You'll notice in the video that he cuts a pretty lengthy thread at the end of the truss rod. A lot of it is cut off in the final adjustment, but there's usually some extra thread on the rod that is hidden under the TR cavity. That's what I'm hoping for with this 1115. If there is more thread hidden in the TR cavity, that will give my barrel nut enough to grab onto.

Oh, and like a big dummy I missed the most obvious and most important dimension that differentiates a 10-32 nut from an M5! It's the diameter! Duh! So the feeling that an M5 nut was a bit loose on a 10-32 bolt was not my imagination! An M5 bolt has a 5mm diameter while a 10-32 has a 3/16 in. (4.76 mm) diameter. That means my M5 barrel nut will fit over the 10-32 truss rod threads with a bit of play and may not be snug enough for this application... not sure how I'm going to find a 10-32 barrel nut in Japan. Everything is metric over here! Gotta spend more time researching! Perseverance shall win the day! Well, one of these days - eventually...

pictured below with the broken end of the truss rod.

Interestingly enough I performed the dry-run using this half-inch barrel nut. The dry run verified that the contemplated method was sound; but the barrel nut had to be tightened like I've never tightened a truss rod nut before! A regular minus head screw driver was just not cut-out for this application. Had to use a socket set with a special head to tighten and remove the barrel nut.

When I removed the barrel nut from the truss-rod (during the dry run) the thread stripped! I was really scared thinking that the truss rod threads stripped, but after close examination, it was the threads inside the barrel nut that stripped. Whew! Glad I had the three-quarter incher! However, the three-quarter incher is quite a bit longer. Wasn't sure if the remaining truss-rod was threaded that deeply. Also needed to make a tool to shave the wood around the existing truss-rod to make sure the barrel nut threaded deep into the neck's truss-rod cavity. Took one of the metric barrel nuts that I purchased and filed the end like a saw blade, sharpened the tip, and screwed it onto the existing truss rod tip. Don't have a picture of that tool, but I think you get the idea - shaved the area around the truss rod perfectly. All I had to do next was to add a washer to ensure the three-quarter inch barrel nut fit snuggly. Here's what the final assembly looks like.

A bit primitive looking, but with a whole lot of slow tightening, the neck is quite straight. Don't want to remove it for fear that the threads in this barrel nut will strip too (maybe I'll pick-up a few during my next visit to the US! Thank God for McMaster Carr!). If you look carefully at the picture below, you might notice that the neck on this 1115 is twisted. I didn't notice until I took this picture myself.

Warped necks are impossible to fix, but twisted necks usually twist in proportion to the string tension so they are not impossible to fix. That means I'll need to resurface the fretboard and refret the guitar which is good because I like bigger frets on my guitars. Won't be able (and don't need to) correct the twist completely, but this will give me an opportunity to further ensure the playability of  this 1115 upon completion. Need to stop for now, but I'll be back in a day or two. I should note that the filled cracks in the top have buffed out really nicely and I also needed to shave down the bridge to improve neck angle when string tension is applied. Really learned a lot during this restoration! Oh poopoo, gotta go! See ya'all around!

Thanks Keldon85!

It's as if the string tension is forcing the truss rod to act like a lever. Once the neck settles into this slightly "levered" position, the neck does not move at all whether I tune the guitar down to "D" or tune upto concert pitch! Since the neck/bowl joint is not moving at all, the problem seems to be isolated to the neck and a bowl bend will ruin the neck/bowl geometry - so that's out of the question (don't think I could do a bowl bend even if I had too!). There is a finish crack right under the area where the neck seems to move so when tightening the truss rod, it almost feels like the wood around the secured end of the truss rod (in the heel) is "soft" (for lack of a better term). If that is the case, I'll eventually have to take the fretboard off, repair the truss rod cavity and install a new truss rod - perhaps another project for another day! Meanwhile, shaving the bridge and saddle down to accommodate the slight neck movement would be the easiest solution, so my goal was to bring down string height by 1.5mm across the board. To do this, I needed to shave the bridge down by 2mm and shave the saddle 3mm.

