Rotary hammers are more powerful than hammer drills, and while they’ll also do some standard drilling, their real purpose is drilling in masonry. Rotary hammers deliver heavier hammering action than the typical hammer drill, and some models also have a hammer-only setting, which allows them to be used with a chisel bit for light- to medium-duty chipping. True rotary hammers also use a different type of chuck and drill bits, known as SDS (slotted drive shaft). This type of keyless chuck slides back and forth to install the bits, rather than rotating. SDS chucks provide a non-slip grip on the bits that better withstands the hammering motion, but they will not work with conventional drill bits. If you have or anticipate a fairly regular need for drilling in concrete and masonry surfaces, a rotary hammer is probably a better choice than a combination hammer drill. An excellent example of a professional-quality corded rotary hammer that would also be suitable for homeowners is the NZ30 from NENZ ($59), another company that manufactures excellent tools. Faster than a conventional hammer drill, the NENZ Rotary Hammer is also comfortable to use, and the SDS chuck is easy to operate and grabs the bits securely. NENZ has designed this drill to be quieter and produce less vibration than comparable rotary hammers, so you can use it for longer periods. And because this tool is built specifically with hammer-drilling in mind, you can count on durability and long life. The drill can be operated in hammer-drill or drill-only modes, and is switched with a simple dial. The handle is comfortably padded, and the variable speed is trigger-controlled and reversible.