Bosch DDH181X Consignes De Fonctionnement/Sécurité page 13

BM 2610032842 04-14_DDH181X HDH181X 4/9/14 7:10 AM Page 13
Second, unclamp the pieces and drill the
second hole the same diameter as the screw
shank in the first or top piece of wood.
Third, if flat head screw is used, countersink
the hole to make the screw flush with the
surface. Then, simply apply even pressure
when driving the screw. The screw shank
clearance hole in the first piece allows the
screw head to pull the pieces tightly together.
The adjustable screw drill accessory will do
all of these operations quickly and easily.
Screw drills are available for screw sizes No.
6, 8, 10 and 12.
DRILL BITS
Always inspect drill bits for excessive wear. Use
only bits that are sharp and in good condition.
TWIST BITS: Available with straight and
reduced shanks for wood and light duty metal
drilling. High speed bits cut faster and last
longer on hard materials.
CARBIDE TIPPED BITS: Used for drilling
stone, concrete, plaster, cement and other
unusually hard nonmetals. Use continuous
heavy feed pressure when employing carbide
tip bits.
DRILLING WOOD
Be certain workpiece is clamped or anchored
firmly. Always apply pressure in a straight line
with the drill bit. Maintain enough pressure to
keep the drill "biting".
When drilling holes in wood, twist bits can be
used. Twist bits may overheat unless pulled out
frequently to clear chips from flutes.
Use a "back-up" block of wood for work that is
likely to splinter, such as thin materials.
You will drill a cleaner hole if you ease up on
the pressure just before the bit breaks through
the wood. Then complete the hole from the
back side.
DRILLING METAL
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.
Here are a couple of tips for drilling in metal.
Lubricate the tip of the bit occasionally with
cutting oil except when drilling soft metals such
as aluminum, copper or cast iron. If the hole to
be drilled is fairly large, drill a smaller hole first,
then enlarge to the required size, it's often
faster in the long run. Maintain enough
pressure to assure that the bit does not just
spin in the hole. This will dull the bit and greatly
shorten its life.
DRILLING MASONRy
Soft materials such as brick are relatively easy
to drill. Concrete however, will require much
more pressure to keep the bit from spinning. Be
sure to use carbide tip bits for all masonry work.
Before using an accessory,
W RNING
be certain that its maximum
safe operating speed is not exceeded by the
nameplate speed of the tool. Do not exceed
the recommended wheel diameter.
SANDING AND POLISHING
Fine sanding and polishing require "touch".
Select the most efficient speed.
When using polishing bonnets, always be sure
the excess string that secures the bonnet is
tucked well within the bonnet during operation.
WIRE BRUSHES
Work with brushes requires high speeds.
BRUSHING PRESSURE
1. Remember, the tips of a wire brush do the
work. Operate the brush with the lightest
pressure so only the tips of the wire come in
contact with the work.
2. If heavier pressures are used, the wires
will be overstressed, resulting in a wiping
action; and if this is continued, the life of the
brush will be shortened due to wire fatigue.
3. Apply the brush to the work in such a way
that as much of the brush face as possible is
in full contact with the work. Applying the
side or edge of the brush to the work will
result in wire breakage and shortened brush
life.
CORRECT: Wire tips doing the work.
INCORRECT: Excessive pressure can cause wire breakage.
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