Dewalt DCH273B Instruction Manual - Page 16

English 4. Hold tool firmly with both hands to control the twisting action of the drill. If model is not equipped with side handle, grip drill with one hand on the handle and one hand on the battery pack. WARNING: Drill may stall if overloaded causing a sudden twist. Always expect the stall. Grip the drill firmly to control the twisting action and avoid injury. 5. IF DRILL STALLS, it is usually because it is being overloaded or improperly used. RELEASE TRIGGER IMMEDIATELY, remove drill bit from work, and determine cause of stalling. DO NOT DEPRESS TRIGGER ON AND OFF IN AN ATTEMPT TO START A STALLED DRILL - THIS CAN DAMAGE THE DRILL. 6. To minimize stalling or breaking through the material, reduce pressure on drill and ease the bit through the last fractional part of the hole. 7. Keep the motor running when pulling the bit back out of a drilled hole. This will help prevent jamming. 8. With variable speed drills there is no need to center punch the point to be drilled. Use a slow speed to start the hole and accelerate by squeezing the trigger harder when the hole is deep enough to drill without the bit skipping out. DRILLING IN METAL An SDS Plus® to round shank adaptor chuck is required. Ensure that tool is in drill-only mode. Start drilling with slow speed and increase to full power while applying firm pressure on the tool. A smooth even flow of metal chips indicates the proper drilling rate. Use a cutting lubricant when drilling metals. The exceptions are cast iron and brass which should be drilled dry. NOTE: Large (5/16" to 1/2" [7.9 mm to 12.7 mm]) holes in steel can be made easier if a pilot hole (5/32" to 3/16" [4 mm to 4.8 mm]) is drilled first. DRILLING IN WOOD An SDS Plus® to round shank adaptor chuck is required. Ensure that tool is in drill-only mode. Start drilling with slow speed and increase to full power while applying firm pressure on the tool. Holes in wood can be made with the same twist drills used for metal. These bits may overheat unless pulled out frequently to clear chips from the flutes. For larger holes, use spade bits, power auger bits, or hole saws. Work that is apt to splinter should be backed up with a block of wood. DRILLING IN MASONRY When drilling in masonry, use carbide-tipped bits rated for percussion drilling and be certain that the bits are sharp. Use a constant and firm force on the tool to drill most effectively. A smooth, even flow of dust indicates the proper drilling rate. HAMMERDRILL OPERATION (FIG. 4) 1. Turn the mode selector (D) to the rotary hammer symbol (K). 2. When drilling, use just enough force on the hammer to keep it from bouncing excessively or "rising" off the bit. Too much force will cause slower drilling speeds, overheating, and a lower drilling rate. 3. Drill straight, keeping the bit at a right angle to the work. Do not exert side pressure on the bit when drilling as this will cause clogging of the bit flutes and a slower drilling speed. 4. When drilling deep holes, if the hammer speed starts to drop off, pull the bit partially out of the hole with the tool still running to help clear debris from the hole. 5. For masonry, use carbide-tipped bits or masonry bits. A smooth even flow of dust indicates the proper drilling rate. Chipping and Chiselling (Fig. 4) 1. Set the mode selector switch (D) to the chipping symbol (L). 2. Insert the appropriate chisel and rotate it by hand to lock it into one of 51 positions. 14