Those are objects from the Roman Empire. About 130 have been found in total.
They are typically made of brass and fit in the hand but can vary from 35 grams to a kilo. Each side has holes of different sizes with rings around them. On each corner you will find a sphere protruding.
But there are three things you won't find.
- you won't find them in or near the capital. They are found all over the European part of the empire including Britain, but never once in the Near East or African portions of the empire and also never in what we call Italy today.
- you won't find why they exist. There is no known use for them that survives scrutiny. But you will find lots of speculation.
- you won't find any markings. No labeles, no symbols, no gauges, or numbers. Just holes with rings.
Are they part of a mystery colt, some rather expensive game piece, blacksmith training? No one knows.
Find a 3D print file and make one yourself and ponder it for a while. Or draw one. I haven't found any woodworking plans. Maybe I could fix that.
Micron, A5.
That's where my mind went too. Just imaging how they got the balls on there. Was it one piece? Many pieces? How did they keep it from warping? How many attempts would it take? Crazy to think it was made at all
Its likely that they were sheets of brass cut, folded and soldered / brazed together, then shaped and cleaned up afterwards with files. Clickspring has videos going over some of the techniques likely used for constructing the Antikythera mechanism. They could also be cast. Ive seen examples which indicate both techniques.
One theory on the dodecahedrons ( and occasional icosahedron) was that it is of Celtic origin rather than roman, as the finding distribution more closely matches their regions, and the dodecahedrkn and icosahedron were considered holy symbols, akin to the cross to christians. This may explain their presence in army camps, where knitting is unlikely. Also there is little to no standardization on sizing or markings to indicate hole size, which makes it less likely to be for knitting or glove making.