Found a bug
If you create a Great Sword or One handed Sword you can get the Blade of each sword back.
Grabbing a fully crafted Great Sword by the BLADE then using your mouse to hover over the Pole arms grip it will place the blade from your Great Sword onto the Pole Arms, The AI will still think you've created a Great Sword for them and all you have to do is hand them the Lower parts of the Great Sword (Handle and Hand Guard). They will then buy the Grip/Handle and Hand Guard but with no blade attached. So you get your Great Sword Blade back and receive the money from the AI.
Create Great Sword
Grab the Great Sword with your Cursor by the BLADE
Move the Great Sword over a Pole Arms Grip
The Blade will attach itself onto the Pole Arms (You will be left with an Unfinished Great Sword)
Bring the Unfinished Great Sword to AI Shopper
Once the AI Shopper buys your Unfinished Great Sword (Handle and Hand Guard) grab your Pole Arms and deconstruct it on the Anvil to get your Great Sword Blade back.