapement pinion somehow.
I decided that the option of moving the escapement pinion along slightly was the least intrusive option here. I did it by shortening the arbor at one end and repivoting. To get the correct endshake back I extended the arbor at the other end.
You can see the result at the shortened end here when photograph during a trial fitting:
You can just about see the join where I have extended the arbor at the other end if you look carefully.
The other repairs were quite straight forward. The collet for the escapement pallets needed moving along and were reset to work on the unworn section of the pellets. Mainsprings were replaced, the plate was rebushed and all pivots were polished.
After final cleaning the following lubricants were used:
- Mainspring : SAE 120 / Moly grease 50:50 mix
- Barrel arbor: Moebius HP 1300
- Remaining arbors and pallets: Moebius HP 500
Regulation was performed using the Microset timer where I needed to achieve a rate of 9558.8 bph. I used the acoustic pickup as this conveniently clamped onto the pin for the suspension spring. This works well for checking it is in beat, but the rate readings go wild with a chiming clock every 15 minutes!
The optical pickup would have been better, but this is being used long term on another piece I’m testing.
You can see here the rate is getting close but a little slow at this stage.
The clock has now been tested for a period of 5 weeks. Usually 2 weeks is necessary to prove all is well, but the Covid 19 lock down is resulting in extended test periods at the moment.