Took my chisel and thin exacto knife and cleaned around the truss rod. Took Dellef's advice and cleared a relatively straight and flat area upto the fret board.

It was a bit difficult to get at the area behind the fret board, but patience definitely paid off here! Took my mini-file and 120 grit sandpaper and we're good to go!

Now, I just need to decide what material to use as an insert. Carbon fiber, aluminum, Ebony, African Black Wood or something else?

Quite a project you've got going, Ken.

Personally, I would use a bronze bushing.

I've used bronze wheel bushings off R/C cars for bottomed-out TR nuts that needed spacing.

The nice thing about R/C car bushings is that they have a small-ish outer diameter and a large-ish inner diameter. They're also thicker than a washer so you'd only need one.

This allows them to fit over the TR and stay inside the TR cavity in the head stock.

Here's a couple of photos of a sintered bronze bushing I used on a 1617 I re-topped. These particular bushings came from Team Associated and were for their RC10 car. I think these have been discontinued.

I looked on the Team Associated web site and found this bushing set for another car. (Enduro SE)

They don't have any specs, so you'd have to order a set to confirm whether one in the set fits your application.

They also have another set of bushings for their Reflex 14R.

You could also call around to your local hobby stores to see if they have anything that might fit.

Yet another possibility would be R/C airplane wheel collars and for the same reason -- large hole, small outer diameter and thicker than a washer. They are usually nickel-plated brass or stainless steel.

Keep up the good work.

The cut around the truss rod is 1/2 in. (approx. 12mm) in diameter. Since it's been cut flush up to the finger board, my thinking is a 1/2 inch or 12mm anchor would really help spread the load of the truss rod nut over a larger area.  

1). Aluminum shaft coupler:

12mm OD, 5mm/6mm ID, and 20mm L: This will fill the entire truss rod cavity and will need to be hack sawed and ground into shape. Not so sure about adhesion of wood and aluminum.

2). Bronze flange bearing (oil impregnated):

11mm flange OD, 8mm shaft OD, 4mm bore (will need to ream to 5mm). I think this is the stuff Dan was talking about. Thinking a flange would provide better overall stability than a sleeve. Also, the nice thing about a flange bearing is that, I can cut a 1/2 in. OD Ebony dowel, drill a 8mm hole and cover the bearing shaft with some ebony or other wood. This way the flange bearing will be encased in Ebony and will glue into the truss rod cavity more securely. Does that make sense? My only concern was, since it is an oil impregnated bearing, the ebony may weaken over time and crack.

3). Brass flange sleeve bearing (oil-less):

11mm flange OD, 7mm shaft OD, 5mm bore. Same logic as the bronze flange bearing, but this one is not oil impregnated. Might be better than the bronze oil impregnated bearing if I encase the bearing with a wood sleeve.

Ordered all three of the above to test, but thinking one of these will prove to be the Unobtanium! Any thoughts? Will need to wait a week or so for all three to arrive. Meanwhile, I guess I should get started on reinforcing the neck/headstock area. I found out they call this area the "volute" while researching for my reinforcement! Thinkin' it's a good sign that I'm still able to learn...Lol?

Hey OFC/BFLG! Back with some heart break. Yup, in true hack form (just as TPA warned), I broke the truss rod on this beautiful 1115-1. Bummer!

But in hopes that my mistake is not repeated, thought it would be good to leave a record of how I went about attempting the fix... prepare your heart for some guitar carnage ...

Since this truss-rod adjustment exerted unusually high pressure (at least in my estimation), I figured the cavity receiving the washer and nut needed to be as flat as possible so some final prep was performed using a 12 mm dowel with a 5mm bore. Some 60 grit sand paper was double-stick taped to the end.

Just insert the rod and rotate...

Once flatness was satisfactorily achieved needed to select the best flange bearing for the job. The aluminum rod extension cylinder hasn't arrived yet, but these fixtures would be better suited for this project anyway. Bored the bronze flange bearing's (bottom) ID needed from 4mm (L) to 5mm (R). The brass flange bearings (middle) have the right ID, but is a bit long. The larger flange bearing (top) would need to be machined further for a good fit (top) so gonna go with the bronze flange bearing.

