Escapement

I removed the DUFA's hands and dial. Which leaves the front plate showing the motion works (the parts that turn the hands). You can see that this movement also uses a  rack & snail  for its striking. When the rack is activated it starts things turning in the back of the clock. Here is a rear view of the movement showing the hammers on the strike. They are attached to arbors that turn as part of the strike. When the clock strikes those arbors turn, lifting the hammers, and then they release the lift such that the hammers drop and strike the gong rods in the case. Here you can see how the hammers are all connected to a cylinder that is screwed onto an arbor. The left set has been removed from their arbor in the photo below. So... How does that lifting of the hammers actually happen? The rack and snail determines how many times the clock should strike.  When the rack and snail are activated the strike train turns the pin wheel (seen below) counterclockwise. As it the pin...

The DUFA is the first tall case / grandfather clock I've ever owned much less done a full breakdown, clean, repair and reassembly. It's exciting! While I will detail a bit of the disassembly of its movement, I'm going to focus for a bit on the amazing strike of this DUFA. Beyond its beautiful tone, the mechanics of the strike really tickled the gray cells of this engineer. It turned out to be quite a learning journey. Some clocks strike the hours with a single beat, repeated to count each hour. The  dog clock  does this. A single hammer strikes its bell once for 1pm, twice for 2pm, etc. A very common and lovely-sounding design of many a French clock. Our DUFA strike is what is called a Bim Bam  or Normandy style. The Brits call them Ting Tang.  Think "ding dong" like a doorbell. Bim Bams count the hour by striking two different tones in pairs for each hour. Ding dong for 1pm.  Ding dong, ding dong for 2pm.  Etc. The DUFA box clock also has a Bim Bam strike,...

When we last reviewed our DUFA friend I noted that the movement looked to be in good shape and I was about to embark on a cleaning. A practical approach to cleaning starts with a disassembly and simultaneous deep inspection. Diving in... It appears that someone tried to make a repair on the movement's suspension spring. You can see the suspension spring glittering above on the upper right.  Likely the suspension spring broke by some form of rough handling of the pendulum. The home-brew repair effort speaks to the repair person's inexperience with mechanical clocks. Not to sound smug... it's just that the results speak for themselves to the trained eye. Suspension springs use very thin, highly-flexible "wires" (metal strips), often in pairs. The thinness and flexibility of the suspension wires is key.  A pendulum must oscillate and be able to receive power from the escapement easily. In most clocks the performance of a pendulum is greatly enhanced by the use of a ...