BOSCH GBH18V-45C 18v Brushless SDS MAX Hammer Drill BODY + Case

Cordless SDS Max Hammers are tools which pack a lot of punch. They’re so strong that many are designed for demolition. Because their primary role is as a hammer drill, the impact rate – measured in either impacts per minute (ipm) or blows per minute (bpm) is definitely an important characteristic to consider. You should also check the maximum drilling capacity, which determines how far the tool will go into the material you’re working with.

One significant difference between these kinds of tools is the size of the shank. SDS Plus bits typically have a 10mm shank, while SDS Max is 18mm. This means that an SDS Max tool can use SDS Plus drill bits with an adaptor, but SDS Max bits aren’t ‘backwards’ compatible. The other main difference is that an SDS Max drill has even more power than an SDS Plus tool and is designed for working on tougher jobs than you might use the SDS Plus machine for.

Brushed motors use carbon brushes to transfer power from the fixed part of the motor to the rotor. This creates a reliable and relatively inexpensive motor, but brushed motors require regular maintenance, in order to either clean the brushes or replace them as they wear out. A brushless motor, by contrast, uses a magnet mounted on the rotor to generate the power and electrical switching to perform the function carried out by the brushes. The additional complexity of the motor’s working means that brushless motors are usually more expensive than brushed.

However, eliminating the brushes also eliminates internal friction and maintenance, meaning that brushless motors offer both increased power and a longer working life. Brushless motors also generate less heat and noise and so, on balance, are considered superior to brushed motors.

That depends entirely on what your SDS Max Hammer needs to do. One useful rule of thumb is to remember that the higher the voltage of the tool, the more it should be able to do. As an example, a 12v machine will usually have a drilling capacity in concrete of less than 15mm; the new 54v tools from DeWalt can drill to 100mm with a Core bit. We also have 18v, 36v and 40v options, from leading brands including Hikoki and Makita.