Performed some dry runs. Again, recalling to mind the extensive force applied to the truss rod cavity, I decided to add a hard paper plumbing washer (the blue thing) between the wood and the bronze flange bearing in hopes that some of the pressure would be absorbed by the paper washer and spare any wood deformation that might occur (in retrospect, I think this worked very well)...

One final thing was to make sure the string nut fit over the "flange" of the flange bearing. Was originally planning on hacksawing the flange, but decided instead to file the underside of the string nut. Always thought these nuts were bone, but this one was plastic and easy to form.

Then it was time to string her up. Figured this guitar will never wear anything more than extra light gauge strings. DAd's EJ41s are PB and suited to the task. Tightened the truss rod nut to make the neck dead straight, and installed the strings from outside to in.

Once strung, the truss rod nut was tightened as the guitar was tuned to concert pitch. To my surprise the headstock/neck joint was very stable thanks to the truss rod being pulled straight and true. The nut did not seem to be too tight at all and felt easy to turn. Performed a quick set-up and everything was almost perfect. At this point, I was able to verfiy that this guitar sounds magnificent (which bodes well for the future of this guitar)! But then, I thought, "Just one quarter-turn more..." and the heart sinking, "SNAP!" (Warning! guitar carnage ahead...)

After some time, I was able to compose myself and begin the evaluation process (all the time thanking God that this wasn't a friend's guitar!). First thing that jumped out at me was the bronze oil impregnated flange bearing was sweating oil. Took the broken off assembly apart and check this out...

The left is a new bronze flange bearing. On the right is the one I used for this project. Didn't even notice how much this thing was compressing, but I've never seen a truss rod adjustment that could do this to bronze - attesting to my true "hack" status because that just means I was obliviously applying way too much pressure (hence sweating oil)... on the other hand, the neck was still moving as the truss rod was tightened; and IMHO it would have straightened out even more had the truss rod not snapped... 

But the glimpse of this guitar's voice I heard but for a brief moment is enough to keep this guitar in my fold until it is fixed. Thinking there's one more thing I can try with the exposed threads on the truss rod by using one of these female barrel nuts and a sleeve.

With the right length, the barrel nut can thread into the truss rod and pull it while a flanged sleeve can provide leverage, but then this truss rod pulls with some serious force... might just need to install a new truss rod. What to do? What to do?

In any case, here's to hoping that this information might prevent some future BFLG guitar carnage. Thanks for letting me share my journey. Sorry that this one is so anti-climactic, but it will be back - fingers crossed...

Yikes!

That's a real bummer, Ken. Every luthier's worst nightmare. Like you, I would hate it even more if it were someone else's guitar.

As long as there's enough thread on the remaining TR your barrel nut idea might work.

If not, Stewmac does sell tools to perform this type of repair.

See: StewMac Truss Rod Rescue Tools

You could use the relief cutter to deepen the hole around the TR.

As it turns out, they also sell steel spacers in three thicknesses. Who knew?

Worse case scenario would be having to cut new threads on the TR. They sell a die to cut threads, but it's very pricey.

Thanks Seesquare, and thanks for the encouragement everybody! Will be looking for the right fasteners to see if my barrel nut/sleeve idea is do-able over the next couple o-days. Meanwhile...

@Dan - So assuming my barrel nut + sleeve idea doesn't work, do you think it's possible to cut through the neck block to the truss rod end through the sound hole and pull the rod out through the sound hole? I'd rather not remove the fret board to get to the rod if I don't have too, and these older rods require a concave groove to be cut in the neck with a symetrically concave wood cover to ensure the rod stays curved inside the neck. A cut in the middle of the neck block from inside the sound hole might provide enough access to pull the rod out (there's enough rod sticking out of the headstock to lightly pound it out too), and the hole created in the neck block can be filled (it might not even need to be filled). Seems over all structural integrity won't be compromised? In either case, some welding/threading will be necessary to make an appropriate replacement truss rod (I'm sure nobody sells anything like this anymore!). Your expert advice/thoughts would be highly appreciated - please!

Thanks again for chiming in everybody!

As in opening here:

by removing wood ?