Butter churn
A butter churn is an implement for making butter from cream or cultured cream. Mechanical agitation gathers the fat into butter grains, which are separated from the buttermilk. It is not a cream separator: churning makes butter rather than separating cream from milk.
Dasher and rotary churns
A dasher churn commonly has a tall wooden vessel and a shaft with a working head moved up and down. Other churns use a crank. Some rotate the entire container; others have a stationary vessel and internal paddles. The exterior shape alone therefore does not explain how the mechanism operated.
As a rural antique
Examine the lid, dasher or crank, hoops and internal components together. Missing or later adapted parts should be disclosed, since they affect understanding and condition. Wear around a lid opening may be relevant but cannot date the implement by itself. Preserve inscriptions and documented farm provenance. Old surfaces should not automatically be considered suitable for food use.
Sources
Store norske leksikon: Kjerne; Opplysningskontoret for melk og meieriprodukter: Kjerne smør.