You might want to do this to go that extra step in a project when buying cordage just won't do or in a pinch to make cordage when none is available. It's also rather attractive, especially when you mix colors of raffia. It makes a fairly strong cord that can be used to tie things, string beads, make nets and mesh bags or weave into different kinds of bags, baskets hats shoes or whatever you like. Most of these uses take a LOT of cordage. You will have sore fingers but you will be awesome.
You can also use this method of finger spinning for other fibrous materials. All sorts of plant materials like milkweed, hemp, cotton and cattails can be used as well as non-plant fibers like wool and horse hair.
This is also a good "pocket project". You don't need any tools and you can fit enough fiber in a pocket to keep you busy whenever you have a free moment waiting in line, riding a bus or watching Youtube videos. It gets pretty mindless fast.
Step 1: Get Some Raffia
It usually comes tightly bound in plastic bags or bundles. You can make quite a bit of cordage from a few dollars worth of raffia. I made about three yards of cordage for this Instructable and didn't use a visually noticeable amount of raffia out of the bundles.
For this project I used purple and "natural' colored raffia so you can see how it goes together a little easier.
Step 2: Preparing to Twist
The amount of fiber in the strands determines the thickness of the cordage. You can make it as thick or as thin as you like as long as you keep the strands even. It'll still work if they aren't but it weakens the cordage and looks sloppy. (You will also want to maintain a fairly even thickness overall as you make the cord so as to avoid weak spots.)
Once you have your strands simply tie them in a knot. I like to use an overhand knot but it isn't all that critical.
Step 3: Twisting
In words, Pinch the knot, or the cord once you get going, between between your left thumb and forefinger.
Pinch one of the two strands of raffia between your right thumb and forefinger and twist the fiber away from you.
As you twist, your forefinger will naturally go between the strands of fiber. Continue to hold the strand between thumb and forefinger and placing the other strand between forefinger and middle finger twist the entire bundle bringing the next strand up for twisting.
Simply repeat this action over and over again to make the cordage.
Step 4: Finishing
If you need to take a break in the middle you can use a small binder clip to hold your place.
You can make the cordage as long as you like or need just keep laying in more raffia as you near the ends of the strands. I'll update soon and add a visual of how to do that but it's as simple as it sounds.
Now you can have nice hand twined cord to go with your projects.
Here's another excellent Instructable that shows how to gather and process dog bane fiber to make the cord.