Skil HD527801 Guide D'utilisation page 18

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 fairly 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.
Wood Drilling
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
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of wood behind the workpiece to prevent
ragged or splintered edges on the back side
of the hole (Fig. 11).
NOTICE: Bits may overheat unless 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
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prolong the life of the bit and increase the drilling action.
Begin drilling at a very low speed to prevent the bit from slipping off the starting point.
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Maintain a speed and a pressure that allow cutting without overheating the bit. Applying too
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much pressure will:
Overheat the Drill.
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Wear the bearings.
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Bend or burn bits.
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Produce off-center or irregularly shaped holes.
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Fig. 11