varx/socialFound a neat site that walks you through disassembling your electric toothbrush and replacing the battery. Usually requires some soldering, but... very cool. (They're funded by selling replacement batteries!)
While disassembling my toothbrush, I came across an oddity. What are these little gray cylinders?
They're held loosely captive in a pocket of the plastic, not touching any other component. They're lightweight, rigid, non-magnetic, and maybe composed of something granular.
What the heck?
[EDIT: See rest of thread for possible answer!]
C.Do their exposed ends touch something metal when the case is reassembled?
Because they look like they could be motor brushes, which carry electricity down onto the contacts on the motor rotor. Those are made of graphite and a secret blend of herbs and spices, and definitely qualify as "kinda granular". Usually the electricity gets to the brushes via a little spring they're mounted on, which pushes them against the rotor, but it can be done other ways too.
@cazabon Nope, they only touch plastic. Here are two more photos, one of the entire core of the toothbrush (one cylinder removed and sitting on the desk) and one of a closeup of the recess where it was sitting. The wall of the recess that you can't see here is just solid plastic.
When assembled, the wall of the shell might be kind of close, but is also just white plastic in that area.
Hmm. So the rough edge on the mystery cylinder shown in your original post is where the plastic clip holds the cylinder in. Does the other end of the cylinder - or its side(s) - show signs of wear?
I'm wondering if they are actually just compressed graphite, as a dry lubricant for the motor/transmission shaft.
I've got what looks like the same brand of toothbrush. Now you make me want to take mine apart 🧰 🔧 🔨 ...
@cazabon One or both have been in and out of the recesses, so I don't know which end was out. Both have at least one end that looks very clean and crisp.
But they don't appear to be graphite, no. I can't write with them, and they're gritty and make a (small) harsh scraping noise against metal.
They're also below the motor, so anything that falls off of them would go into the battery compartment.
Okay, that's not it, then.
Well, I'm down to "CIA tracking device" and "alien abduction locator beacon" as my next-best guesses... 👽 👾 🕴️ 😎
I'd be interested in what you find out!
@cazabon Yet another mystery that could perhaps be solved more easily if only I had a portable X-ray fluorescence analyzer!
*checks prices on e-bay*
Yet another day I am reminded of why I do not own a portable XRF analyzer!