They might be machined. What are they made of, some kind of graphite? It must be softer than bronze or copper alloys so it must not be that hard to make a hole and insert a blinking red LED. Also someone mentioned this find in the Mandalorian Reference Thread, apparently someone on reddit IDed it casue he works with those: maybe more info can be found through that source.
Electric motor carbon brushes as usually very small, like 1/2 the size of a postage stamp. Even for a big motor they aren't very big, smaller that the tracking fob. I can see the similar shape but I can't imagine that that prop was made from a solid metal block.
Now might be a good time to settle on a particular part of the build... It should be possible to replicate the function on the show and have them all beep in synchronization when near each other. sticking a cheap wireless module should work. the NRF24L01 would be a good one to look at. It's tiny and cheap. (not sure about the sound effect, though)
Just thought I'd leave my own thoughts on this subject after someone brought these up in another thread -
My guess on the size prior to these being found was roughly 1.5" x 2.5" with some kind of indicator light (5/16th?) Then someone posted about "Helwig Carbon" these seem to be roughly 1.5" x 2.25" x .5" (.375" seems more common than .5", but I think that's too small) on average with a few differences here and there. There's a lot to look through online, but this is the closest I found so far, and at a better price tag than that one on amazon!
Given all that, I think they're custom for the show, since none of the brushes I have come across have that "groove" below the light and a few details with the metal bit seem to not be found on any real one either. Also housing the electronics for the blinking light seems like it would be a problem. But if we are going to get some info from an insider, that'll hopefully put all this guesswork to rest!
Yea, this is a repeat discussion on some of the facebook groups, but people need to research this because there's functionally no way they actually used these for the actual props due to the fact these things are solid, brittle bricks of material that are meant to get worn away in a motor. While the overall prop design is uncanny, the props themselves very likely were scratch built and inspired by the motor brush