I haven't been working on the plane for a bit because I got some type of flu bug and was out from work for four days last week. When I started again I eventually noticed that the threads on the hinge bearing part MD3616M were a bit mangled. I also discovered that half of the first thread in the nutplate was a bit mangled. I borrowed a friends tap and die set and it worked well on the hinge bearing part, but not so well on the nutplate.
The nutplate has a locking feature that is destroyed by running a tap thru it. I had hoped that running it just thru the first thread would clean out the mangled part, but by doing only a partial cut I left partially cut threads and I couldn't get the bolt end thru at all. My only choice was to replace the nutplate.
There is room there in the rudder brace horn for a bucking bar, but I was dreading punching out the remains of the rivets because the stack up is so thick. I've had lots of problems in the past with such a situation. I popped the rivet heads off and the drill start was dead center in the rivet. I then used a #31 drill bit to drill thru the body of the rivet and when I did that with the other rivet the nutplate popped right out. Easy peasy lemon squeezy!
Lesson learned is when you mangle the nutplate threads your only option is to replace it. The bolt threads can be chased with a die though.
Partially drilled out the fasteners using my button head fastener removal tool.
Nutplate just popped off once I drilled thru the 2nd rivet body with a #31 drill.
