Magnum Industrial MI-31550, Operating Manual

9

MAINTENANCE 

MAGNUM INDUSTRIAL 20" HEAVY-DUTY PLANER 

MI-31550 / MI-31552 / MI-31553

REPLACING CUTTERHEAD INSERTS

The 

HELICAL CUTTERHEAD (A)

 has 58 reversible 

CARBIDE 

INSERTS (B)

, installed at the factory. Over time and with 

normal use, these inserts need to be reversed and/or replaced. 
To inspect the inserts for wear, manually turn the cutterhead.

To maintain even wear, always reverse or replace all 58 inserts 
together.

To service the cutterhead, follow these steps:

1.  Using an Allen key, loosen but do not remove the 

NUT 

AND SCREW (D)

. Remove the 

INSERT HOLDER (C)

 and 

INSERT (B)

. See Figure 16.

2.  Clean the 

HOUSING (E)

, 

INSERT HOLDER (C)

 and 

INSERT (B)

 with lacquer thinner and a small brush. See 

Figure 16.

3.  Reverse or replace the 

INSERT

 and reinstall with the 

INSERT HOLDER

 into the slot, then install the 

NUT AND 

SCREW

 but do not tighten them yet.

4.  Center the 

INSERT HOLDER (C)

 with the flat edge of the 

NUT

 and fully tighten the 

NUT AND SCREW

. See Figure 

17.

5.  Follow steps 1 to 4 with the remaining inserts.

The 

NUTS AND SCREWS (D)

 that secure the 

INSERT 

HOLDERS

 and 

INSERTS

 in the cutterhead do not have to be 

removed when reversing or replacing the 

INSERTS

.

If the 

NUTS AND SCREWS

 are removed, follow these steps to 

ensure the chip breakers are secured at the same height:

1.  Place the screw in the threaded hole and the nut on the 

screw. Don't tighten yet.

2.  While holding the nut, tighten the screw. This will tighten 

both the screw and nut simultaneously

3.  Do not thread the nut onto the screw before tightening 

the screw into the threaded hole in the cutter head.

WARNING!

Before making any adjustments, ensure the power switch is OFF and the power cord is unplugged

FIGURES 15 and 16: REPLACING CARBIDE INSERTS

FIGURE 17: REPLACING CARBIDE INSERTS

16

17

FIGURE 18: REPLACING CARBIDE INSERTS

18

15