AEC 1426-i Twin-Shear Granulator - Manual (Page 21)

1426-i Granulator Chapter 5: Maintenance 20 of 37
5-4 Replacing and Adjusting the Knives
During use, the clearance between the rotor knives and the bed knives will increase due to
wear. This is a normal condition that requires re-setting this clearance once or twice before it
is necessary to remove the knives for regrinding. Check the knives weekly for wear,
clearance, exposure, and screw tightness.
When new knives are fitted to the machine, adjustment after eight hours of running time may
be required.
Before assembling a new or reground set of knives, make sure the knife seats and mounting
holes are clean. Do not use grease or oil on screws or tapped holes when assembling the
knives.
Knives must be replaced in complete sets, otherwise it will not be possible to obtain even
clearance between the rotor knives and bed knives.
WARNING! Before applying a wrench to any knife bolt, be certain that the rotor is
blocked to prevent rotation. One such method is to use a block of wood at
least 1 1/2” thick between a knife and a fixed portion of the frame.
Rotor Knives
We recommend that the rotor knife screws be replaced with new screws every sixth knife
change to reduce the risk of screw failure due to overstretching. Screws must be replaced
with the type specified in the spare parts list. Use the following procedure to replace or adjust
the rotor knives:
Caution! Rotor knives should be changed one seat at a time to prevent rotor from
being rotated in an out-of-balance condition.
1. Access the cutting chamber as directed in Section 3-4 on page 14.
2. Remove the bed knife shield screws and lift off the bed knife shield.
3. Remove the screws holding the bed knives, and remove the bed knives.
4. Remove the screws holding the knives to the rotor and remove the rotor knives.
5. Thoroughly clean the knife seats, and replace the knives.
6. Lightly tighten the screws and check that a 0.04 mm (0.0015”) feeler gauge will not
pass between the back of the knife and the knife seat. Tap the knife gently with a
rawhide hammer if necessary to close the gap.
7. Tighten the screws evenly and torque the high tensile 16 mm screws to 266 Nm (16
ft. lbs.)
Note: Bolt threads should not be oiled. Wipe thread with and oil-dampened cloth.
8. Re-check the gap between the back of the knife and the knife seat. If necessary,
readjust the knife.
9. Adjust the clearance between the bed knives and rotor knives. (See “Bed Knives” on
page 21.)