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SCREW REPLACEMENT
When reinstalling a screw, the screw must be pulled in until the step in the shaft
seats against the thrust bearing of the gearbox. This will position the flights of the
screw so as not to hit the resistor teeth. Be careful when guiding this step in the
shaft through the shaft seals.
During re-assembly of a keyed shaft, be sure to apply Never-Seez or Anti Seize to
the portion of the screw shaft that goes into the gearbox.
When pulling a screw into the press it may become necessary to use a long
allthread rod (English threads). This rod is screwed into the threaded hole on the
end of the screw. The screw is slid into the press far enough that the allthread rod
goes through the hollow bore of the gearbox. A large washer is slid along the
allthread rod to form a brace against the gearbox. Running a nut on the rod,
against this large washer, will pull the screw into the gearbox.
There are two ways to avoid excessive rubbing between a new screw and the
screen: Either a shim can be placed in the clamshell opening at the resistor bar, or
the interference can be ground off the edge of the screw. To eliminate the high
spots, coat the edge of the screw with Prussian Blue, tighten the assembly, turn the
screw, remove the screen, and then grind the screw where interference has
occurred.
GEARBOX BASICS
The smaller Series KP presses use Nord hollow bore gearboxes, with a C-face
mounted motor. In order to facilitate maintenance, the largest KP presses use foot-
mounted gearboxes, with a male output shaft that is coupled to the shaft of the
screw.
Gearboxes are rated, and sold, by their torque rating. The manufacturers generally
offer their designs in progressively larger sized castings, or boxes. The larger the
box, the larger the torque rating. Each box size will be available with different gear
ratios. In order to keep the torque fairly constant, larger horsepower motors are
used with the high speed boxes. Similarly, reduced horsepower motors must be
used when a low output speed is selected.
Screw presses are designed around the size of the gearbox that is selected.
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