Carbon-fiber is thin.

You can NOT just drill a screw into carbon fiber and expect it to stay put. It could not. The fiber is simply too light and thin a wall for any screw to get and hold purchase. SO, you have to put back-plates on any bit of carbon fiber you want to screw screws into. Backplates are little metal thingies that you can rivet to the carbon fiber and screw screws into later.

So, let's go though back-plate installation for the endcap of an aileron. This backplate will be what the control-hinge actually hooks up to!

First, we drill the hole in the aileron endcap:

OK so the holes are drilled! Lame! The walls of the endcap are too thin to screw anything into, the holes are all blocked with flash! Lame! This part is no good at all yet! Notice my grumpy scowl! Trust the grumpy scowl!

No, it ain't hard, or glamorous. We sand off the flash.

Ah! Now I am STARTING to smile. We have 4 clean holes here to mount stuff.

A backplate! We put a backplate in one of the holes, holding it with a temporary screw just to hold it in place.

We then drill teeny little holes toperfectly match the little mounting-holes on the lef t and right sides of the backplate. Whenever we drill a little hole there, we put in a place-holder rivet (at lower right) to hold everything in place.

And so it goes. I keep using temporary bolts to hold the backplates in place while I drill teeny holes for the rivets to grab the backplates on the left and right sides.

And I counter-sink the holes that the rivets will drop into so the rivets sit totally flush for a smooth finish. I left a few rivets on top so you could see them here... theu sit in the little counter-suck holes (picture below) and the left and right ends of the nutplates on the other side (picture above).

And we squeeeeeeeeeeeeeeeeeeeze the rivets into place.

Resulting in the final product, as seen from the inside. See how you could run 4 screws into this thing to mount your aileron, and each screw distributes it's load across 2 rivets, spaced a little ways away from the screw itself?

And from the toher side: Totally smooth. And the perfect place to put the 4 screws that will mount the aileron to the wing.

There are more parts in this one teeny little endplate than an entire horizontal stabilizer!

But this part is strong enough to define an aileron airfoil and mount the aileron to the wing.. and weighs an ounce or two.

Now we grind a little actuater that will hook up to it:

And here it is!