Recliner chair repair.
I have a recliner that has been wobbly for awhile. Not long ago I opened the flap on the back (held down by Velcro) to get any stray jelly beans, popcorn, and change. A sheared off bolt head fell out. As I looked around for where that came from I found that it was part of the support for the reclining mechanism. Fixing that should mean fixing the wobble.
So, first I had to remove the rest of the sheared bolt. Not easy. It appeared to be installed through 3/4" plywood which had a T-nut hammered through. Not so. That T-nut was a special connector that was part T-nut, part bushing, and part rivet. I banged away at it for a LONG time and finally got it out. Trouble is, I couldn't find a replacement. But what I DID find was a thing called an "insert nut". This is a device that is designed to be screwed into wood. It has an aggressive male thread for holding into the wood. Then, it acts as a bushing/internal threaded nut.
To install this thing, the manufacturer provides an Allen wrench shaped hole in one end. You drill a pilot hole and just screw it in. I decided to try on scrap plywood. As it turns out, the Allen wrench needed was METRIC!!! I only had "standard." The first one I tried got stripped. I went to the store and got a metric set of wrenches. Took 2 tries to determine the correct pilot hole size that required a little force to turn the nut in, but not enough to cause it to strip.
So finally, I installed the insert nut in the chair and then installed the bolt. Tried it out. Funny, the chair now wobbles toward the right instead of toward the left like before. Why?? Opened it up again and found ANOTHER sheared off bolt on the other side!!! I now intend to replace that one AND THE REMAINING TWO before they shear as well. I do not want to hammer away at that special T-nut again, so I am going to try to use a Dremel, grind a slot into the end of the sheared bolt, and remove it with a slotted screwdriver. With luck, that will work. If it fails, the "insert nut" came as a package of 4 anyway and it will just require more time.