Edit 30Jan2017: Well, since I posted this instructable back in 2011, many different variations have cropped up that are very similar to my original if not based on it. I think that is awesome if those guys based theirs on mine, and I am glad. I have an updated design that I'll be posting soon to try to keep it fresh. Keep an eye out!
I have looked around the internet trying to find out if someone else makes these like I do. All I can ever find is a monkey fist attached to a cobra weave, or the same with just an extra length of cord. I hope that this helps someone, and that it is as enjoyable to make as it is for me.
1. 1 3/4 inch steel ball ( I used an old mouse ball with the rubber cut off of it.) you can use a larger one, but you'll have to augment the length of cord needed.
2. About 20 feet of 550 paracord cut into 2 10-foot lengths (better to have too much as not enough.)
3. 1 D-ring, or similar item of your choice.
4. 1 shackle and a key-ring.
1. A pair of forceps, or a scribe ( looks kind of like a small icepick.)
Start with a monkey fist knot,
but make sure you do four raps for each side, and instead of only having a short length of cord on one end you want an even couple of feet on both ends when its done.
You will need this to make the handle. Once you have your monkey fist made you'll need to thread the other length under the two middle strands between the ends where the cord comes out of the monkey fist, and pull it through where it is even in length on both sides.
Then you use the cord lengths to make a "Round-Crown Sinnet," which is just a crown (box knot) with a twist....
Practice the round-crown sinnet to see how to make it with the monkey fist. The picture should help as well I hope.
Just make sure that you are tying it very tightly, or it will be floppy. (which is embarrassing... ha ha)
Keep tying, making sure that it is as tight as possible, until your desired length is reached. I usually make them about 20 knots which makes for a pretty good fob / aggressor deterrent for my key chain. when you get to where you want it insert the D-ring and tie two more regular crown knots to lock it in.
Trim the excess off and burn/ smear the plastic before it cools to make sure it won't slip out.
Remember: This is a dangerous weapon, and should only be employed in dire circumstances where there is no other option.
I take no responsibility for any injury that you cause to yourself or others. Having said that........
Thanks for trying out my instructable. Let me know how it works out for you, and if you like it.