Violin sound pin setting tool

The sound pin in Zachary's violin was inadvertently knocked over.  There's a tool for fixing this problem, and it is not expensive.  However, it was also not available on short notice, so I made one.

The tool is a 1/8" steel rod set in a handle of rosewood.  To make the tip, I hammered the end of the rod into a spade shape, hardened it, and then ground it to a sharp flat blade.  I then bent the rod to fit the shape of the violin, which is a standard 4/4 size.  Afterwards, I polished the rod, oiled it slightly, and set it in the handle.  The handle was a short segment of a hard rose cane I had taken during pruning, and was shaped on the belt sander.

To use the tool, stab the sharp end into the sound pin (grainwise), carefully thread the pin and tool through the F-hole, and then carefully upright the pin just below the treble foot of the bridge. This took me a few tries, but it wasn't too demanding.  Just make sure the bridge is already mostly in place with the strings just barely tightened before you begin, otherwise uprighting the bridge will surely topple the sound pin. 

Clock 4 now runs with intermittent impulsing

"Intermittent" can be a problem, but not in this case!  Based on the numerous power budget calculations I've done, impulsing the pendulum in Clock 4 every minute is too much to ask.  After having gotten the escapement to impulse every period (2 seconds) reliably, with run times around 8 hours, it seemed like the right time to go back to trying to get the intermittent part working again.  Especially, the run times without intermittent escaping were limited by drive cord length -- I had a four fall pulley in place for the clock to run that long. 

Therefore, I added more deep cuts to the count wheel, now five in total.

This means that the escapement should be triggered every 30/5 = 6 pendulum periods, or every 12 seconds.  The pin wheel has 30 pins, so will then have a period of 12 seconds * 30 = 360 seconds = 6 minutes.  The pin wheel is driven through a 1:10 mesh for the drive wheel, so it should make a rotation every hour.  I can therefore drive the minute hand from the drive wheel, although it will run counter clockwise.

With some tuning, the Clock 4 runs with 8 lb of drive weight, directly driving a barrel of 1.2 inches.  The clock's run isn't perfect, as (1) the count wheel double counts immediately following an impulse and (2) sometimes this double-counting skips over an impulse.

But given these issues, Theodore measures the following periods in current configuration:

• 53 seconds for the count wheel

• 4 minutes 24 seconds for pin wheel

Given these measurements the drive barrel will make one rotation about every 44 minutes.  In that time, the weight will have dropped 3.7 inches. 

Thus the power consumed is:

3.7 inches / (12 in/ft)  * 8 lb / (44 min * (60 s/min)) = 9.4 * 10^(-4) ft lb / s = 1.28 mW