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Location: Denmark | arumako - 2015-10-16 11:17 AM
I'm still debating whether to go with the tapered steel inserts or the straight ones...
Tapered might tend to split the two-piece neck ...? |
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Location: Yokohama, Japan | tpa - 2015-10-16 7:12 AM
Tapered might tend to split the two-piece neck ...?
I was kind of thinking that too. Straight steel inserts it is! Thanks "tpa"!
Edited by arumako 2015-10-16 5:50 PM
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Location: Pueblo West, CO | Buy extras to practice with in pine boards. You want to make sure you have your technique down pat before attacking the guitar. |
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Location: Yokohama, Japan | Thanks DanSavage! Took your advice and tried the tapered steel inserts. Made sure I was emulating the wood grain of the neck accurately. They worked great on pine (kind of a softer wood I think), but when I tried them on some maple blanks that I had laying around, the wood split. Yikes! I'll definitely need practice with the straight inserts as well before tackling the neck...if I've learned anything from your threads, details, details, it's all in the details! Great fun this BFLG stuff is... |
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Location: Yokohama, Japan | Had a chance to spend a few minutes movig forward again, and was able to fill the cavity with the casting resin. The stuff is pretty impressive, and hardened quickly. I am leaving it over night just-in-case. 
To get more practice with the inserts, I tested 3 different M6 types. Inserts "1." and "3." are screwed into position with a 6mm alen wrench. Insert "2." is hammered in; 1. A short collared and tapered insert, 2. A short hammer-in straight insert, and 3. a long slightly tapered insert as follows; 
This is a strip of Alder. All three of these require an 8.5mm tap for the inserts to perform at their best. The short tapered insert went in nicely, but the collar makes a flush fit in the neck joint a little problematic. You can see that the hammer-in insert just cracked the wood even with the 8.5mm pre-tap. This one is obviously for softer woods? The long insert with a very slight taper fit very nicely. The fit was tight and reliable. If I pour some ZAP thin CA glue after installing the inserts they should hold extremely well. So...steel insert #3 it is. I also am narrowing down my final bolt length choice. I originally figured I would go with the M6 4.0cm bolts, but with steel insert #3, I may not need my neck bolt to be so long. Took out a few 3.5cm and 3.0cm bolts from the tool box to test against the 4.0cm bolts. Just taking small steps forward at a time!
Edited by arumako 2015-10-17 10:26 AM
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Location: Yokohama, Japan | Made just a bit more progress, albeit in an unexpected direction. After thoroughly studying the neck geometry and alignment, I found that the neck was not aligned correctly (probably compromised when the failed neck reset was attempted. The neck was not aligned properly with the bridge and it was off-center by about 1.5mm to 2.0 mm. 
So I had to change my strategy, and attempt a simpler procedure that would enable me to install the neck with proper alignment. I filled the entire neck joint in the SSB with the casting resin and leveled it into shape using my trusty Dremmel. I think the proper repair method would be to use wood inserts and wood shims to refit the neck, but my main goal for this project is to experiment with the Smooth-On Black Onyx product to see if I can use it to repair my Elite 1868 Bowl. If this stuff has good adhesion with Lyrachord, I should be able to substitute this casting resin for G10, and it will probably be an easier fix, but then that's another project... 
I completely cleaned up and rebuilt the neck joint in the bowl, and have it prepped for final routing of the neck block, mortise joint and drilling of the neck bolt holes. Here's a closer shot that shows the subtlety of the skewed neck alignment. 
Progress has slowed down some, but I'm hoping to get this thing done by Thanksgiving! Can't wait to hear what she sounds like!
Edited by arumako 2015-10-22 11:19 AM
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Location: Pueblo West, CO | It's interesting that you completely filled up the neck block.
When I made my suggestions, I had envisioned using the neck dovetail as a male mold to build/rebuild the female dovetail in the neck block. That's why I suggested the mold release on the neck dovetail.
How soft is the molding compound? Will you be able to route it out to accept the neck dovetail? |
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Location: Yokohama, Japan | Yes, I planned on using the male dovetail as a mold to rebuild the female dovetail, but when I tried to make a bunch of dry runs and set the neck in the right place, I couldn't get the positioning correct. After taking measurements, I found that either; 1). the bridge was glued onto the sound board at a slight angle; or 2). the entire female dovetail was fabricated "slightly" off the mark (about 1.5 to 2mm). In either case, when I draw a 90 degree line from the center of the bridge toward the nut on the neck, I don't hit center of the female dovetail.
