In my life I've learned that the longer road is almost always the more reliable and easy road.
This dart will take longer than the simpler cone but I believe that it will last a lot longer.
You will need:
Wire Coat Hanger
Twisted Cotton Household Twine
Left handed glove (Or a right handed glove if you're left handed)
Goggles are advised though not required. Flying bits of hot metal tend to sting the eyes.
Step 1: Cutting the Shaft
Ok so you want to hold the coat hanger in your gloved hand because it gets very hot. Vice versa hold the Dremal tool in the un-gloved hand.
Cut off each end of the strait piece leaving only the strait piece.
Step 2: The Tip
Put one of the ends on the bottom of the cutting end and twirl it slowly until there is a tip.
Step 3: The Other End
Ok now if you haven't cut any of your body parts off and you have a strait piece of metal you are doing good.
Now cut a piece of string that is two arm lengths long. Well... two of my arm lengths, that's about 128" total. Now cut it into pieces that are one and one half an inch long.
Now cut a piece of tape to a length of about ten inches. Cut that piece in half Lengthwise. Now you have two pieces of tape (again for you stupid people who are probably bleeding by now)
Lay the 1 1/2" pieces of string on the tape as shown.
Wrap the tape around the end of the shaft that isn't pointy. Twirl the shaft to make things go faster.
Now you're almost done.
Step 4: Finishing Up
Pinch the tape so that it is flat. then use the other half of the tape to wrap it tight against the shaft.
You will have to cut the other piece of tape into smaller pieces so just be ready for that.
You're done now. Don't kill anyone.
Step 5: Something Went Wrong.
Now if your dart won't slide through the barrel just pull some of the string out of the center and take up the slack with another piece of tape.
If it slides through too easily then you should cut another piece of tape and add more string to it.
It's easier to take the string away. So if you're in doubt go big or go home.
I'm not responsible for anyone who gets hut while making this. It's your own stupid fault if you decide to lick the dremal tool while its running.
Also, please don't kill anyone with this. Most birds are ok but remember, it's a sin to kill a mockingbird. Don't use it to kill your dog, but that stupid yappy rat of your neighbors is fine. Squirrels are good too, squirrels and chipmunks if you can hit them. And c'mon, cats are just too cute to kill.
Seriously, this is ammo for a dangerous weapon, be smart about using it.
Fyi this is my first instructible. So I would really like your feedback.
I have a few other ideas that I could post here but I won't if this turns out to be a bust.