I finished the clock and it is a beauty. The weight shell is currently printing and I don't have BBs yet, so it's being powered by a grocery bag filled with cans of beans.
It's on the 10 day gears, and it needs about 10 or 11 pounds to run reliably, so I think there's some friction I need to try to eliminate. My plan is to take it apart and look for any rough spots, hollow out the arbor holes a little more, maybe reprint the two gears that have elephant's foot (escapement and hour hand gear), dry lube the arbors, and double check that the pendulum bearing friction isn't too bad. If you have any other suggestions for reducing friction, that'd be great.
I have a couple other questions. The curved part on the left of the back frame is where the winding handle gets stored, right?
How hard would it be to add a second hand? Would it take a major redesign of the clock? I suppose it would need to be a deeper clock to make room for a couple more gears.
Would it be possible to make half the period of the pendulum be exactly one second? So tick-tock would be two seconds? It seems like that could work with a longer pendulum and a different gear ratio.
Thanks, Steve, for taking an obviously huge amount of care in designing this clock and creating clear instructions that cover basically every aspect that is needed in assembly.
I made some holiday hands for the clock.
Glad you got it working.
Anything dense can be used to fill the shell. In the US, these are the cheapest BBs I have ever found. They get crummy reviews as BBs but work great as dead weight. Each jar of 6000 weighs about 4.5 pounds. https://www.amazon.com/dp/B000HKKY7M
Pennies are a good alternative. They might even be cheaper per pound than the BBs. Even better if you bother sorting out the pre-1982 pennies at 3.1 grams each compared to the newer zinc core pennies at 2.5 grams each.
Looking good. The grocery bag has some nice complementary colors as well. :) The gears have plenty of backlash so they should be mostly tolerant of a bit of elephant's foot. Maybe clean up the escapement since it is the most sensitive.
I used white lithium grease on the pinions to help reduce friction. A thin layer was added to the pinions and it works its way into the large gears. A few drops of food coloring was added to match the gears. It takes a while to mix water based food coloring into the grease, but it does help hide the color. It has been running at least 6 months with no degradation. PLA seems to be fairly tolerant of anything I have added to it.
Remove the pallet and let the gears free-spin a few times to wear them in. It might only need a pound or two for them to spin. It may take an hour or so for the weight to run down depending on how much weight you use.
Yes, the hook on the left side can be used to store the winding key.
I may never design a clock with a 2 second full period. The 39" long pendulum looks out of place on anything except a large grandfather clock. Retrofitting a second hand into any of my older clocks is not easy. The escapement rotates backwards and the periods are all over the place, like 0.658 seconds. It basically becomes a complete re-design to make it work properly.
I am working on a clock with a 1 second full period (1/2 second in each direction). It does have a properly integrated second hand. And an electric rewind that should last around 6 months per set of batteries. The early prototype can be seen here https://youtu.be/i7kuVZNyTLY