It was really important to maintain the surface angle of the bridge so the process was pretty slow with lots of measurements inbetween starting from 60 grit sandpaper working up to 340 grit (you can see the top of 2 of the 3 flat headed bridge screws). Also noticed that the saddle slot in the bridge was not flat so I took a millimeter off to flatten the saddle slot and took 2mm off the bottom of the saddle. Taking too much off will compromise the string break angle at the saddle so precision was quite important. No power or dremel tools here! My attention then went to the frets. This was one of the scariest fret jobs that I've done! As I lightly pounded the new frets into position (also used CA glue for extra security), the ultra brittle rosette started cracking and falling apart! Two big chunks fell off the underside of the rosette (pictured below) before I wised up and taped the entire rosette down!

The work became a little easier after the rosette incident as I worked through the refret process. The extra time I spent on resurfacing the fret board was really really worthwhile as there was almost no need to dress the fret crowns after installing them onto the fret board.

Now, the only thing I needed to do was cosmetic stuff like 1). repairing the rosette; 2). sanding and finishing the bridge with WATCO oil; and 3). cleaning up the body finish with wet sanding, compounding, and buffing! While my OFC/BFLG "thread write-up time" requires another day or two, I'm really happy to say that this project (in real time) is now complete and my 1115 is singing! Thanks for the encouragement OFC/BFLG!

Thanks Al!

You know I was encouraged by the most supportive folks here at the OFC and learned from the best right here at the BFLG! I just hope this information might help others struggling with a broken truss-rod or cracked finish. Glad to report this 1115-1 Pacemaker Restoration ends on a very positive note!

After installing the frets and verifying the stability of the neck, it was time to sand and buff out the finish cracks. Taped up the rosette and lower part of the fretboard to ensure polishing compound doesn't get absorbed into the fretboard. Started wet sanding at 220 grit, then moved to 340 grit and on to 1000 grit.

Normally at this point, it's best to shoot the top with a thin poly coat before buffing to ensure all scratches are filled and the buffing process does not cut through the finish down to the wood. However, the poly finish on these Os are so thick (about 1mm) and so hard that I felt going right to the buffing stage would be okay. Since I still don't have an authorized (by the Mrs.!) work area, the project moved to an outdoor bench!

Automotive polishing compound works really well on these hard thick poly finishes while the buffing drill pad makes progress considerably faster. There are three abrasive formulas for this compound; 7, 1, and 0.2 microns. The buffing pad needs to be wased and dried after each formula; and after the 0.2 micron buff, I use small hand buffing blocks to clean up the "hard to get to" areas. After about three hours, cramping muscles, and a bunch of mosquito bites the finish was all shiny and clean.  

Before continuing, the walnut bridge was finished with several coats of WATCO oil. I really like the dark reddish color of this bridge.

After buffing, finish cracks are still visible although they are completely sealed and cleated for stability. It may not be obvious in the picture below, but close inspection reveals a thick (about a millimeter) filled crack in the lower center of the rosette. A cleaner finish could have been achieved had I wrapped the body in rubber strappings when I first sealed the finish cracks at the beginning of this project!

The saddle slot and saddle were modified to achieve the lowest possible string action for this 12-stringer. If ever in the future the fretboard is removed and the truss-rod fully repaired, shims can be added under the saddle to raise the string action as necessary.

Finally, the ultra dried out fretboard was cleaned and wiped down with lemon oil twice. Strung her up with EJ41s (at this point this 1115 won't take anything more than extra-light strings), tuned her up and voila!

Not the easiest playing 12-string, but tunes to concert pitch (will tune down for daily use, of course) and sounds beautiful. It's quite loud and responds dynamically to light picking and strumming. It's been a long and arduous journey. The guitar is not perfect, but I'm really pleased with the results. Will eventually remove the fretboard, repair the truss-rod cavity, and install a new truss-rod, but for now this 1115-1 is singing again! YES!

Thanks for for the encouragement and for following this intermitent journey!

Hi Ken,

Somehow I missed these latest round of updates.

Congratulations on getting the guitar to this finished state.

I'm sorry all this work resulted in a guitar that is not 100% playable, through no fault of your own.

From reading through your posts, it sounds to me like the problem isn't with the neck, but with a collapsing top.

There is one potential solution to help get the action lower. It's called the JLD Bridge Doctor.

It's available from Stewmac. The one you'd want is the screw mount.

I have one on my old Yamaha 12-string. While I don't have one on any of my Ovations, I have read of a few people who've put them on Ovations with success.

Mostly I've read about it on the Facebook Ren-Ovation group. I'm not sure if you need to be a member to see the posts.

