RAW, grabbing a 1-handed weapon in both hands is a free action, as is letting go of your weapons. I also know that it is generally accepted that you can take at least 1 free action (5 ft step) during a full-round action such as spell combat, and that the # of free actions you can take per round is more or less up to your DM's discretion.
Is it possible, as a Magus with a longsword, to do the following as part of spell combat?
- Cast touch spell with 1 hand free, per Spell Combat rules.
- As a free action, wield longsword in both hands (granting you access to 1.5x str to damage instead of 1x, and +3 damage on power attack per pt of BAB lost).
- deliver spell through free melee attack, per Spellstrike rules.
- Take full attack action at -2 penalty per the Spell Combat rules.