Bim Bam

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, with its lovely Largo gong, which consists of 3 rods and 3 hammers.

Our DUFA tall case clock has a gong with eight rods. The strike utilizes eight hammers divided into 2 pairs, that hit against 2 pairs of 4 rods. Each individual rod is a different length such that each pair of 4 rods forms a different musical chord of a sort.

Here is the gong mounted to the rear panel of the case.

Here is a rear view of the movement. You can see the two pairs of four hammers. 

When slotted into the case that wooden shelf slides in such that the hammers go in first and line up right next to their rod counterparts, the dial of the clock facing outwards.

Here's the movement in the case (without its dial) and you can see the hammers protruding just below the shelf, aligned to the rods.

Yes I've used an "after" shot of the movement after I cleaned and reassembled it. I was testing the alignment of the hammers to the rods post-reassembly.

And a closeup of me checking the spacing on the right side.

When the DUFA strikes, its strike train (a "train" represents all the clock wheels and components to a particular operation of a clock) activates and lifts the four left hammers which then drop and hit the left rods in unison and then the strike train lifts the right four hammers which drop and hit the right rods. The left side rods are a bit shorter than those on the right thus making a higher pitched "ding" than their counterparts "dong".

It is a deep DING DONG that resonates for a long time in the large case of the clock.

It sounds really beautiful.

Your clockmaker also did some research on the gong for this clock. 

I discoursed on this a bit in my DUFA box clock post but I will summarize by saying those Germans loved their gongs back in the day. The NAWCC experts cite the German quote "ein guter Gong verkauft die Uhr" or "a good Gong sells the Clock."

German gongs, like the Largo gong, were often patented/registered. Those registrations were called Deutsche Reich Gebraumeister (or Gebrauchsmuster, or Geschmacks Muster... sheesh). 

Or D.R.G.M.

And so here we have a clue for dating our clock...

And looking up our Geschmacks Muster on the interwebs... 

Our gong was registered in 1929... 

Or was it?

Well, according the NAWCC gurus, "almost all" of the historical DRGM data for the dates between 1891 (when the registrations were established) and 1934 was lost by the German government and therefore most online sources are considered unreliable.

Digging a bit further NAWCC does have some historical DRGM data (of course) that is probably more reliable than the above linked source.

And the NAWCC data says our DUFA DRGM is from 1928.

We'll go with that.

The NAWCC crew also says that given the popularity and rapid registrations of German gongs, factory clocks with those gongs were usually manufactured either within or following the year of a particular gong DRGM date. 

So our DUFA clock itself was likely made in 1928 or 1929 and possibly 1930. 

Give or take.

I haven't even started on the fascinating/challenging guts of the strike.

More to come.