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-13-
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 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.
RUNNING NUTS AND BOLTS
Variable speed control must be used with
caution for driving nuts and bolts with
socket set attach ments. The technique is to
start slowly, increasing speed as the nut or
bolt runs down. Set the nut or bolt snugly
by slowing the drill to a stop. If this
procedure is not followed, the tool will
have a tendency to torque or twist in your
hands when the nut or bolt seats.
2610056734 02-21 PS11_BM 2610022006 04-12.qxp 2/15/21 10:39 AM Page 13
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