Step 1: What You Need
-Pen (Kilometrico pens are easy to work with)
Step 2: Cut the Arrow
In this instructable I cut mine down to a reasonable length, but you can make yours as long as you want.
Keep the vanes/nock, so people know its an arrow instead of a mere hollow carbon tube.
Step 3: Take Apart the Pen
On the ink tube, just above where the metal meets the plastic, give it a generous ring of glue all the way around.
Then push it back into the plastic muzzle thing while slowly turning the ink tube, so the glue is evenly distributed.
It is important that you get a tight grip here otherwise the tube will get pushed out of the black plastic bit when you write with it.
Step 4: Attach the Ink Tube to the Shaft
Then push it into the shaft, twisting as you go so only the conical part of the muzzle and the ballpoint are showing
Only write with it when you are sure the glue is dry, otherwise the ink tube might get pushed into the shaft, where it is very hard to extract.
*Sorry, for some reason I cannot drag my mouse on the pictures. I know that it probably would make this instructable easier to understand, but I'm still getting to grips with this thing.