Bosch 1199VSR Operating Instructions - Page 9

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. ! WARNING Before using an accessory, 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 You will find the "Lock-ON" button feature a convenience for the continuous operation required for rough sanding. Fine sanding and polishing require "touch". Select the most efficient speed. When using polishing bonnets, alway 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. Use of the "Lock-ON" button feature will provide a much easier operation. 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. 15° INCORRECT: Excessive pressure can cause wire breakage. RUNNING NUTS AND BOLTS Variable speed control must be used with caution for driving nuts and bolts with socket set attachments. 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. -9-