FASTENING2. Drill same dia-with the drill bit. Maintain enough pressure to
meter askeep the drill Obiting�.
WITH SCREWS
screw shank.
When drilling holes in wood, twist bits can be
3. Countersink
1. Drill 2/3 diameter andsame diameterused. Twist bits may overheat unless pulled out
2/3 of screw length foras screw head.frequently to clear chips from flutes.
soft materials, full
length for hardAdjustableUse a Oback-up� block of wood for work that is
Screw likely to splinter, such as thin materials.materials.
ScrewDrill
You will drill a cleaner hole if you ease up on
the pressure just before the bit breaks through
Apply a slight
even pressurethe wood. Then complete the hole from the
when drivingback side.
screws.
DRILLING METAL
There are two rules for drilling hard materials.
First, the harder the material, the greater the
FIG. 5
pressure you need to apply to the tool. Second,
the harder the material, the slower the speed.
Second, unclamp the pieces and drill the
Here are a couple of tips for drilling in metal.
second hole the same diameter as the screw
Lubricate the tip of the bit occasionally with
shank in the first or top piece of wood.
cutting oil except when drilling soft metals such
Third, if flat head screw is used, countersinkas aluminum, copper or cast iron. If the hole to
the hole to make the screw flush with thebe drilled is fairly large, drill a smaller hole first,
surface. Then, simply apply even pressurethen enlarge to the required size, itOs often
when driving the screw. The screw shankfaster in the long run. Maintain enough
clearance hole in the first piece allows thepressure to assure that the bit does not just
screw head to pull the pieces tightly together.spin in the hole. This will dull the bit and greatly
shorten its life.
The adjustable screw drill accessory will do
all of these operations quickly and easily.DRILLING MASONRY
Screw drills are available for screw sizes No.Soft materials such as brick are relatively easy
6, 8, 10 and 12.to drill. Concrete however, will require much
DRILL BITSmore pressure to keep the bit from spinning. Be
Always inspect drill bits for excessive wear.sure to use carbide tip bits for all masonry work.
Use only bits that are sharp and in goodBefore using an accessory,
condition.!be certain that its maximumWARNING
TWIST BITS: Available with straight andsafe operating speed is not exceeded by the
reduced shanks for wood and light duty metalnameplate speed of the tool. Do not exceed
drilling. High speed bits cut faster and lastthe recommended wheel diameter.
longer on hard materials.
SANDING AND POLISHING
CARBIDE TIPPED BITS: Used for drillingFine sanding and polishing require Otouch�.
stone, concrete, plaster, cement and otherSelect the most efficient speed.
unusually hard nonmetals. Use continuous
When using polishing bonnets, always be sure
heavy feed pressure when employing carbidethe excess string that secures the bonnet is
tip bits.
tucked well within the bonnet during operation.
DRILLING WOOD
Be certain workpiece is clamped or anchored
firmly. Always apply pressure in a straight line
-11- |
ACEC
BOSCH
