1. Electric drill BADI 1 John Errington

2. engineering considerations for design  Safe use of electricity – possible damp and dirty conditions  Suitability of materials for each part of the drill.  Accommodation of moving parts.  Transfer of rotating motion from motor to chuck

3. Rotary drill: De Walt 241

4. Specification: Dewalt Dw241L 110V Rotary Drill 13Mm 701W  2 Speed Rotary Drill  Extremely Long brush life.  Power to weight ratio best for continuous use.  High torque reversible motor.  Power Input 701 Watt  Chuck Capacity 13 mm Keyless  Max torque 35/15 Nm  No load speed 0 -1100 / 0-2700 RPM  Max capacity –Wood 35 mm –Steel 13 mm  Voltage 110V or 230V models available  Chuck 13mm.  Standard: Side Handle & Depth Stop.

5. Schematic of gearbox and chuck

6. Electrical components and housing

7. Rotary and fixed hammer drills (SDS +)

9. Dewalt D25002K 240V Sds Plus Rotary Hammer  Ideal for drilling anchor and fixing holes into concrete and masonry from 4 to 22mm in diameter  Impact-stop for drilling in wood, steel, ceramic and screwdriving applications  Full wave electronic variable speed for total control in any application  Safety clutch eliminates sudden high-torque reaction should the bit jam  Ergonomic rubber coated pistol grip handle design for improved comfort in use  High drilling rate due to revolutionary motor design  Includes :multi-position side handle, depth stop, Heavy duty carrying case  Power Input: 600 Watts  Power Output: 380 Watts  No Load Speed: 0-1100 rpm  Blows per Minute: 0-4000 bpm  Impact Energy: 0-2.4 J  Tool Holder: SDS-Plus  Max. Drilling Capacity [Wood]: 30 mm  Max. Drilling Capacity [Metal]: 13 mm  Max. Drilling Capacity [Concrete]: 22 mm  Max. Drilling Capacity [Core bit]: 65 mm  Weight: 2.3 kg  Length mm: 360 mm  Height: 205 mm

10. Mechanical components of sds+ impact drill

11. Electrical parts and casing of sds+ impact drill