Fishing Line Through Servo Horns
For this step, you might want to have a friend hold the body of the tentacle, so that the tail can float freely. Alternatively, you can string the sides up to a lamp, and achieve a similar effect.
Note: This is a long step that requires a lot of patience and tinkering. It's a good idea to take a break before tackling this!
Here is what the assembly should look like, after these steps:
1. Take two opposing fishing line strings that are tied to the middle vertebrae on the tail
You will know if they are opposing, if they are not next to eachother (meaning, there is another mini-hole between them). You can also tell if you pull one, the other string should become looser.
2. String one of the lines through the horn piece on the closest bottom servo. Make a loop-de-loop, so that the fishing line will be temporarily held in place
3. String the next line through the other end of the servo horn, making a loop-de-loop
4. With the remaining two strings from the middle vertebrae, follow the same steps. Loop them to the servo that is opposite of the one you just used.
5. Similar to before, but now with the end vertebrae: Take two opposing fishing line strings that are tied to the end vertebrae.
6. String the lines through the horn on the closest upper servo, and make a loop-de-loop
7. Follow the same step, with the remaining fishing lines from the end vertebrae
Now that all of the strings are attached to their horns temporarily, it is time to tighten them. The tail should be floating downwards -- when all of the servos are in their current horizontal positions. If the tail begins to tilt, then the line is too taught.
Once you get all of the strings to their appropriate 'taughtness', then tie a couple of nots to secure it in place. Use a few drops of clear nail polish on the not to keep it from becomming unraveled.
Here is a close-up of the line through the servo horn (with a glob of nail polish):
The good thing about the nail polish is that if you need to change one of the strings you can use acetone to remove the nail polish. It's quite handy.
The toughest part is done!!! Now for the sprint to the finish line. (Also, you don't need the tentacle to be hanging anymore, so your friend or lamp doesn't have to hold it up now)