DeWalt DW735 Guide D'utilisation page 11

If your material is only slightly twisted:
Plane both sides alternating from one to the other until the desired
thickness is reached.
TO PLANE CUPPED WOOD (FIG. 12)
To obtain the best possible results with cupped wood:
Rip the material down the middle
and plane it as two separate pieces.
Ripping the material reduces the
severity of the cup and allows the
machine to deliver better results.
Understand that you will have to
remove more material on cupped wood to achieve the desired
thickness than you would on a normal board.
If ripping the material is not an option:
Plane one side of the material until flat, then plane the opposite side
until it is also flat.
NOTE: Do not flip the board back and forth between each pass as
recommended by the general planing directions.
TO PLANE BOWED WOOD (FIG. 13)
The feed rollers and cutter head in your planer will push the bow
out of the material as it feeds. However, when the material exits the
planer, the pressure of the rollers and cutter head will release allowing
the wood to spring back into a bowed formation. To properly remove
the bow, use a jointer.
FIG.13
BOWED WOOD WILL BE
FLATTENED BY FEED ROLLERS
AND CUTTER HEAD...
TOP FLAT
FIG.12
BOTTOM FLAT
... BUT BOW WILL RETURN
AFTER WOOD IS PLANED
9
Changing the Planer Knives
WARNING: To reduce the risk of serious personal injury,
disconnect the planer from the power source before attempting
to change or access the knives. An accidental start-up can cause
injury.
TO CHANGE PLANER KNIVES (FIG. 14–19)
1. Use the T-wrench to remove the four screws in the top of the
planer.
2. Lift the top off (Fig. 14) and place it aside.
3. Remove the three wing nuts that seal the dust shroud over the
cutter head.
4. Rotate the dust shroud up so the round connection that locks
onto the fan housing is in the open position (Fig. 15).
FIG. 14
5. Push the dust shroud to the left so it disengages from the fan
housing.
6. Take the dust shroud out of the unit (Fig. 16) and set it aside.
FIG. 15