Timer is finished!

I made a number of finishing touches to the gravity escapement timer.  It now runs reliably!
First, I turned a thicker barrel on the lathe

Using a square file, I cut a keyway to engage with the metal teeth on the existing barrel.

Here's the finished barrel, ready for installation...

...and here it is installed.

Many of the wheels weren't running smoothly.  To find where to file, I used a pencil to mark the pinion teeth...

... which transfered to the driving wheel.  This could be filed down as needed.

Quite accidentally, I made the pinion teeth an integer multiple of their driving wheel teeth.  This made debugging easier!  Because I found certain pairs of teeth consistently binding.  I marked them like so

which allowed me to track down the problems! 
 I made a 4 oz pendulum bob from two halves that friction fit to the pendulum. 

The excess screws are for weight!

 
It's worth noting setting that a gravity escapement in beat is quite a bit more delicate than I expected.  Here's a picture of the timer in action...

And a link to a video!