1. Bolts that go into metal thread need some blue loctite. Don't flood the bolt with it, just a drop is all that is needed.
2. If a screw goes into plastic then do not apply loctite, it will eat the plastic. Some say use a drop of CA, but I don't use anything on all but a couple of them, the plastic squeezes the screw and it will stay in fine (unless you have a lot of vibration from the engine/fan area).
3. It's a good idea to clean threads before applying loctite.
4. When a metal ball link wears out, it's usually because dirt got embedded in the plastic link and is acting like sandpaper on the metal ball. So just changing the ball will not be a long term solution. You have to change both the link and the ball.
5. Shouldered side of the link balls go on the opposite side of the screw head.
6. Most links have a special direction they go on. Place the link on the ball, don't snap it on, just push it against the ball and notice how far it goes on. Flip it around and try the other side. The side that goes on further is the correct direction. Most of the ball links have a label on the side that faces out. If the link goes on exactly the same amount either direction then it is bi-directional like the Rocket City links and can be installed either direction.
7. Anytime you make up a link/rod (or even adjust one), pull on the link to make sure it is securely on the rod. If you don't have enough threads of the rod in the link or if the hole in the link is to large (due to manufacturing error) then the link can come off in flight. So make sure you check this on each link.
8. When adjusting links, keep the same amount of thread showing on both sides. If you have no thread showing on one side but the other has a lot, then you probably don't have a lot of thread holding the link on. Try to keep them about equal.
9. A tight link is one that does not pivot freely on the ball. The ones in the rotor head area will free up quickly, but the control links don't. Stiff links cause the servos to have to work harder (and drain your battery). Also they attribute to a sticky feel in a hover. This is where you move one direction then back to center, but the heli does not, it drifts in the last direction you moved. To free up the links, there are three techniques. JR sells a ball link resizing tool part #JRP960219 (some like it some don't, mine works good with a little tweaking), you can make your own resizing tool using an extra ball mounted to a rod, then use some cutters to put a couple marks on the ball that will act to grind the excess material from the link. Another idea is to squeeze the links (while on the ball) with some pliers. This method sometime results in damaged links so you have to be careful not to squeeze too hard or to slip.
10. When you open a parts bag, empty it into a plastic bowl. Make sure the container has a curved bottom with no 90 degree corners so it will be easier to get the small screws out. <see below picture>
