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Edited: Oct 22, 2022

Finished the large Easy Build Clock (Minus weight shell)

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.

11 comments

11 Comments

wagnmkr

Aug 30

That is a very interesting colour scheme on your clock. It looks like a good runner.

greenxblue

Dec 14, 2022

I made some holiday hands for the clock.

Steve

Dec 14, 2022

Replying to

Those are super cool looking. Great job.

Steve

Oct 24, 2022

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.

Steve

Oct 22, 2022

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

Steve

Oct 22, 2022

Replying to

I suppose dry lube should be used first and only lithium grease as a last resort.

The clock I added grease to was completely stalled by the "sticky gear" issue. The solution turned out to be the helical gear change, but so far there does not appear to be any side effects from the grease. It was a very thin coat of grease and it might not be attracting much dust.

Even the escapement is not showing any wear and it is the fastest moving part with deliberate sliding action. I have no doubt that it will last at least 5-10 years. If it does wear out, then it is easy to print a replacement part. :)

greenxblue

Oct 22, 2022

Replying to

Ok, thanks a lot. Yes, it is nice to be able to easily print replacements. I'll let you know how my efforts to reduce friction go.

greenxblue

Oct 24, 2022

Replying to

I'm not sure what exactly helped with the friction, possibly just letting it run for a few hours with no pallet like you said. I also sanded the rods and enlarged the holes. I noticed the hour hand gear was pretty tight in the front frame so I sanded that down, although I'm not sure if that does much since the hour hand moves so slow.

But I had it running with about 1.7 pounds no pallet, about 5.3 pounds fully assembled, and it's currently running for the past few hours at about 7.2 pounds.

For the weight shell, I decided to try using coins since I had about 4 pounds of change. I went to the bank and got $10 more in pennies. I was able to squeeze about two hundred combined quarters and nickels rolled up, one hundred loose dimes, and seven hundred loose pennies into the 3.2 inch weight shell, no extension.

My thinking was that pennies and BBs are comparable in price. But also pennies are technically free, since you always still have that money if you need it. And I thought it might be possible to get even more mass into the shell if the pennies were in rolls, since packing density of cylinders is up to 90% as opposed to sphere packing density which is max 70%. I was not able to really arrange the rolls neatly in the shell though, so I put a couple rolls in the bottom, then poured loose pennies on top. Shaking the shell packed the loose coins down a little bit as they spontaneously formed little cylinders.

Maybe at some point I'll try to remake the weight shell to be more similar to the pendulum, where it has premade cylindrical slots for pennies, but with thin walls, and the areas left over between the cylinders can be filled with something else, like BBs or sand.

It's ticking away. I'll try to tune the speed of the pendulum over the next few days.