DeWalt DW898 Guide D'utilisation page 5

The tool is factory assembled with the punch oriented forward for
cutting flat and shallow corrugated material.
The head can be aligned in three positions: left, forward, and right
(See Figure 2). To rotate the head, loosen the set screw. Turn the
head in the desired direction. NOTE: Do not rotate the head in a
complete circle as this will change the punch engagement in the die.
Rotate the housing in the head and turn the set screw in until you feel
the set screw engage a recess in the shoe. Tighten the set screw
firmly. Periodically recheck this screw for tightness.
The nibbler head is designed to fit through a 3/4" (19mm) diameter
hole for starting a cut in the middle of the work. Nibbling can be done
in any direction from this hole. A punch width indicator is provided
on the front of the housing to allow users to follow a line closely
(Figure 3).
The bottom of the housing has a .51" (13mm) diameter template
guide to allow for use of templates. See Figures 2 and 3 for template
guide surface. The thickness of the template should be such that the
FIG 2
HEAD
CAM
SHAFT
PUNCH
HOUSING
CONNECTING
ROD BUSHING TEMPLATE
GUIDE
CARRIER
DIE
SHAFT
COVER RING
CAM
HEAD
FIG 3
SHAFT
SET
SCREW
HOUSING
TEMPLATE
PUNCH GUIDE
DIE
COVER
RING
total thickness of the template and workpiece is 13/64" to 1/4" (5 to
6.5mm). The shape of the template must be .1" (2.5mm) away from
the shape to be nibbled. The tool should be guided so that the
outside diameter (.51" or 13mm) of the housing always rests on the
template.
CHANGING PUNCHES
Never cut with a blunt, dull punch. Punches can be sharpened until
they reach a length of 2.72" (69mm). Shorter punches are
unserviceable. To remove the punch, loosen the head set screw
about 4-5 turns (See Figure 2). Slide the housing from the head.
Unscrew the punch from the connecting rod bushing. Punch may be
resharpened carefully on a bench grinder with a fine grit wheel. Be
careful that the punch does not become shorter than the minimum
length. Punches shorter than this will not engage the die sufficiently
and must be replaced. The ground face must be square to the punch
axis. After grinding, carefully stone the ground edges to remove
burrs. Do not round over corners.
REASSEMBLY OF NIBBLER HEAD
Screw the punch fully into the connecting rod bushing. Slide the
housing over the end of the punch and into the head. Turn the
housing to desired cut orientation. Tighten set screw. Next, check
punch engagement.
CHECKING PUNCH ENGAGEMENT
Since the punch length is now changed, the punch engagement may
have to be adjusted. Check punch engagement by placing a flat
blade screwdriver in the cam shaft slot and turning the shaft (See
Figure 2). Punch should dip .020" to .06" (.5 to 1.15mm) into the die
at the full down stroke position. Too much punch dip into the die will
result in a loss of capacity (bottom of punch will not clear die enough
on up stroke.)
PUNCH ENGAGEMENT ADJUSTMENT
If the punch engagement should need adjustment, loosen the set
3