No double threaten?

[Escheton]

Ok, first off: can you threaten with armorspikes?
second, can keep reach threat with you twohanded reach weapon when you use you spiked gauntlets to hit someone in your turn?
how about with armor spikes?.

provide link, proof etc

[PersonMan]

Only weapons that explicitly say they have reach do. However, it is a move action to pick up a dropped weapon(free action to drop) and I don't know of any other way you could switch weapons between polearm and gauntlets.

Armorspikes can't be used as weapons, IIRC. They only deal extra damage during a grapple. Nevermind, see below poster.

Draw/Sheathing Weapons.

[Biffoniacus_Furiou]

Yes. You threaten all squares into which you can make a melee attack, even when it is not your action. Armor spikes can make a melee attack into adjacent squares, even when you used a different weapon to make your attacks that round.

Let's assume you're wearing armor spikes and holding a glaive, and you have a +11 BAB. There is a kobold adjacent to you, and an ogre standing at reach with you. When you full attack, you get three attacks at +11/+6/+1, so you attack the ogre with the glaive at +11, attack the kobold with the armor spikes at +6, and attack the ogre again with the glaive at +1. This does not take TWF penalties, because that only applies when you're using a second weapon to gain additional attacks beyond your normal iteratives. Just the same, this character makes AoOs at +11, and can use either his glaive or his armor spikes to do so.

You typically cannot use a spiked gauntlet to make an attack if you're wielding a two-handed weapon. It may be possible to take one hand off the weapon, use that hand to make a spiked gauntlet attack, and put the hand back on the reach weapon at the end of your turn, but in this case you cannot use the reach weapon on that turn because you're using one hand to do something else, and some DMs may rule that you cannot switch back and forth in the same round. It is a move action to move an object from one hand to the other, but removing one hand from a two-handed weapon to do something and then placing it back on the weapon has no official ruling as to what type of action it should be, but most will consider it a free action.