Hammer Drill                                 Rotary Hammer

I grouped the Hammer Drill with the Rotary Drill because even though they are different, they are pretty much the same.  A Hammer Drill can rotate and move back and forth while it drills which allows it to bore into concrete without burning the bit.  A Rotary Hammer Drill works on the same principle, but is much more powerful than a Hammer Drill.  A Rotary Hammer usually has a chisel feature, which allows the user to do light chiseling.  A Rotary Hammer usually has its own special bit designed for the chuck of the Rotary Hammer Drill which prevents slipping.

Features

• Variable Speed Selection – Allows the user to adjust speeds on the drill.  High speeds are used for small holes while slow speeds are used for large holes.
• Reverse – Allows the user to back a bit out of the hole since they tend to get stuck easily.
• Depth Rod – A devise mounted on the side of the drill that lets the user know when they have reached the desired depth.
• Side Handle – Allows the user to use an additional hand to hold the tool while drilling which gives better control.  Most can be removed in case you are in a tight spot.

Drive Systems

• SDS (Slotted Drive System) – At the end of these bits there are slots that match to the inside of the chuck on the drill.  This holds the bit tight and will not slip, such as a normal chuck can do under such pressures.  It also enhances the hammering action.  SDS bits are harder to find and tend to be more expensive than regular drill bits.
• SDS Max – These are the same as the SDS bits but have a larger shank.  SDS Max bits are used for larger applications.  Again these bits are a little more expensive, but worth it in the long run.