" None of those drills is suitable for driving ground rods. They are all
regular electric drills, with a conventional 3-jaw chuck and a lightweight
hammer action that depends on the chuck going round.

For driving ground rods, you need a different kind of 'hammer' drill that
has a separate high-impact hammer action, that can be used *without* the
chuck going round.

The SDS+ system is the Bosch company's patented method to build hand-held
electric drills with a *serious* high-impact hammer action. The system has
been widely licensed to other manufacturers, so all SDS+ drills are
basically the same. They all have a snap-lock chuck (if it has a 3-jaw
chuck, it ain't SDS) that takes a wide range of heavy-duty drill bits and
tools. Most have a shift lever that gives you the choice between rotary
action on its own, hammer action on its own, or both together - all in a
drill that you can hold in one hand. It makes those old-style hammer
drills look like toys.

The Hilti TE-76-ATC that Rick rented is based on the SDS Max system, the
'big brother' to SDS+, so it's no wonder those ground rods went right in.

A compressor and an air chisel do exactly that, and 16mm rod will directly
fit into most chisels.

Jeff