Whatever the reason Sam went to Minneapolis -- maybe to visit his father who was widowed and liviing alone there or maybe specifically to find something to add to the farm work -- it was a turning point in the family history. Kovar machinery, for the years the Strachans represented it, lifted them into the profit zone.
Quack grass was a deep-rooted rhizomatous pest for fields. The Kovar Kultivator was able to hook onto those long stolons and roots and drag them out of the ground, to lie on the surface and die in the sun.
This is a smaller one-section Kovar and I believe that's Bruce behind the team.
The machine parts were sent up from Minneapolis to avoid a higher tariff for the whole machine. The Strachans assembled them, marketed and delivered them. Then the tariffs were reorganized and the project became economically unviable, but by that time the Strachans had left Swan River.