@ tpa: Thank you tpa. Really glad to be back at the OFC/BFLG. Very much a hack both musically and repairing guitars, but they certainly challenge my creativity! The work bench I'm using now was my late mother-in-laws kitchen prep table. She wanted me to repair it and keep it, but I was so busy and never able to get around to it. It was the first thing I fixed before I got to work on guitars.

@seesquare: BFLG projects make me feel like a fixated deer standing in the middle of I-35! Maybe not an oncoming train, but perhaps an 18-wheeler? Lol!

Thanks again for the encouragement! So, 24 hours have passed and the bolts have been removed from the neck tenon. Waited another 12 hours and performed a dry run without and with the tenon cover and here's how she looks without it, and...

Here's how she looks with it... You can see that the mortise side of the tenon cover is a bit off dimension. The cover will be secured with Hysol 9462 and will effectively seal these gaps so not a huge problem but definitely not intentional. The bolt inserts in the neck tenon are secured, but a bit proud (intentional), so a circular piece will need to be cut around the bolt holes in the neck tenon to ensure a clean fit.

On a completely different note: This morning, I went out to walk my dogs at a nearby park, and the Sakura trees were in full bloom - just beautiful. Of course, I thought about my Mom and father-in-law, but I also thought about OMA and Bburg. Hope it's not inappropriate to share these here (some O's were included just-in-case).

So, first in memory of OMA (with "Vincent" the '97C he sold to me; even went through the trouble of sending it to Japan):

and In memory of Bburg (with the 1680 he encouraged me to get. It's been everything he said it would be and more):

God rest their beautiful souls. Thanks for letting me share OFC/BFLG.

Hi Al! Thank you for reaching out to me. I really appreciate your condolences and encouragement. I hope you were not severely affected by the AA Flt 5342 accident back in January. You were the first person I thought about when I saw that news.

It really is nice to be back at the OFC/BFLG! Guitar repair isn't exactly supposed to be a "mystery," but this 1115 has thrown me for a loop in so many different ways! I'm convinced the mystery will be solved soon and I'm definitely on track to getting this 1115 across the finish line! Gonna update the thread with a few small steps I took yesterday and today!

First order of business is to mate the neck to the bowl before the neck is bolted back into place. The position is already quite good; but it's not perfect so I took some 240 grit sand paper and covered the back with some thick packing tape and sanded the neck heel to the shape of the bowl. Rough side up and 60 strokes on the left. Repeated on the right and bottom of the heel for a perfect fit!

Now here's all the pieces I'll need to glue the neck tenon cover into place. The bolt inserts were installed a bit proud so the inside of the tenon cover has been routed by hand to accommodate. For this application, Hysol will be used as a filler as well as an adhesive so controlled squeeze-out is needed to fill the gaps between the tenon and the cover. When bolted into place, the large washers will distribute the clamping force to ensure the glue squeeze out is even.

Applied a thin layer of Hysol 9462 on both the neck tenon and tenon cover. Also added the adhesive in the gaps that needed to be filled. Slowly tightened the bolts with equal force (by counting turns) and wiped away squeeze out. Unscrewed the bolts and cleaned the bolts and the threads in the inserts and repeated this procedure three times until the bolts were tightened sufficiently. In this particular case, I lightly tightened the bolts with a wrench (a bit more force than finger tightening was needed to get the amount of squeeze out that I was looking for.

Tomorrow, I'll unthread the clamping bolts, clean-up the squeeze out with an exacto knife, and drill the bowl-side neck block bolt holes from the diameter they're at now (6mm) to 7mm (might go up to 8mm for one of the holes). Whew! That's all the progress I can make for today. Gotta clean up my work station, wash the dishes, clean the bath and enjoy a movie with the wife! I'll never take normalcy for granted again! Good night OFC/BFLG! To be continued tomorrow...

Uh Ooh...so it looks like I missed sharing a pic of the clamped-in tenon cover in my last post so here it is! The bolts and large washers (which will be used with the neck bolts come final assembly time) distributes the clamping pressure over a larger area.

As this is a "no load" area as far as gluing and clamping goes, the bolts were removed after 12 hours. Hysol 9462 is pretty easy to work with up to about 36 hours of cure time. Once you pass that point the stuff gets ultra hard. So sooner the better (past 12 hours anyway) for cutting out flashing and excess squeeze out in a no load area like this.

After removing the bolts and cleaning out the insert threads, my Japanese carpenter's saw was called into service. You all have probably used one of these too, but these things are amazing. Used the cross-grain side of the blade with no downward pressure. All I need to do is concentrate on the cut angle and straightness of the blade. Pull back lightly and slowly and this thing saws any wood (maybe except African Blackwood) ultra clean.

