SDS (Special Direct System) drills have been on the market since 1975. Some people may see them as an advanced version of a regular hammer drill, because they provide enhanced strength in their hammer blows. Where the regular hammer drill requires a great deal of movement in the clamp in order to exert the hammer force, an SDS drill enables the drill bit to move while inside the clamp, which results a more precise and accurate hammer force. When drilling through substances that require a great deal of force to get through, such as bricks or concrete, this extra precision can be very valuable. Anyone who needs to drill through these substances on a regular basis will appreciate this enhanced functionality. It is estimated that SDS drills can drill through these substances ninety percent faster than regular hammer drills can.
Settings on an SDS drill are often drill only, hammer (or chisel) only, which is useful for brick and tile removal or cutting in electric sockets or outlets, and drill and hammer, which, despite improved functionality, operates much quieter than regular hammer drills. Some brands, however, only include the drill and drill and hammer settings.
SDS drills have several important features. This includes safety mechanisms that turn the power off in the event the drill bit becomes embedded in the substance being worked on. This prevents the person using the drill from losing control of the drill, potentially causing it to harm the person using it or anyone who may be in the vicinity, or causing it to destroy or break the item being drilled.
The DeWalt D25313K SDS Plus Drill is one of the better SDS drills on the market. For its power, it is relatively lightweight, weighing in at only 2 kilograms. It offers three settings, drill, drill and hammer, and chisel, and various speeds to which it can be adjusted. It also comes with a safety clutch and a grip coated in rubber for firm handling.
The Hitachi DH24DVA SDS Plus Drill also features three settings, including drill, drill and hammer and chisel, and has the capability to drill at high speeds. It has a setting for saving power as well, and boasts a safety clutch, and electric brake and a lock-off switch.