Hammer Drills and SDS Drills are both ideal for drilling effectively into concrete, masonry or stone and, with the hammer action turned off, into metal and wood. In both styles of machines the hammer action (when on Hammer Mode) helps to break up the material so that it can be removed by the drill bit's flutes. In many cases both of these styles are available in both 240 Volt (mains power) or 110 Volt (Site usage). There are also a growing selection of Cordless SDS Plus Drills now available.

The Difference

Hammer Drills, also known as Impact or Percussion drills, have a specially designed clutch that allows it to not only spin the drill bit, but also to punch it in and out. The actual distance the bit travels in and out and the force of its blow are both very small but the hammering action is very rapid, thousands of BPM - Blows per Minute or IPM - Impacts per minute. These machines use standard smooth shank drill bits and as such they have either a Keyless or Keyed Chuck. Toolbank stock a detailed range of Hammers Drills with power varying from 500-690 Watts and 700-1050 Watts, the higher the wattage the more powerful the machine. Cordless versions of a Hammer Drill are known as Combi Drills and are available in a wide range of Voltages.

SDS Rotary Hammers are similar to Hammer Drills in that they also pound the drill bit in and out while it's spinning. They use a piston mechanism instead of a special clutch enabling them to deliver a much more powerful hammer blow than traditional Hammer Drills - they are able to drill larger holes much faster.

There are three main types of SDS Hammer Drills :

Compact Hammers - These are the most commonly used of the SDS range and use the SDS Plus bits

Midsize Hammers - Suitable for heavier-duty applications and do not operate in a rotary only mode. These use the SDS-Max bits.

Demolition Hammers - For demolition work and heavy-duty use and do not operate in rotary only mode.

SDS Drills also operate in either 2 or 3 modes; machines with 2 modes offer Rotary Action (Impact Stop) or Hammer Action, whilst 3 mode machines offer both these plus a Rotation Stop function which switches off the Rotary Action and leaves just the Hammer Action - allowing the drill to be used as a breaker or demolition hammer with a suitable chisel bit. SDS Max machines are used in heavier-duty and larger applications and operate in 1 of 2 Modes only - Rotary Hammer or Rotation Stop.

SDS Rotary Hammers have such force that the usual masonry bits are not suitable. Their smooth shanks would be pounded loose from the tool's chuck in a few seconds. These machines require special SDS bits which can lock into the rotary hammer and continue to spin while smashing away. Also due to the nature of the work they do it means that SDS drills require a clutch which cuts in when the drill bit jams - thus stopping the violent wrenching motion that a drill without a clutch would cause when stopped suddenly from full speed.

There are two standard SDS bit sizes :

SDS-Plus: Which has a 10mm shank with two open grooves held by the driving wedges and two closed grooves held by locking balls, this is the most common size and takes a hammer up to 4kg.

SDS-Max: These bits have an 18mm shank with three open grooves and locking segments rather than balls, these are designed for use in SDS hammers over 5kg.