The electric drill is the most widely owned power tool. A common fault is a parted power cord, caused by carrying the tool by its cord instead of its handle or by improperly disconnecting the cord from an electrical outlet. If the drill will not run, lock the trigger switch in the on position and wiggle the cord back and forth, both where it enters the drill and at the plug . If the drill then runs in intermittent spurts, o­ne of the power cord wires has broken. If it is broken near the plug, you can cut the cord beyond the damaged area, strip back the insulation, and attach a new plug. If it is broken where the cord enters the drill, you may have to replace the entire cord; many cords have a molded-on rubber cushin where the cord meets the tool, and cannot be shortened easily.

Other common problems are a rotor, a commutator, or brushes that are burned as a result of overloading the tool. Any power tool should be allowed to work at its own pace. Do not bear down o­n the tool with excessive pressure. Do not use dull bits or blades. And do not use a bigger bit or blade than the tool was designed to accept. Sharp drill bits work better than dull o­nes. And the drill user is therefore less likely to bear down o­n the tool and overload the motor. A sharp twist bit cuts curlicue shavings from wood and metal; a dull bit scrapes away small chips. An extra dull bit produces a lot of heat and may cause wood to smolder. Dull twist bits should be sharpened at various angles to make it more suitable for drilling various materials. Use special masonry bits o­n brick or cement.

Troubleshooting

Problem: Motor does not run

Check for current at outlet with a lamp you know is working. If there is no power, check fuses or circuit breakers and house wiring.

Check power cord for fraying or bent prongs

Test cord with a volt-ohm meter.

With tool unplugged, turn fan or motor through several rotations by hand. If tool then runs, o­ne rotor or commutator segment is faulty. You may use tool temporarily, but should repair motor as soon as possible.

Inspect brushes for wear or sticky action. Replace worn or pitted brushes; free sticking brushes.

Spray commutator with electrical contact cleaner.

Test switch with volt-ohm meter; replace if necessary.

Problem: Motor hums but does not run

With tool unplugged, turn fan or motor through several rotations by hand. If it cannot be turned, disassemble tool and motor, looking for jammed gears, rotor striking field, a bent fan, or frozen bearings. If motor can be turned, then runs when plugged in, a rotor or commutator segment is faulty.

Remove tool from work. If it then operates, tool was overloaded. Allow tool to reach operating speed before applying it to work. Work more slowly and do not apply as much pressure. Make sure bit or blade is not too big for tool.

Problem: Tool is noisy, vibrates

Tighten bit or blade if loose. If tight, remove and reposition bit or blade. Replace a warped or broken bit or blade. Open housing and tighten all screws, nuts, bolts. Replace worn rubber mounts. Be sure fan is o­n tightly. Clean debris from rotor and field. Replace rotor if commutator bars are loose. Check bearings for wear.

Problem: Tool dropped in water

Turn off power at fuse box, shake water out of tool, allow to dry in a warm, dry place such as a furnace room. Disassemble and clean tool if it was submerged in muddy water. If it was soaked in salt water, flush with tap water