Suppose Gruntharg the barbarian carries a longspear
and wears spiked gauntlets. He has a throwing axe at his
belt. He encounters two orcs 60 feet away and wins
initiative. For his action, Gruntharg draws the axe and
moves and also readies an action to throw the axe at any
orc that comes within 15 feet. The orcs charge. As soon as
the first orc gets within 15 feet, Gruntharg throws the axe
and kills that orc. After throwing the axe, is Gruntharg
assumed to be carrying and wielding the longspear in both
hands? Thus, does he get an attack of opportunity as the
surviving orc passes from 10 feet away from him to 5 feet
away? (Gruntharg does not possess the Monkey Grip feat
from Sword and Fist.) If not, what are the rules for going
from a one-handed (or carrying) grip to a two-handed grip
for a weapon, and what kind of action is it to change this
grip? Now suppose Gruntharg has the longspear in both
hands when a spellcaster 5 feet away from him starts
casting a spell. The longspear does not threaten the
spellcaster because it’s a reach weapon and the spellcaster
is too close. Can Gruntharg just let go of the longspear and
smack the spellcaster with his spiked gauntlet? What kind
of action is it to let go of a two-handed weapon with only
one hand?
Gruntharg’s action in the first example (throwing the readied
axe) is possible. Presumably, Gruntharg holds the longspear in
one hand, perhaps letting the shaft rest on his shoulder, or
perhaps just letting the butt drag on the ground. This
arrangement leaves one hand free to draw the throwing axe
while moving, which Gruntharg can manage because he has at
least a +1 base attack bonus. (Even a 1st-level barbarian has a
+1 base attack bonus.) As a general rule, if you’re big enough
to wield a weapon in two hands, you can just carry it
(somehow) with one hand.
The second example (an attack of opportunity against the
second orc) is not possible. Holding a two-handed weapon is
not the same as wielding the weapon. If Gruntharg wants to use
that longspear he has been holding on his shoulder or dragging
on the ground, he has to get his free hand on it. This maneuver
is similar to drawing the weapon, but a little easier, since
Gruntharg already has one hand on it. Therefore, it’s a free
action. But Gruntharg can do this only during his own turn, and
in any case, he does not threaten an area with the longspear
when he’s holding it in only one hand.
The third example (smacking the spellcaster with the
gauntlet) is not possible as described. A spiked gauntlet is a
melee weapon, and Gruntharg threatens the area around him
with it, but only when he has that hand free. In the example,
Gruntharg is holding the longspear with that hand, not wielding
the gauntlet. He could indeed just let go of the longspear with
one hand; this maneuver is the equivalent of dropping the
weapon, even though he is still holding onto it with the other
hand. Dropping a weapon is a free action, but you can use free
actions only on your own turn. Gruntharg could shift the spear
to one hand as a free action at the end of his turn, leaving one
hand free to threaten the area around him with the spiked
gauntlet, but then he would not threaten any area with the
longspear.