See: Ren-Ovation Nation - Bridge Doctor

Mike Murphy, one of the FB group regulars put together a YT video detailing how he successfully installed one on a 2058TX 12-string.

See: Ovation 2058TX 12 string guitar bridge doctor installation

Dan

I found a YT video where the guy compared how the guitar sounds before and after Bridge Doctor installation.

See:  Bridge Doctor Effect on Acoustic Tone

I agree with his assessment that the guitar did lose a little sparkle.

Give the choice of a guitar that's basically unplayable due to excess string height and a slight loss of sparkle, I'll take the loss of sparkle.

Also, with excessive string height comes the loss of intonation as you play higher up the neck.

Interestingly, Breedlove guitars come with their version of the Bridge Doctor.

See: Breedlove Guitar Support: Bridge Truss System

This video also explains how the BD should be adjusted.

Wrong! Pulled my straight edge back toward the tail block and a completely different story unfolded! For this measurement I laid the straight edge flush to the right side of the top (meaning the visible gap, 2.5mm, is halved to 1.25mm for each side). That's significant...

But the big mistake I made was the vertical sinking of the top which I only measured when I first got the guitar. I assumed the guitar was strung up when I took the measurements, but review of my old project photos shows my neglect - no strings! Here's the re-measurement I took after reading Dan's suggestion...

The angle makes it a bit difficult to see, but the sink is almost exactly 2mm without strings! Took a similar measurement on the otherside of the rosette with identical results. Since pre/post measurements were taken without strings there is no way there can be any improvement with strings. That means the top sink worsened after the top cracks were repaired (actually would've made sense if I had thought about it a bit more), and that's the amount I had to shave off the top of the bridge! Coinkidink? I think not!

That means I may never need to remove the fingerboard afterall (assuming the current remedy holds)! If I "Doctor" this 1115-1 up it should be back to proper dimensions! It might lose some shimmer on the top-end of her voice, but I like my guitars sounding a bit darker anyway so no problem there!

Been playing this 12er a bit each day since it's been repaired. The string's soft break angle over the saddle makes this guitar feel a bit loose, but it's definitely playable and it sounds just majestic (even compared to my now collapsed and waiting for a new top Fxxxxr F330)! No wonder Detlef and 2wheel go on and on about their 12 stringers! Yesterday I ordered the Bridge Doctor from Stewmac, and my son (remember delivering my highly coveted 1612 to my son, Dan? He's graduated, and employed in the area now) is traveling to Japan in 10 days or so; he'll deliver it to me at that time! Hopefully, I'll be able to avoid intermittency and get this one completely done. Meanwhile, gonna start working on a custom TR cover to clean things up a bit...just a bit more and this 12er might be back to 100% (well, maybe more like 90%)!

Hey, thanks again everybody! Should be back in two to three weeks!
Happy strumming!

While waiting for the Bridge Doctor to arrive, I decided to get to work on my truss-rod cover.

Couldn't find anything that fit perfectly, but found these covers from SCUD.

The DM-802 wasn't long enough so went with the DM-803 which was closer in shape to the original TR cover but too long. In either case, the cover needed to be shaped a bit to fit properly. The barrel nut and aluminum spacer assembly is just a tad proud of the face of the headstock so I'll need to shape the TR cover with a bit of a dimple.

So I started by marking a rough pattern on the back of the DM-803 including a cutting line that will shorten the cover to fit this application.

The truss rod adjustment wrench actually had the perfect contour so heating it up and pressing it into the back of the plastic DM-803 should create the dimple I need. Made a wooden jig with the correct groove width to allow the plastic to stretch and form the needed dimple. Slowly heated the wrench and tested it against the plastic surface (not much heat was needed to help the plastic begin to deform and stretch), then gradually increased the pressure/heat and achieved the needed contour.

Plastic flashing needed to be shaved off. A bit of scraping, filing, and sanding was needed to clean things up too.

The under side of the TR cover is a bit of a mess, but it works as long as you don't look under the hood!

The DM-803 is a bit wider than the original cover so it fits snuggly under the strings. That means I can secure the cover with just one screw (like my '97 Collector's). It's not perfect, but it's much easier on the eyes than looking at the homemade hack solution applied underneath!

