The rational choice of a hammer drill must take into account 5 criteria.
Tool weight and power:
- lightweight - up to 3 kg and up to 700 W;
- medium - up to 5 kg and up to 900 W;
- heavy - from 5 kg and above 1000 W.
Impact force is the key criterion:
- lungs: 2.6-4.5 J;
- medium: 4.6-7.9 J;
- heavy: 8 J and more.
The greater the impact force, the easier it is to drill holes of huge diameter. But light punchers can do it too.
Operating modes (better more):
- shockless (drill mode) - requires a special cartridge;
- hammer drilling - for drilling holes;
- chiselling - for chipping, creating recesses, dismantling.
- SDS-Plus - the most common, used in light and medium, for drills 4-32 mm in diameter;
- SDS-Max - used in heavy drills, 12-50 mm in diameter;
- SDS-Ouick - developed by Bosch, practiced in single tools.
- coaxial (with horizontal layout) - the engine and the percussion mechanism are located on the same axis;
- with vertical engine layout.
The layout does not affect the capabilities of the rock drill in any way. Do not pay attention to it.
See the Bosch overview, in particular the GBH 2-20 D and GBH 2-24 DFR models
Which hammer drill is better: the pros advise to be simple
Professionals say: the only reason for buying a professional rotary hammer for home is the extra money down the drain and the desire to get a branded item. It is distinguished from everyday life only by an increased resource. But if you are not going to work 3-5 hours daily, then the resource of the household tool will be enough for years.
At home, many pros use products from non-promoted Chinese brands. It is important that the brand has a service center. This ensures that the manufacturer cares about quality.
Punch choice: additional nuances
- Lamellar (flag): comfortable, but afraid of dust.
- Push-button: handy, afraid of dust.
- Brush: the most reliable. Significantly extends the service life of the rotary hammer's electric brushes, does not lose the number of revolutions and power when rotated to the left.
Comfort and safety:
- Anti-vibration system - reduces discomfort from prolonged work.
- Safety clutch - if the drill is jammed, the rock drill shuts down.
See Makita Review