Hammer

Hammer (vertical)

Real life examples: Frenzy, Killerhurtz, The Judge, Diesector (partly) RA2 examples: Grog, BEAR, Bushido

A bot that basically uses a electric burst motor to bring down a weapon on the opponent. Can be everything: a bear claw, an axe, a katana...

A hammer is basically better against bots with a vulnerable roof (rammers). It can be efficient against a bot with a lot of extenders and against horizontal spinners if built well.

Side Hammer

Real life examples: Splinter (Robot Wars) RA2 examples: Atom Smasher

Basically, kind of an hybrid between a clamp, a thwacker and a hammer. Rather than bringing down the weapon, it is bringing it from the sides, like a claw closing on the opponent.

This type hasn't generally the damage values of a normal hammer and does worse against horizontal spinners, but can be made invertable then.

If you want your hammer to be damaging, then put several weapons on your hammer head. A hammer head featuring three razor tips is way better than a simple sledgehammer.