Regulating

Now that I've been running the clock for some time, it looks like it was running consistently fast.  Disassembling the clock and examining, I found that

• The pendulum rod weighed 200g
• The pendulum rod (from arbor center to end) was 43"
• The pendulum bob weighed 100g

Putting this together, the farthest the center of mass could be from the arbor is about 29".  That's far shorter than the nearly 39" it should be.   Tweaking these values a bit, it looked like I needed to reduce the weight of the rod to around 50g and increase the bob weight to over 300g in order to be able to make a band of adjustments around the correct length.

Given that direction, I used a router to grind down the pendulum rod to quite bit thinner.  This took off about 100g, but also made somewhat of a mess.  Fortunately, I could make this the back so it's not so obvious.  I then tapered the rest of the rod using a plane.  In the end, the pendulum rod weighed 60g and is quite delicate.

I also cut two more circles of plywood to add additional weight to the back of the pendulum bob -- now it is 325g.

Given those two changes, I found that the clock had difficulty running.  Earlier calculations suggested that this would happen, because more lifting force needs to be applied at the anchor.  Therefore, I very carefully filed back the anchor teeth on the escapement to reduce the lift.  I may have overdone the exit tooth, but after applying more Slip-It to the gear teeth and pivots, the clock runs. 

After these changes, with the pendulum bob roughly in the middle of its range, the clock actually runs slow by about a minute every hour.  That's a success: I can now adjust both faster and slower as needed.  So now it remains to slowly bring it into regulation over the next few days.