Flex FX1171T Manuel De L'utilisateur page 18

d. Depress the variable-speed trigger switch to
start the drill.
e. Move the drill bit into the workpiece, applying
only enough pressure to keep the bit "biting".
Do not force the drill or apply side pressure to
elongate a hole. Let the tool do the work.
f. When drilling hard, smooth surfaces, use a
center punch to mark the desired location of
the hole. This will prevent the drill bit from
slipping off-center as the hole is started.
g. When drilling metals, use light oil on the drill
bit to keep it from overheating. The oil will
prolong the life of the bit and increase the
drilling efficiency.
WOOD DRILLING (FIG. 18)
For maximum performance, use high-speed
steel or brad-point bits for wood drilling.
Begin drilling at a very low speed to prevent
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the bit from slipping off the starting point.
Increase speed as the drill bit bites into the
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material.
When drilling "through" holes, secure a block
•
of wood behind the workpiece to prevent
ragged or splintered edges on the back side of
the workpiece
NOTICE: Bits may overheat unless reversed
and pulled out frequently to clear chips from
flutes.
METAL DRILLING
For maximum performance, use high-speed
steel bits for metal or steel drilling.
When drilling metals, use light oil on the drill
•
bit to keep it from overheating. The oil will
prolong the life of the bit and increase the
drilling efficiency.
Begin drilling at a very low speed to prevent
•
the bit from slipping off the starting point.
h. If the bit jams in the workpiece or if the drill
stalls, stop the tool immediately. Remove the
bit from the workpiece and determine the
reason for jamming.
There are two rules for drilling hard materials.
First, the harder the material, the greater the
pressure you need to apply to the tool. Second,
the harder the material, the slower the speed
should be. If the hole to be drilled is large, drill
a smaller hole first, and then enlarge to the
required size with a larger bit – it's often faster
in the long run.
Fig. 18
Maintain a speed and a pressure that allow
•
cutting without overheating the bit. Applying
too much pressure will:
Overheat the Drill.
–
Wear the bearings.
–
Bend or burn bits.
–
Produce off-center or irregularly shaped holes.
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