There is an unusual feature of the screws in Vincent presses which frequently goes unnoticed.  These are notches ground in the outside diameter of the flights. 

It was California customer, working manure with one of our rental presses, who came up with the idea.  The manure was slimy, and it seemed to blind over the screen of the press.  Little press liquor would come out, the cake came out wet, and the press throughput capacity was low.  This situation was greatly alleviated by adding notches as seen in the photo below.

The basic idea is, during press operation, to have the screw wipe the screen clear of blinding material.  Cutting shallow notches (1/8" wide by 1/8" deep, 1-1/2" apart) in the outer edge of the screw flights best achieves this.  Fibrous material accumulates in the notches and wipes away slimy material which may be blinding the screen.

Typically, notching is done from the B plate to the second resistor tooth. 

Because it never seems to hurt, and sometimes it makes a night & day improvement, notches are a standard feature in all Vincent presses.  The two exceptions are (1) food grade applications where one would not want an accumulation of material as a source of bacterial growth, and (2) plastic film applications where the film can fill the notches and lead to binding in the press.

GRINDING NOTCHES IN THE FLIGHTS