The clearance between the end of the screw and the press head itself is one common adjustment, though not an adjustment available on all presses. As this clearance is made smaller, the force needed to push the seeds through the press increases, creating a greater pressure overall on the oil/meal mixture. Too much pressure, though, and the oil press will no longer allow the meal to pass through effectively blocking the meal flow and stopping the flow of material through the press. Too large a distance and the meal will pass through easily, leaving a large amount of oil in the meal. Finding the correct setting is a balance between the meal passing reliably through the press and extracting the maximum amount of oil while doing so.
 
On a Kern Kraft press, this setting is changed by turning the pressing head in or out. As the head is turned, the threading either increases or decreases the clearance between the end of the screw and the press head. Even a small adjustment (1/16 of a turn) can change the press from being productive to being plugged. Once an adjustment is made it can usually be left for the duration of the pressing of that seed. It is not a set-ting that needs to be altered continuously.
 
Turning the press head out to in-crease clearance looks like an easy process, and usually it is. If the ma-chine has been run for a long period of time, or the heating element has been used on the barrel and head while pressing then turning the press head may be difficult. Turning the press head in can be a trying proposition because meal is already packed into the space between the end of the screw and the presshead. Reducing this clearance means squeezing this material tighter, and that’s not always easy to do. Removing the press head and clearing the material may be the only way to relieve this pressure enough to be able to turn the press head in.