They did not make pellets out of the soybeans. They heated the soybeans to break the protein down so cattle/hogs can digest it. They used the pressure created by the taper screws and then extruded the soybeans out the mold/head. They came out and where kind of a crumble not a true pellet. They took a good 75 horse tractor to even get anything done. 90-100 was better.
The extruded soybeans are a good protein source. I like the end product better than roasted soybeans. It would mix better in your feed.
They where high maintenance. The screws, barrels and head plate would wear out fairly quickly.