So, let's get started! I had already cut the neck piece out by the time I decided to do a tutorial for it, so I faked it in the first picture. But here is what you need:
1. A pair of precision needle nose pliers. You could probably use tweezers as well, but they might not be strong enough.
2. A SHARP XActo or craft knife. You don't want to have to use a lot of pressure for this, because it will be very easy to slip and cut either yourself or the neck of the doll, so make sure it's a fairly new blade on your knife.
3. Beading Elastic - I'm using 1mm here. I used a double loop, but you could probably use something a little thicker and do a single loop. Just don't get anything bigger, or you won't be able to pull it through the neck.
4. Of course, your victim's body that has already been beheaded. You can use this method on dolls whose head pegs have snapped, too!
5. A suitable S-hook. I used the thinner one, but the thicker one might work too, depending on what head you're putting on there. The thin one is a wrist/ankle hook from a ResinSoul MSD. If you've ever ordered spare hands or feet from RS you know they always include courtesy S-hooks with them, so I have a dozen of these laying around.
NOT SHOWN: Some thin beading wire. I had a coil of wire I pulled out of a piece of wired ribbon on hand. You want it to be thin and flexible. You could pull the plastic coating off of a twist-tie if you have some.
I did not get video or pictures of the process because I needed both hands for it, but this is what you are aiming for. You are going to take your super-sharp knife, and push the point of the blade into the small ring holding the head peg onto the neck peg (the neck bone is connected to the... erm... head bone? I have no idea...) CAREFULLY slide the blade through the ring. If you listened to Wolfie and used a new blade, this shouldn't take too much effort. Avoid slicing into the neck itself and don't cut the peg inside the neck. If it's easier for you, cut the top part of the head peg off with some sharp scissors or wire cutters. ONLY CUT ONE SIDE OF THE RING!!! You want to be able to pull it out in one piece, not leave a bit of the ring still in the neck. It will make the next step super difficult and even more annoying than it already is.
Once you've cut the ring, carefully pull it free of the peg in the neck. Don't break it, for the above reasons. If it starts to break, use your needle-nose pliers to grab it below the fracture point. You might be able to use the hair-drier trick to soften the plastic, too, but I didn't need to.
Now get your thin wire. This part is a bit of a pain and requires a bit of patience. You're going to maneuver the wire under the peg and pull it up on the other side. I needed to use my pliers again, to force it up the other side and then pull it through. You might not have as much trouble as I did, or you might find it more difficult. Maybe better wire would have worked better. Either way, this is what you want to do.
Loop your wire around the middle point of your elastic and twist it a LOT tighter than this picture shows haha. I had to retwist mine three times because I kept leaving it too loose.
Pull your wire back out, and the elastic with it. If you used a thicker elastic, you can pull one end through, but I wanted a double loop, so I left it like this.
Tie the knot as close to the peg as you can get it WITHOUT stretching the elastic too tight. Trim off the excess.
I pushed the knot under the peg. This is optional. Put your hook through the elastic loop, and attach your chosen head!
NOTE: If you used a hook like this one, you MAY want to close the bottom half a little bit more.
And a picture of the thicker hook to show you how it looks.