Notice how the Hysol adhesive fills the gaps in the areas that are not perfectly mated. Hysol will bond with the wood and the bond provided by the adhesive will be stronger than the wood itself. This characteristic of the adhesive enables me to cut, chisel and sand the adhesive as if it is wood (again up to about 36 hours of curing).

Did another dry run without using bolts. The upper area of the neck/bowl joint is still a mess, but the messy looking area does not contribute to the overall structural integrity so I might just leave it as is; however, the fit of the fully restored joint is really good especially for a hack like me! Been practicing cutting better dove and mortise/tenon joints and the practice has definitely paid off! Tempted to just use Hide glue without the bolts to see how the joint holds up! Then again, this is a 12 string and the enormous pull of the string tension with regard to this particular guitar is still etched into my brain... Naw, forget the Hide glue; better stick with the bolts! 

Final fitting will need to be done before the fret board is glued on; but the neck looks aweful straight and lining up nicely to the bridge!

COOL! This is so exciting! This 1115 may sing again after all!

Wait, wait, wait... a lot can still happen before this babby is done. Better not get too ecstatic and keep my feet on the ground lest my blissful enthusiasm be the demise of this project! Okay, okay...gonna take a breather. Will be back tomorrow! As always, comments and advice are always welcome!

Thanks for all the encouragement OFC/BFLG Family!

By slowly turning the brad point bit manually, the bit centers itself and makes a clean straight cut. At this point, an electric drill (at least in my hands) is too powerful and can throw the alignment of the bolt hole way-off. Eventually, I settled on an 8mm diameter for the both holes. The necks fit was finalized by sanding (using 360 grit sand paper double-stick taped onto a flat aluminum bar) the bottom and lower sides of the neck's tenon. Proceeded with 10 strokes and dry fit, another 10 strokes and dry fit. After 60 strokes, the neck was ready for a final bolt-on check. Checked the neck's right side fit...

Checked the center...

Ooh...the center is still 0.3mm proud! Just a few strokes with the sand paper... Now, the left side of the neck body joint...

Just a few more strokes and the neck body joint is mated perfectly! Woohoo!

Okay! Now, how does she look with the fret board in place? 

WOW! She's looking mighty good! Let's get a measure of the neck angle...

That looks absolutely perfect! Yeah!

The last thing I need to do now before assemblng the fret board to the neck is to route two strips down the length of the neck from the nut to about the 5th fret and add a pair of CFRP flat-bars to reinforce the neck. However, try as I might, I can't find my CFRP flat-bars! So I guess that means this is a good time to "call it a day." I'm getting awful sleepy, anyway! So thanks for letting me share OFC/BFLG. Good nighty night!

That's looking really good, Ken.

Make sure to measure the scale length before gluing the fret board down.

It should be 25" from the face of the nut to the front of the bridge.

Thanks for the reminder Dan. Since the neck was being restored to its original position I assumed the scale length would be spot on. It's never a good idea to assume anything when all I need is a measurement to verify so...

Thankfully, everything looks to be in order! Now, I just need the CFR strips that I ordered to arrive! Woohoo! 

The CFRP strips have arrived! Perfect timing as I wait for the 1868 nitro-cellulose finish to dry out before wet sanding. Cool! This 1115 had a slightly twisted neck, but once the fret board was removed, the entire neck has straightened out. These strips aren't going to necessarily make the neck stronger or stiffer; but having had a histrory of bowing and twisting, these strips will definitely provide a significant amount of resistance to protect the neck for a long time to come.

I'm going to treat the groove cutting process like cutting two super long fret grooves, so my fret groove cutting saw and other fretting tools will be used. But before the cutting begins, I need to pencil in the exact location of the groove and use some straight aluminum strips as cutting guides. Light duty double stick tape will be enough to keep the guides in place. Here again, my dremel will be over-powering in my unsteady hands so we'll proceed manually!

This fret cutting saw is the ideal tool to make the initial cut for the grooves. Masking tape serves as a depth guide so that I don't cut right through the neck!

Once the ideal depth is achieved, it's time to call my stewmac re-fret saw to action. This will widen the groove just a bit. At this point the aluminum guides are removed; however, the process becomes ultra delicate. If the grooves aren't cleaned often, saw dust will buildup in the narrow groove. Forcing the saw without cleaning or sawing out of line could split the entire neck right at the groove. Straight strokes and brush/vacuum often!

The fret slot cleaning tool helps to clear out the groove right up to the square edge. Again, digging in too hard, too deep or too crooked can be disastrous!

The grooves are cut from the area under the nut all the way to the neck joint. They need to be just the right width for a snug fit. Too snug risks a cracked neck. Too loose will put strain on the adhesive instead of the CFRP strip causing neck instability! Just right and this neck will never over-bow or twist. After about two-hours, both grooves are done without damaging the neck in any way. Yes!

