Here’s a more detailed idea of the Sampo, from Rune X of the Kalevala:

On the third night Ilmarinen,

Bending low to view his metals,

On the bottom of the furnace,

Sees the magic Sampo rising,

Sees the lid in many colors.

Quick the artist of Wainola

Forges with the tongs and anvil,

Knocking with a heavy hammer,

Forges skilfully the Sampo;

On one side the flour is grinding,

On another salt is making,

On a third is money forging,

And the lid is many-colored.

Well the Sampo grinds when finished,

To and fro the lid in rocking,

Grinds one measure at the day-break,

Grinds a measure fit for eating,

Grinds a second for the market,

Grinds a third one for the store-house.