The LEDs are 1/8th inch in diameter (T1) or actually 3mm since they come from asia. They use a world standard, we do not.
The Signal masts are made of 3/8" x 3/8" basswood.
I clamp the stick before drilling the holes, 1/8" holes are perfect, but recently I have been making them just a little wider. Clamping the stick helps prevent it spliting when you drill it.
I “paint” the stick with a majyck marker. I leave the bottom unpainted since it will go into the table top anyway, and it keeps the ink off of my nice furry paws.
LION used LEDs from All Electronics and have been pleased with these for many years. You had to use a motor tool to sand down the rims so that they fit correctly into the mast. More lately I have been using Christmas lights from Walmart and or Menards. The ones with the little plastic dodads on them have the smaller T1 lamps on the inside. You have to fight to get the dodad off but then you can extract the LED. They are much brighter and far more vivid that the normal ones. They have the inverted cone top that spreads the light rather than focussing it down the line as you would expect. But the colors are so much better…
The cathode side (-) are bent downand soldered together…
Thus it takes four conductors. I like to purt the 1K ohm resistor on the common side. It is low enough so that it disappears into hole in the table. I always put the resistor here, lest I forget it and burn out the LEDs.
Black modeling clay is used to cover the back to hide the wires and to prevent light escape.