Browsing the CD-Swap I found THIS POSTwhich left me wondering just what a Servo Horn is.
I would gladly give away any to the person requesting it if it was cool with my team & I knew what it was.
They are the plastic or metal “horns” that go on top of the splined servo output shaft.
They come in a variety of shapes and sizes and are used in many applications varying from rc cars to rc helicopters to robotics, etc.
http://www.modelhelicopters.co.uk/acatalog/jrc46016.jpg
http://www.modelhelicopters.co.uk/acatalog/jrc3125.jpg
Those of you into onmi wheels… should see this
Another type of servo horn is what we call servo savers. They are basically servo horns, but they allow the horn to give via springs or similar mechanism so that the servo gears do not break. They are commonly used in radio control steering.
In the kit of parts you should find them in the servo boxes.
I will gladly accept anything anybody has to offer (or pay for it, it really doesn’t matter).
But specifically I am loking for something like shown on this servo.
If you are wondering why, it is because the servo mounts I ordered from there are spaced up high enough from the mounting surface to lets that horn rotate without hitting anything.
Right now I have the standard + horn which hits and made me have to space up the mounts which makes the whole assembly that much less efficient.
A Servo Horn is part of the Servo Brass section and usually sits to the right of the Servo Percussion section. 
You don’t have a hobby store nearby? I can send you a small round servo horn if you want. Is it for a standard Hitec servo? PM me.