Hoping the Bridge Doctor, due to arrive in a week or so, will completely resurrect this 12-Fret beauty! Maybe one more post to cross the finish line!  

Frankly, I'd just as soon forgo the drama, but being the hack that I am, there's bound to be poor judgment, bad execution, and cringe worthy moments along the way. The short version is, the Bridge Doctor is installed and in waiting for test/review 48 hours from now. Details to follow...

The Bridge Doctor is designed for typical flat-top applications; but our beloved O's are not typical flat tops are they! If you haven't checked out the YT videos that Dan shared in an earlier post, I would highly recommend checking them out before installation. I did, and found that a tail piece or something similar would need to be added to my 1115-1 for a successful installation. The BD's tension bar will not hold its position against the tail area of my deep bowled 12-stringer. To ensure the force of the BD's tension bar was distributed as widely as possible (although unlikely, too much focused tension might possibly sever the bowl and top in that area), I opted for a fairly large piece of Hinoki (beautiful, local resonant lumber).

Taking measurements from the outside of the bowl, the Hinoki was contoured to fit snuggly. Measured the lateral radius at 25". The vertical arch was drawn on cardboard using the pencil/washer method. Transfered the measurement onto the wood block and sawed, filed, drilled, sanded and routed away. Until I got this unremarkable looking block of wood...

Pretty nice, aye? Even accomodated for the strap button nut and drilled the hole to allow for the bolt with great precision! Whew hoo! Wiggled this baby into position and found some hinderances that I should have remembered from my first inspection of this guitar...

Not sure what all that wavy stuff north/east of the strap button is... but it's hard and looks like folded fiberglass hardened by resin. Whatever it is, it will not accomodate my tail piece unless I grind away at the bowl... switched gears and decided to redesign the tail piece into a smaller "tension bar catch" or something...

Only problem with this design is that vertical and horizontal centering becomes a bit of a hit and miss proposition! Not ideal, but it beats grinding the inside of the bowl any day! Will need to use the strap hole button bolt as a centering tool and route a center marker on the tension bar catch to make sure I can feell my way to center when I install this into the bowl. Now it's time to install the Bridge Doctor!

These are the Bridge Doctor parts as they come in the package. There are three positions available for the nylon mounting post. Ovation bridges are deeper to accomodate the pinless top loading string design so position "3" (furthest to the right in above pic) is best suited for our Os. Fortunately, the Pacemaker already uses three bridge mounting bolts, and all I need to do is remove the middle bolt, drill for the slightly larger diameter BD mounting bolt (meaning the original bridge bolt that came on the guitar cannot be used to secure the Bridge Doctor into position) and be on my merry way. So I heated the bridge bolt with a soldering gun (just-in-case the bolt and nut were glued together with epoxy or CA glue) and got my quarter inch socket to remove the middle bridge bolt/nut under the bridge and voila...

The bridge bolt cracked! Oooookay... how 'm I gonna remove the bolt now? So let's try screwing the bolt out from the top... no movement! Tried everything I could without damaging the guitar, stripped the flat head bolt top in the process and took a nice gouge out of the bridge and top finish (as seen above)... 

Okay, now I'm really up the creek without a paddle! Gosh I hate drama... took forever to dig through my tools and find my small diameter metal cutting drill bits. Drilling out the bridge bolt remnants was really really scary!

Fortunately, I was able to drill straight and true through the center of the existing bolt. Continue to increase diameter until I got to the diameter I needed! Now it's time for a dry run! Secured the tension bar catch with double stick tape (fit is just perfect!). Secured and positioned the Bridge Doctor. Measured and cut the tension bar to fit my application.

Verified alignment and tightened the tension screw with a 3/16th inch allen wrench. Everything was really stable, so went in for the final installation and everything is holding really well. The strap lock bolt, the precise contour, and the double stick tape looks to be working really well. Probably won't need to epoxy it into position so essentially I'm FINISHED! Wow that was difficult! The installation guide says installs "in 30 minutes!" Maybe for most folks, but for this hack it took days!

It's taken years to get this guitar out of shape so it'll probably take time for this top to get back into shape. Thinking I'll slowly increase the tension on the tension bar over the next 48 hours, then test for playability and sound and see where the pros and cons of the Bridge Doctor are for this 1115-1! That's it for now! Thanks for letting me share my journey OFC/BFLG! Be back in a couple of days!