Bosch HD21-2 Consignes De Fonctionnement/Sécurité page 10

2610048706.qxp_HD21-2 10/5/17 10:45 AM Page 10
You will extend the life of your bits and do
neater work if you always put the bit in
contact with the work before pulling the
trigger. During the oper a tion, hold the tool
firmly and exert light, steady pressure. Too
much pressure at low speed will stall the tool.
Too little pressure will keep the bit from
cutting and cause excess friction by sliding
over the surface. This can be damaging to
both tool and bit.
DRILLING WITH VARIABLE SPEED
The trigger controlled variable speed feature
will eliminate the need for center punches in
hard materials. The variable speed trigger
allows you to slowly increase RPM. By using
a slow starting speed, you are able to keep
the bit from "wander ing". You can increase
the speed as the bit "bites" into the work by
squeezing the trigger.
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 ma terials.
CARBIDE TIPPED BITS: Used for drilling
stone, con crete, plaster, cement and other
unusually hard nonmetals. Use continuous
heavy feed pres sure when employing carbide
tip bits.
DRILLING WOOD
Be certain workpiece is clamped or anchored
firm ly. Always apply pressure in a straight line
For selection of dust collection systems and
operating instructions, see the Operating /
Safety Instructions for 'Dust Extraction
*Always follow manufacturer instructions*
Operating Tips
Dust Extraction
*AAA Rent-All 225-291-1356*
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
pres sure 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.
Lubri cate the tip of the bit occasionally with
cutting oil except when drilling soft metals such
as alu minum, cop per 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. Main tain 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
Use carbide-tipped masonry bit for cinder block,
mortar, common brick, soft stone and other
materials. The amount of pressure to be used
is dependent upon the type of material being
drilled. Soft materials require less pressure
while the hard materials need more pressure to
prevent the drill bit from spinning.
Attachments for Hammers and Hammer Drills'
included with your tool or with the dust
extraction attachment.
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