Sterling SXS Series - Manual (Page 44)

BJ5-620 Maintenance 44 of 73
Working on the Cutting Knives
Correctly setting and mounting the cutting knives is important when working with
shredders to ensure efficient and economic function.
Replacing and Checking the Cutting Knife Mountings
Certain machine parts are subject to stress during operation as a result of vibrations that
can lead to loosening of the screw connections. It is absolutely necessary to check the
cutter and bed knife mounting screws in accordance with the maintenance plan.
1. Tighten the mounting screws on the cutters and bed knives using a torque
wrench (check required torque for the screw size). The required torque
for the knife fixing bolts is 355 Nm.
NOTE: You can find out the required torque from the following table. Tightening
capacity decreases for screws when loosened and tightened again several times.
New screws of the same material quality must replace the cutting knife
mounting screws after they have been loosened and tightened several times.
Checking the Condition of the Cutters
WARNING! Danger of cutting caused by sharp knives at all times—even when rotor is at
standstill. Serious Injury especially to the hands and fingers can occur. Wear protective
gloves!
The cutting knives become blunt after a certain number of operation hours; they should
be checked regularly. Using blunt knives can affect the efficiency and performance of
the machine in the following ways:
• Decreased shredding capacity.
• Increased current consumption of the drive motor.
• Inexact cut.
• Overheating of the shredded material.
Torque
Bolt type Grade 8.8 Grade 10.9 Grade 12.9
Nm lbf ft Nm lbf ft Nm lbf ft
M8 25 18.4 35 25.8 41 30.2
M10 49 36.1 69 50.9 83 61.2
M12 86 63.4 120 88.5 145 106
M16 210 154 295 217 355 261
M20 410 302 580 428 690 508
M24 710 523 1000 737 1200 885