Bob Weight for a German Box Wall clock

Posted: Fri Aug 05, 2011 8:38 pm     Post subject: Bob Weight for a German Box Wall clock

The German box wall clock that I am restoring had most of its mechanical parts when I got it - except for the pendulum. A stamp on the back plate indicates that the pendulum should be 46cm in length. From what I have seen in pictures of similar styled clocks, I have started making a replacement pendulum from a strip of oak and brass welding rods and other brass pieces required for the fine adjustment. I have found a small disk of solid brass about 6 cm (2 3/8 inches) in diameter which I would like to use for the bob. The bob and adjustment assembly at the end of the oak arm currently weighs about 120g (or roughly 4 oz). I have seen recommendations of 8 oz but it was not clear that it would be for this style of clock.

The pendulum is suspended by a spring loaded swing arm so it is not hanging of the pivot.

I have not tried the constructed pendulum yet (still working on the mechanism) but just want to get feel for what I should be aiming for to get a reliable setup going. Does any one have a figure for the typical bob weight for this style of clock?

Posted: Tue Aug 09, 2011 1:07 pm     Post subject:

picking out words from your post i would gues whay u have is a edwardian wall oak striking clock with a pendulum about 14 -20 inches long.
the bob on these are usually hollow brass with the wooden rod going through the middle and a steel threaded rod on the bottom.

the bob diameter is usually roughly 4 inches

Posted: Wed Aug 10, 2011 12:50 am     Post subject:

Hi Clockfxr, Yes, is is an oak wall striking clock with three rods (a pair and a single). Not sure about the Edwardian part but you should know better than myself. The fact that the pendulum length is specified on the back plate in metric units made me think that it originated from Europe (i.e Germany) rather than the UK or US. However, it could be that only the mechanism came from Europe.

I fitted the clock face temporary just to take this picture. I should adjust it to center it.



The bottom glass is my replacement of the original beveled "lead glass" after I had given up (13 years ago and before Google ) on finding a bevel glass supplier that could cut pieces small enough to replace the broken pieces. Google has since found a supplier and I will restore the original glory once the mechanism is sorted out.

The dark stripes in the wood is due to the use of a black polish to treat furniture at the time. When I got it the wood was a dull dusty black color and the veneer around the face plate in a bad shape of delamination, splintering off at the edges.