Now it's time to glue the CFRP strips into the grooves. The CFRP strips are a permanent installation so I'm going with Hysol 9462 again. Need to get plenty of glue in the groove to make sure there are no air pockets that might hinder structural integrity. The adhesive is applied in the groove and on the strips. The strips are pushed in and pulled out several times to ensure glue is in the groove from end-to-end. Wipe the initial squeeze-out, lightly hammer the strip (I hammered on an aluminum strip with the same width as the CFRP strip) down into the groove so that the strip is slightly lower than the top of the neck. Wipe the rest of the squeeze out, and voila!

It's really important to make sure the neck is absolutely straight, once the strips are glued into position; and because of the thixotropic (a word I learned here at the BFLG!) nature of Hysol 9462, the assembly need not be clamped down as there is no load being placed on this glue-up. Also decided to fill the two non-sensical holes drilled on the left side of the neck with 9462 - just don't like invisible air pockets. 

Cool! The fret board will be glued in another 48 hours! Not sure if I'll use Hide glue or Hysol 0151 for that application, but we'll cross that bridge when we get there! Getting closer and closer! Thanks for letting me share OFC/BFLG! Will be back in a coulple of days!

LOL! When you talk about the USFC are you referring to the USAF?

Thanks for all the encouraging comments OFC/BFLG! The adhesive has cured and the CFRP strips are firmly in place so it's time to glue the fret board on to this neck! Exciting! The first order of business is to drill the fret board positioning hole into the truss rod cover strip to ensure the assembly doesn't move around after clamping. Working manually again. 

In this particular case, one positioning dowel is enough, and it will be shaved down for a shallow fit. To ensure the hole is drilled in the right place, the position dowel was super-glued into the fret board and some black paint was dabbed onto the position dowel and dropped onto the neck. Imprecise positioning will = poor intonation.

Fret board position and fit is verified over and over to ensure a perfect match. The pic below is one of many dry-runs that were performed before applying the glue...

Clamp position and caul position (for clamping the fret board extension) needs to be verified. These dry runs also helped to identify some fitting problems that need to be corrected before glueing begins. It's pretty clear that the edges of the fret board are not flush to the neck. Some of this comes from a previous poor fret board removal job. In a few areas, the fret board edges appear to have curled upwards ever so slightly. This fret board was removed 10 months ago so there's a good chance that she's dried out. Thought introducing lemon oil to the center of the exposed side of the fret board might help, but couldn't risk any potential for poor adhesion either! A one inch strip down the middle of the underside of the fret board was sanded down to improve the fit. For this application, Hysol 0151 was called into action and copious amounts of the adhesive was applied to the top of the neck, bottom of the fret board and the neck extension area.

Spent quite a bit of time wiping off the squeeze out; and now, the 72 hour wait for full cure begins! Thank you for all the kind comments and encouragement OFC/BFLG! Hoping I'm just a refret away from resurrecting this 1115!

Yes. With a couple of exceptions, Lyrachord in it's many iterations is FRP.

More importantly, CFRP is stiffer, meaning more resistent to distortion than metal or wood, not to mention lighter than either one.

That being said, theere are times when a maleable material is more desirable than an inflexible one. Many years ago I flew RC model jets. One of my flying buddies was also an innovator who liked to take existing kits and modify them to suit his goals. On one model, a large Blue Angels F/A-18, he used an aluminum spar instead of a CFRP one. One time, he pulled a few too many G's and bent the spar, which introduced a noticeable dihedral into what should be a flat wing planform. Because the spar only bent instead of fracturing, he  saved the model instead of crashing it, which would have resulted in a total loss of his time and money.

Phew! I'm very glad to see you used 0151 instead of hide glue. (HG)

HG can only be used on virgin, bare wood glue joints. It is the only glue that forms a chemical bond with the wood. All other adhesives form a mechanical bond. (you did rough up the mating surfaces, right? I know you did. J/K LOL!)

Yup! Roughed up both surfaces, Dan! Thanks for the advice as I didn't know HG was only for virgin bare wood glue joints. I started working with HG only recently after getting quite accustomed to using Titebond Genuine Hide Glue. The limited working time for HG is just too intense for my slow progress. It took me some time to get used to using TGHG; but the more precise my jointing cuts became (whether mortise/tenon or dove joints), the better the stuff worked. Think I still need a lot more practice before I work with HG on an actual project. Hysol 0151 has plenty of open work time so I was able to progress at a comfortable pace.

