What SDS Drill Bits Are
SDS bits are made for rotary hammers and some hammer drills that have an SDS chuck. Instead of a round shank gripped by jaws, an SDS bit has grooves in the shank. The groove pattern lets the bit slide back and forth in the chuck, which allows the tool’s hammering action to reach the bit with less loss than a conventional chuck. The bit is also locked in by balls or pins in the chuck, so it can be changed without a key.
The name is usually explained as coming from German words, often given as “Steck-Dreh-Sitz” (insert, twist, sit), and sometimes reported in English as “Slotted Drive System”. Sources differ, so treat the origin as a piece of trivia rather than something that affects use.
SDS bits are mainly used in concrete, brick, block and stone. Their cutting tip is typically carbide.
SDS-Plus and SDS-Max
The two shanks you will see most are SDS-Plus and SDS-Max.
| SDS-Plus | SDS-Max | |
|---|---|---|
| Shank diameter | About 10 mm | About 18 mm |
| Typical tools | Lighter rotary hammers | Larger, heavier rotary hammers |
| Typical use | Smaller to medium holes, anchors, general building work | Larger holes, heavy demolition, long drilling |
SDS-Max is the larger of the two, and the two systems are not interchangeable without an adapter or tool designed for both. Check the tool’s manual for what it accepts and for the bit sizes it supports. Some older or regional systems, such as plain “SDS” and “SDS-Top”, also exist and are less common.
For an overview of other shank styles, see drill shank and chuck types.
Types of SDS Bits by Function
SDS Masonry Drill Bits
These are the most common. A carbide tip sits on a steel body with deep flutes that remove dust. They come in many diameters and lengths and are used for anchor holes, fixings, and holes through concrete and brick.
SDS Core Bits
Core bits cut a ring and leave a plug, which suits large holes for pipes or vents. Some are designed for SDS-Max machines. Manufacturers vary in whether a given core bit is meant for hammer action, so check the product details.
SDS Chisels
Chisels are not drill bits, but they use the same shank. Pointed chisels break material, flat chisels trim and scrape, and spade or wide chisels clear larger areas such as tile or plaster. They need a rotary hammer with a chisel-only mode, usually described as hammer-only.
Other SDS Accessories
Some makers offer SDS adapters for conventional chucks, rebar-cutting bits, and dust extraction attachments. Dust control is important when drilling concrete; follow the safety guidance for the tool and the material, and use suitable eye and respiratory protection.
Choosing the Right SDS Bit
- Match the shank to the tool. SDS-Plus bits for SDS-Plus tools, SDS-Max for SDS-Max.
- Match the size and length to the job. Choose a bit long enough for the depth, with some spare length for clearing dust.
- Consider the material. Concrete with reinforcing steel can damage carbide tips; some bits are designed to cope with rebar better than others.
- Use the right mode. Rotation with hammering for drilling, hammer-only for chiselling.
FAQ
What is an SDS drill used for?
It is used mostly for drilling and chiselling in masonry and concrete, where its stronger hammering action works faster than an ordinary drill.
Which is bigger, SDS-Max or SDS-Plus?
SDS-Max. Its shank is larger and it is meant for heavier tools and bigger holes.
Can I use an SDS bit in a regular drill?
Not directly, since the grooved shank does not fit a standard jaw chuck. Adapters exist, but they remove the benefit of the SDS design.
How is an SDS drill different from a hammer drill?
A conventional hammer drill creates its impact through a clutch-like mechanism, while an SDS rotary hammer uses a piston that delivers a stronger impact. For lighter masonry jobs, other masonry bits in a hammer drill may be enough; see the overview of drill bit types.