What exactly do you need for the guy who says he can make things out of metal or other materials? Im talking about the guy in Amkethran that is near the big train like looking machine (in the house).

WARNING SPOLIER ALERT
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.The other guy makes you the Big Metal unit.

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As stated by Helspanth the guy can make you the Big Metal Unit.
In order for him to make it for you, you need the Bronze Pantalettes, the Silver Pantaloons and the Gold Pantaloons. Look back further in board archives to find postings about the locations where to get them because I only recall the Golden Pantaloons from coming over from BGI.

And by the way, welcome to the board

I only found one Pantaloons, in abzigail lair I think, where are the others, and the final thig is good?

The Golden pantaloons are from BGI where a noble in the friendly arm inn gives a pair to you think you are the cleaning boy!
The Silver pantaloons is your ransom for the kidnapped lady in the bridge district of SoA.The "man-in-red" quest.
The complete "set" gives you the big metal unit.A joke actually but a really powerfull joke!!!! :D