How to choose an SDS-Max combination hammer: weight class

The SDS-Max combination hammer does two jobs: it drills concrete with rotation and percussion, and it chisels with the rotation switched off. Choose the weight class according to the hole diameter: 5 kg for holes up to about 40 mm, 7 kg around 45 mm, 8-10 kg and above for larger holes, up to 52 mm in the collection. If you only need to demolish, a demolition hammer is more suitable; if you need to make deep, large holes, the combination hammer is the right machine.

The types

• Corded combination hammer: mains powered, with power from about 1,100 to 1,700 W. It is the model most used for continuous drilling.
• Cordless combination hammer: 18 V models (such as the Milwaukee M18 FUEL) and 54 V models (DeWalt FlexVolt). An example is the M18 FUEL 5 kg class, 40 mm or the DeWalt 54 V 48 mm.
• Combination hammers by weight class: Milwaukee classifies them by class: 5 kg, 7 kg, 8 kg and 10 kg.
• SDS-Max hammer drill: such as the DeWalt 54 V 48 mm model, with the same drilling function.

How to choose by job

The features to check

• Weight (from about 5 to 12 kg): this is the machine's class. The heavier it is, the greater its drilling capacity, but the harder it is to move around.
• Drilling diameter (40, 45, 48, 52 mm): this is the drilling capacity given on the product sheet. Take the machine that covers your largest hole with a little margin.
• Power (from 600 to 1,700 W): look at the power together with the weight and the diameter; on its own it is not enough to compare two machines.
• No-load speed: varies a lot between models, from about 125 to over 500 rpm in combination hammers.
• Power source and voltage: corded, or cordless at 18 or 54 V.
• Dimensions: length from about 450 to 630 mm: they matter in tight spaces.
• Side handle and depth rod: they are used to hold the machine with both hands and to stop the hole at the required depth. Check that they are present and adjustable.
• Battery included or not: on several cordless models you buy only the machine body. If you are starting from scratch, check that batteries and charger are in the kit.

Common mistakes

• Taking a class that is too small for large holes. The machine struggles and the job takes twice as long.
• Pushing too hard. The weight does the work by itself: if you press down, you strain the machine and the bit.
• Forgetting to check for cables and pipes in the wall. Before drilling, check that no services run through that spot.
• Not greasing bits and chisels. The SDS-Max shank must be kept clean and greased.
• Confusing a combination hammer with a demolition hammer. The first drills and chisels, the second only chisels.
• Underestimating the batteries. A cordless combination hammer uses large batteries: work out how many you need for a full shift.

Frequently asked questions

What is the difference between a combination hammer and a demolition hammer?

The combination hammer drills with rotation and percussion, and chisels with the rotation switched off. The demolition hammer has percussion only.

What weight class do I need?

It depends on the hole diameter: 5 kg for about 40 mm, 7 kg for about 45 mm, 8-10 kg for the larger diameters.

Corded or cordless: which is better?

With a cordless one you work without a cable, but look at the capacity and the number of batteries. With a corded one you have continuous power.

Can it be used for chiselling?

Yes: you switch off the rotation and the machine works with percussion only, using an SDS-Max chisel.

What protection is needed?

Goggles, ear protection, a dust mask and gloves. In concrete the dust is fine and abundant, so the dust mask matters as much as the ear defenders.

You will find the models in the Combination hammers collection: to choose the right weight class, request a quote or ask the AMES technicians for advice.