Rotary hammers (also called combi-drill or combi-hammers) are amazing power tools. Rotary hammers usually also have a feature for chiseling mode. Don't get confused between a rotary hammer and a hammer drill as they are two separate power tools. Both are used for concrete work and both hammer in and out while spinning. However, the internal mechanism is much different and much more robust with a rotary hammer. A rotary hammer uses a piston mechanism instead of a clutch.
The piston mechanism is what allows these tools to drill bigger holes and drill them faster. They can produce much more power and brute force than a hammer drill.
Since these tools produce so much force, they need to have special bits. There are three types of bits for rotary tools.
Shank Bit Types
- 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+ are designed for smaller shank sizes and some chiseling.
- SDS Max – These are the big brother bits to the SDS+. They were designed to replace the spline shank. SDS Max bits are used for larger applications.
- Spline Shank – These are identical to the SDS Max except for the chucks. The tool and bit selection will be small since these is an older type of shank.
- 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 device 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.