I made considerable progress on my timer over the past two weekends. I started with a pile of parts (after sanding)...
Since the design phase, I had left the spacing between the two plates as a yet-to-be determined variable. The key distance was the winding barrel, which had to rotate freely around the main wheel's arbor and engage with the ratchet and click assembly. I wasn't quite sure how much room I'd need, so I built the winding barrel first.
The winding barrel is hollow, and has two transverse pins to anchor the winding ribbon. First, I turned the outside of the winding barrel from 1/4" brass rod. Notice the thicker end (left) to receive the ratchet wheel.
I center drilled the assembled winding barrel in the lathe.
After it was drilled, it was fit friction-tight into the ratchet wheel.
Now that I knew the length of the winding barrel, I could estimate the distance between plates. Here are the two standoffs that hold the plates in place.
Now, on to the escape wheel. Again, it was important to get the size of the escape wheel before making its arbor. The escape wheel consists of two three-toothed wheels, held part by three brass pins. Here are the pins, turned from 1/8" brass rod.
The second weekend started with making lots of pins... There are (top to bottom) 2x locking pins, 2x pendulum crutch pins, 2x gravity arm pivots, and a pendulum support.
Gary Mahoney's clock:
I slit my pendulum support rod with a jeweler's saw, filed two flats, and then drilled to receive a screw.
The key issues seem to be that
- The escape pinion binds occasionally, stopping the clock
- The escape wheel occasionally skips, in which it slips past its locking pin rather than being captured. This is kind of catastrophic since the pendulum receives an out-of-phase impulse; sometimes it can recover, sometimes it can't. I think the cause is the gravity arms slipping along their pivots.
- Cap off the ends of the gravity arm pivots. The arms tend to slip around and off the pivots
- Fix the gravity arm pivots by either remaking them (preferable) or making custom washers so that they keep the gravity arms the correct distance away from the outer plate.
- Fix the depthing of the escape pinion
- Fabricate a pendulum bob. The current bob is attached with a rubber band
- Replace the pendulum pivot with something a bit stiffer than paper -- the pendulum wobbles axially too much.
- Fashion a drive weight and winding pull
- Fashion a hand for the main wheel arbor
- Further debugging until it runs reliably