I need to make a few arrow shafts hollow, they're about 1/2" thick.
Example:

There would have to be enough space in the middle to put iron wire in it (the thickness of an old coat hanger)
I need to make a few arrow shafts hollow, they're about 1/2" thick.
Example:

There would have to be enough space in the middle to put iron wire in it (the thickness of an old coat hanger)
This sounds like a long pencil with a wire instead of a lead. There are a number of videos and pictures showing how pencils are made on the web. What it boils down to is that first you make the holes (grooves actually, since you do it in halves), and then you make the sticks round. Much easier than the other way around.

If you need to make a lot of them I think it will be safer and more efficient to do adapt the pencil manufacturing method to your job.
You'll probably want to split the shafts, create the hole, and then glue them back together. You'll generally lose half the shaft during the splitting, so you'll end up with half as many completed shafts as you start with.
Mark the centerline on two shafts. You'll probably want to use some sort of jig to hold the shafts for this; if you try to do it freehand, even with a marking gauge, it's likely that the line will twist around the shaft to some degree.
Use a band saw to cut the shafts down their length, keeping the blade to one side of the line. You'll want to just leave the line.
At this point, you'll have two half-round pieces, and two smaller pieces. Discard the smaller pieces.
Sand to the line so that the flat side of the shafts is flat and smooth and the profile of each shaft is a perfect semicircle.
Set up a router in a router table with a round nosed bit that's the same diameter as that of the hole you want in the final shaft. Adjust the router table fence to place the center of shaft over the center of the bit. Adjust the height of the bit to the radius of the hole.
Run each shaft half against the fence and over the (spinning) bit to make a groove down the length of the flat side.
Glue the two halves together to make a circular shaft, optionally inserting wire or other desired filling into the groove before gluing. Wrap tightly with electrical tape, strong elastic bands, or something similar to clamp while the glue cures.
Caleb's advice is probably the most practical way to do this. A possible alternative is a special type of drill known as a gun drill that can drill very deep holes.