I liked the idea of the abacus for counting hits during combat so I built one for my gaming table.
I got the beads from Michael’s a craft store here in Canada, and a brass rod from Home Depot. I did have the drill out the beads a little as they were a bit too snug on the rod. I had the rod first. I have mounted it on a some 3/4 inch plywood that I cut down, and I made the attachment points on the computer and 3D printed them. At first I just used some wood blocks until I got the idea to 3D print the attachment points.
I painted the beads grey, green, and red in the same style as the chips from the game. 1, 3, 5. this makes counting that much easier from across the table.
All in all a very useful tool/customization. I have 15 per side, and only have troubles when doing the massive battles in Russia.
I have attached the STL files that I made for the 3D prints. They will work with a rod dia of 3/16 of an inch.
Hope this helps.
Buran

Abacus Plates.zip