Magnum Industrial MI-31550, Operating Manual

13

MAINTENANCE 

MAGNUM INDUSTRIAL 20" HEAVY-DUTY PLANER 

MI-31550 / MI-31552 / MI-31553

WARNING!

Before performing any maintenance, ensure the power switch is OFF and the power cord is unplugged

ADJUSTING BELT TENSION

Inspect the belts after every 100 hours of use. To adjust belt 
tension, first remove the upper and lower panels on the left 
side of the planer (refer to the instructions on page 12). Check 
the belt tension by pushing the belt with your finger. The belt 
should not move more than 1/2". If the belt is too slack, adjust 
the tension: 

1.  Open the motor access panel. Loosen the two 

JAM NUTS 

(A)

 and then raise or lower the two 

NUTS (B)

 with a 19 

mm wrench to increase or decrease belt tension. See 
Figure 30.

2.  Retighten the 

JAM NUTS (A)

 against the motor mounting 

plate. 

3.  Close the motor access door.

FIGURE 30: ALIGNING DRIVE PULLEYS

FIGURES 31 and 32: BELT INSTALLATION

30

31

CHANGING BELTS

If the belts show signs of wear, such as cracks or frays, replace them as soon as 
possible.

1.  Remove the 

NUTS (B)

.

2.  Position a piece of wood under the motor base. See Figure 31.

3.  Step on the wood to pivot the motor up, and then remove the belts from the 

upper pulley.

4.  Install the new belts, starting with the lower pulley. Reinstall the 

NUTS (B)

.

5.  Adjust the tension (refer to the instructions in the section above).

6.  Reinstall the left panels and close the motor access door before starting the 

machine.

32