Turret Clock

This was a departure from the usual for me when a friend asked me to look at a church clock which would only run for a few hours at a time after years with no problems. The strike train had not been used for at least 50 years to his own knowledge, the bell hammer and its connecting wires were no longer present, so only the time keeping was to be serviced and repaired.

Before repair

The clock is sited in a weather proof wooden shed, its too big to call it a box and it certainly doesn’t deserve to be a called a cabinet. The clock is of double frame construction, the barrels stick out at the front instead of being enclosed within the gear frame; this is a very rigid form.  The weights are hung from rope rather then wires and all the pulleys are made of wood not metal, as are the barrels. The barrels wind in opposite directions in order to keep the ropes, when they both had ropes, clear of each other.  There is no maker’s name on the clock anywhere but a brass plate in the ringers’ room below declares that it was given by the local squire in 1840, which would match the style of construction.
There was a lot of grease, oil and associated grime on most of the movement and the green colour on the brass is not the remains of paint but is verdigris .  As you can see in the picture there is also a lot of rusting. I also noticed that one of pivots was loose on the end of its shaft.

I was informed that some repair work had been done on the clock about fifty years before.

Once the clock was taken apart and removed from the tower, quite a job as we had to go up and down an unlit spiral staircase several times carrying, in some cases, only one single heavy part I could give it closer examination.  I cleaned off layers of old oil, grit and candle grease from all the parts and wire brushed the cast iron to remove loose rust. 
The clock’s cast iron parts had pock marks in many places which looked like original casting faults.
The shafts were made up of a lower grade body bearing hammer and file marks, they have higher grade grade pivots fitted at the ends.
Work had been done on the escapement as the pallets were fitted an a replacement frame and attached by cap screws; their depth of engagement with the pallets was much less than it had once been.

Pallet frame with suspension springs to the right.

The pallets are an integral part of the pendulum suspension which has two suspension springs and hangs in the middle of the movement rather than behind it.  The flat pendulum rod passes through a strap on the back of the plate at the left of the picture, terminates in a threaded rod which passes through the boss in the middle of the cradle and is secured by a large wind nut. I counted the turns (43 revs) as I removed this so that it could be replaced in its original position.

Frame conservation.

Once I had cleaned it I gave it a coat of dull, but not quite matt, rust inhibiting paint in the original colour of black.  I took care to keep nuts on their original bolts and studs as these were not quite interchangeable.  Brass bushes were lacquered on their outside surfaces.

Pivot after removal

Repaired pivot

Pallets before

Pallets after

Pin wheel repair

Maintaining pawl jams

Maintaining pawl active

Maintaining pawl at rest

Movement repair:  I have already mentioned the loose pivot and worn pallets so I’ll describe these first.

Pivot repair:  Initial inspection showed the the loose pivot was fitted to its arbor by a cross drilled hole and pin.  Once the pin was out, not quite straightforward as the drilling did not pass right through the shaft and the pin was of steel, I found that it screwed into the end of the arbor and that the screw was off centre. this led me to believe that the pivot was fixed before the assembled shaft was turned true.

 

I made a thin shim that would hold the pivot tight when it was screwed back to its original position and the cross drilled holes in the arbor and pivot lined up.  I then re-pinned it.

Pallet repair:  These were badly grooved and when tested on the back with a file were found to have been left soft instead of hardened.  I later found out that the repairs done about fifty years ago were carried out in the machine shop of o local lorry building firm so it is possible that clockmaking knowledge was missing. The ends of the pallets were identical so I could reverse them to utilize unworn metal, harden and polish them and refit to their frame in the correct position.

Pin wheel repair:  All except one of the pins on the escape wheel were fine, the other was bent and cracked near its base. They screw into the rim of the wheel so it was a sraightforward job to produce a new one from rod and file away half its thickness to achieve the correct form.  This pin could have been bent if the wheel was trying to turn in reverse when the clock was being wound; this could have been the case as the maintaining power was not working.

Repair the maintaining power:  Maintaining power is there to power the clock when the act of winding removes the force of the weight from the movement, it should provide about two minutes drive on this clock. When I first reassembled the relevant parts of this clock I unhooked the maintaining power lever from its resting place on the frame (see first picture on this page where it is at the right hand side of the movement at about the two o’clock position). It engaged with the teeth on the 3rd wheel but jammed between them before completing its action.  Closer examination of the maintaining lever showed that it had been tightened on its shaft by welding its boss to the shaft, unfortunately in the wrong position. I had to cut lever from its boss and braze it on again in the correct position.  When this was done the lever worked correctly with its resting place at the bottom of its travel, and raised up until it reached the underside of the stop, which it had been resting on top of, to activate it.

After repair

Views of the front and rear of the frame.  The going train is on the right. The strike train was not touched except to leave it greased to protect it from further decay. Note the maintaining power lever is at rest in its lowered position at the right of the frame.

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