Looking for some suggestions or advice.
This is my daughter-in-law’s rocking chair. The glue and fasteners have dried out and the chair is falling apart. The unit is put together using those threaded inserts for wood hex drive threaded wood inserts.
It appears they were already glued into the wood, and it dried out. Repeated tightening has caused the insert to be stripped in the wood. They no longer grip.
My thoughts were not to replace the inserts but to glue in an oversize dowel in the hole and then use a wood screw to fasten the chair back together. Or should I buy oversized inserts? Or are there any other methods I might consider? 
Chair laying on its side

How it should be attached.

The leg with the holes for the bolts

Leg and cross member

bolts and inserts

 

I'd glue in a wood dowel, use water on the dowel and gorilla polyurethane glue. (Don't get the glue on any of the stained and finished surfaces... use tape to protect any surface you don't want to get it on, because it foams and expands as it dries) After that is cured, (24 hrs) drill the dowel for new inserts, screw them in, then bolt it back together. I assume the half that holds the bolt head and washer is okay?

 

Yes, the bolt head and washer are OK. You don't think a wood screw would do better than the inserts. I'm thinking new inserts will eventually work loose like the first ones did. I'm thinking a pilot hole drilled in the glued dowel and a wood screw would expand the dowel just enough to make it hold tight. I'm sure the bolts will work loose as time goes on due to winter dryness and constant use. The wood screw can be tightened and even a sliver of wood can be inserted to keep them tight.

 

Threads are threads. Why do you think a wood screw would hold any better than a threaded insert? (Except that it might be longer?)

I would do as XSleeper suggested and put a dab of epoxy on the external threads of the insert when you put it back in. I would not use Gorilla glue instead of epoxy for that since it may not have sufficient shear strength with differing materials (wood chair, metal insert.)

Has the chair been dis/re-assembled much? I don't see how "normal" action of humidity changes, etc. would cause the insert threads to pull out. However, overtightening the bolt could. Is there a lot of side pressure on the chair arm?

 

Yes, the chair is used a lot. But no more or less side pressure than any chair might have. But in my experience winter's dry air (especially forced hot air heating) can wreak havoc on most wood furniture, especially after several years of expansion and contraction. And that is exactly why people tend to tighten and re-tighten furniture screws until they strip out. That's why we install whole house humidifiers.

I may be wrong, but I figured that an aggressive wood screw with many threads would have better biting power than an insert with just a few threads. And if it should strip out you can always put in a toothpick or two to tighten the screw, you can't do that with an insert. Plus, the fact that you are now introducing two places for possible stripping out. And once the insert is glued in, if it should dry out it's a bear to remove. As was the case with these two in the picture. They spun, but the glue kept the units from slipping out.

The more I think about it the better an aggressive wood screw appeal to me. I'm not a fan of those inserts for wood furniture. They always seem to fail sooner or later. I have seen many old pieces of furniture that have only used wood screws. And they can always be repaired in quick order. But many "newer" wood (and processed wood) items that use inserts are a hassle to repair.

I think I'll go with my original wood screw idea. But thanks to you both for your input.

 

The chairs may have come from the factory "knocked down" (unassembled) to lower shipping costs; weight versus volume. Both manufacturer and dealer could warehouse more chairs in less space. Machine screws would allow the dealer to quickly assemble chairs as needed.