Whenever frets are installed, I'm always concerned that the manual pressure I apply might be inconsistent across the length of each fret causing frets to rise out of their slots in various places. This is especially a concern for me when redoing a re-fret (like with this 1115), where the slots might be just a bit loose so while waiting for the 72 hour cure time, I decided to make some fretting cauls. The cauls were made from sliding door wheel mounts and hard rubber plumbing washers.

After thoroughly cleaning out the fret slots, the frets are hammered in. Then they're clamped into place using the cauls. CA glue is introduced on both edges of the frets. By using two cauls I can keep the work moving forward without waiting. After installing all the frets, CA is wicked under the frets on both sides. Incidentally, one of my tuning pegs fell off as I pounded the frets into position. I thought I lost two of the mounting screws, but after searching around for 30 minutes, I finally found the screws. Plugged up the mounting holes with some toothpick tips as seen below, re-drilled and screwed the tuning pegs back into position; and we are ready for a preliminary test!

Fret installation with the cauls went so well that almost no fret dressing needed to be performed before stringing this baby up! At this point, I wanted to make sure that any work performed on this guitar here after would be worth it. No sense putting in all the effort if the neck was going to collapse under tension. So, I strung her up with extra lights expecting to hear some crickity, crackity, crack sounds all the while thinking, please don't collapse, please don't collapse, oh please don't collapse!

Okay, so far so good! To get this 1115 set-up well enough, I needed to add 2 shims under the bridge saddle and one shim under the nut. Some thin Holly veneer was used to make these shims. A classical guitar builder taught me that although Holly is a hard wood, it compresses ever so slightly enabling it to mate well with whatever material sandwiches it. It might just be my imagination, but my Os sound a lot better with Holly shims rather than the shims that come stock from the factory.

Now it was time to adjust the truss rod! When, the new two-way rod was installed, I didn't leave a whole lot of space between the end of the rod and the inside of the neck block as seen in the pick below.

The end of the long truss rod bolt is nestled about 2mm inside of the nut-end of the rod. The picture above shows about a 1mm space between the butt-end of the TR and the inside of the neck block. That means if the tightened TR moves more than 3mm, it will protrude right into the neck block. Over-tightening of the TR could introduce structural compromise in the neck joint. The line drawn at the top of the TR adjustment (pic below) will show me precisely how much the TR has moved after tightening. If the top of the adjustment nut needs to move more than 3mm, the neck will need to be removed and a channel cut into the neck block to accommodate!

However, just after an eighth of a turn, the neck was straight and unflinching even when the guitar was tuned to concert pitch! COOL!  After adding the 3 shims and performing a general setup, the neck seems to be resisting string tension quite well! String action for the 6th string at the 12th fret was right at 2.1mm. For the 1st string at the 12 fret, 1.8mm. VERY COOL! The JLD Bridge Doctor  remains installed so I was expecting the sound board to be pretty dead; however, to my great surprise, this guitar's voice was loud and articulate! Amazing!

I'll still need to correct some cosmetic flaws like the finish on the back of the neck heel...

and head stock...

I'll also need to decide if I'm going to replace the bridge altogether or find some other method to reinforce the area around the string balls. In my previous attempts to salvage this instrument, the top of the bridge was shaved significantly no doubt weakening the structural integrity around the string ball receivers. Afraid the string tension might crack the bridge right where the string ball receptions holes are. For now, this 1115-1 will be strung up, tuned to concert pitch and be left for 48 hours! YES!

The end of this project is finally approaching! After the cosmetic stuff mentioned above are corrected and this guitar stays in its current state for 48~72 hours, a final tweaking/setup will be performed, final thoughts will be written and posted here and we will be done! Of course, I'll need to make and install one of seesquares SK-M pre-amps into this guitar before it's all over too!

Thanks so much for letting me share my journey here at the OFC/BFLG! See you all in a couple of days!

Needless to say, I've now turned the TR back and forth many times and the neck moves predictably without applying excessive force. The low profile two-way truss rod is really a nice product! As a matter of fact, in its current state I'm pretty sure this guitar will handle up to regular gauge strings quite well (might try light gauge at some point). Primary concern now will be the thin bridge.

Look how thin the area above the bb and ee strings are! Personally, I like the low-profile look of the bridge, but I get the feeling that the tension of regular gauge strings (maybe even light gauge strings) might blow the bridge away. Thinking about gluing in (w/ Hy9462) a CFRP strip where the string balls apply the most pressure. Instead of using a unidirectional fiber CFRP strip (like I did in the neck), a properly positioned and glued cross hatch CFRP strip should provide the needed support; AND the CFRP strip will cover the ghastly gouge that I so skillfully rendered to the bridge when I was trying to get the original middle bridge mounting screw out! Lol!

In any event, this 1115 is definitely on its way back to health. Just gotta stay focused and move through each restoration phase slowly... OFC/BFLG support continues to provide momentum to the finish! Thank you!