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Small pendulum clock help

Hi, steve! It's John again! I was almost done printing the small pendulum clock from myminifactory and was having some problems with the fitting of the gears on the arbors. To clarify, I am having issues with gear7-24 and gear7-48, the rachet. My 2.15" 1/8" stainless steel tube is not fitting inside the gears so I was planning on slightly increasing the width of the hole but was wondering if the gears, or a single gear, are supposed to fit tight or be loose on the tube. If it is supposed to be loose or tight, does that apply to other gears as well?

18 comments

18 Comments

Steve

Jun 06, 2022

Lead is getting harder to find because of the toxic properties.

My favorite material has become copper coated steel BBs. The weight shell only needs to be around 50% larger than a lead filled shell. Here is the cheapest I can find.

https://www.amazon.com/Crosman-Copperhead-Copper-Coated-Bottle/dp/B000HKKY7M

Steel slingshot ammo might have very similar density.

Steve

Jun 09, 2022

Replying to

@John R Getting the gears to spin all the way down with 1/2 lb is good. This test might not show a rough spot in the gears since they are spinning quickly and might have enough momentum to jump over the rough spots. Try stopping the escapement at any random location and it should start spinning quickly from a resting position. Do this at every escapement tooth position. This is what the escapement will need to do during every swing of the pendulum. And it needs to be quick to advance to the next position before the pendulum swings. It might take 1 lb of weight on the string to spin the escapement quickly.

Put the clock back together and manually move the pendulum back and forth. The escapement should tick and tock at equal left and right amplitudes. Check this for an entire rotation of the escapement.

A few other random thoughts:

If the frame is sagging, the escapement might spin with 1 lb but pinch the arbors with 9 lb. Adjust the hanging hook and possibly shim the lower standoffs so they are flush to the wall.

Make sure the pendulum and pallet are 100% rigidly connected to each other. If there is slop in one of the shaft collar connections, then the pendulum loses a LOT of energy. The escapement only pushes the pallet during about 3 degrees of travel. When the pallet is being pushed, the pendulum must also get pushed for the clock to operate properly. If there is 1 degree of slop between the pallet and the pendulum, then the pendulum will only be pushed for 2 degrees instead of the target of 3 degrees and the clock would need 50% more drive weight to be functional. Use glue around the shaft collars to make sure they are firmly held in place. Obviously, keep the glue away from the threads. It also helps to replace the tiny set screws with longer screws. They are probably 4-40 screws that are common in the US.