Hammer Drill

• The hammer drill provides a short, rapid hammering force to pulverize hard materials and help you drive a bit into concrete.
  
  

Uses For Hammer Drills

• The hammer drill is for drilling into masonry, often needed when fastening something to a concrete wall, beam or floor.
  
  

Impact Driver

• Impact drivers are like electric screw drivers that provide hammering motion and increased torque. They reduce the amount of force you need to drive screws or loosen bolts, saving your wrists and arms from fatigue.
  
  

Uses For Impact Drivers

• Carpenters use impact drivers for fastening screws into wood or drywall and mechanics use them for loosening bolts.
  
  

Differences

• Hammer drills are heavier duty and have either a chuck that will take a regular drill bit or a special bit for drilling into specific materials.
  Impact drivers are lighter duty and have no chuck. They take only 1/4-inch hexagonal bits. They can rotate either clockwise or counterclockwise for tightening and loosening.