I always thought that the female dovetail was already part of the lyrachord bowl mold, but perhaps in Asia, they actually cut the female dovetail into the bowl manually? That doesn't sound right, but a misaligned female dovetail seems to suggest that may be the case...anyway, after a bunch of dry runs I couldn't get the neck to settle into the correct position. So, I figured I needed to change my strategy. Of course, I did a bunch of small trials with the casting resin, and got a feel for it first.
The Smooth-On resin product is actually very low in viscosity when you first mix it. It gets hot immediately, but will pour into any crevice like thin CA glue. After a few minutes it starts to get slimy then it becomes like a gel until it finally hardens...all in a matter of about 5 to 10 minutes (depending on the amount used). The spec sheet says it hardens to a shore D rating of 80 (which is pretty hard for a poly-resin product) with tensile strength at 5480psi, compressive strength 8760psi and a shrinkage of mere .010 of an inch.
I figured my best bet to get correct neck alignment would be to simply fill the female dovetail completely and route a mortise joint into it. So, after it hardened during my trials, I drilled, sanded, etc. and the material is quite impressive. The dremmel works like a dream on this stuff after it dries completely. If I route my neck block and mortise joint accurately, I should be able to get fairly good alignment of the neck.
On the other hand, I'll need to work the heel of the neck slightly where it joins the bowl as well. The previous work on this guitar left the neck's heel shaved down more than it should have been. I think I can probably use this Smooth-on stuff to make a shim to thicken the heel by about .25 mm. "tpa"s comment about intonation is turning out to be prophetic!
Edited by arumako 2015-10-23 4:32 AM
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Location: Pueblo West, CO | That makes perfect sense.
Of course, you could always just do the bolt-on conversion like what the frets.com guy did on the Spanish-heel guitar and leave the filler on the body flush, then cut the tenon off the neck. After that, just proceed with the installation of the threaded inserts.
It's the tension on the bolts that holds the neck in place, not the mortise/tenon. I should add that the mortise is molded into the body of the bolt-on Os.
The mortise/tenon on the 1983CE I did had a fairly sloppy fit which allowed the neck to be moved into proper alignment. In fact, it was this sloppy fit that allowed the neck to get out of alignment in the first place which resulted in the high action the owner didn't like. The luthier who'd done the body-swap wasn't very careful about neck alignment when he mated the neck to the new body.
All I had to do to fix the action (once I freed the soundboard extension from the body) was loosen the bolt (just one on a shallow-body O) and hold the neck in proper alignment while I re-tightened the bolt. Once the bolt was tight enough the neck didn't move.
Edited by DanSavage 2015-10-23 9:07 AM
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Location: Yokohama, Japan | DanSavage - 2015-10-22 10:59 PM Of course, you could always just do the bolt-on conversion like what the frets.com guy did on the Spanish-heel guitar and leave the filler on the body flush, then cut the tenon off the neck. After that, just proceed with the installation of the threaded inserts.
That would have been the easiest...but after measuring the steel insert lengths to my neck heel, it's just not meant to be that simple for me...(story of my life)!
But I decided to take just about 20 minutes to start shaping my tenon joint on the neck. I sharpened my trusty chisel again, and practiced on some blanks and made some really good progress. Actually, I was pretty surprised and pleased with the straightness of my first-half of my first ever tenon joint, but... 
I found a nice little hole right where I cut the tenon joint! What in the world is that? 
...Ummm, now that just doesn't look right to me. The USA necks are solid wood (w/aluminum for k-bars), but this one has a hollow spot...actually it looks like it's a hole for a dowel? What the ???... So for now, I'm stopping to evaluate, and try to figure out what this really means. It kind of reminds me of an Ibanez that I repaired for a friend about an year ago with a messed up neck. I had to remove the fingerboard completely for that one, and look what I found... 
...and this one came from the factory like this...yikes! Anyway, I just filled what I can and fixed it up, but I'm sure the Celebrity neck is not this bad. I am worried that the "dowel" hole might go up into the truss rod cavity making it very hard to fill the gaps... Another interesting turn as the plot to repair this guitar thickens! Great fun!
Edited by arumako 2015-10-26 7:06 AM
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Location: Pueblo West, CO | You're certainly doing this differently than I would have proceeded. I would have left the mortise in the body alone. It's got plenty of thickness to take the stress of the neck being bolted to it.
I would have just cleaned the glue off the tenon on the neck so that it could fit easily into the mortise. Then, I would have drilled the holes in the mortise and installed the inserts into the neck.
I'm afraid that chiseling the tenon square is going to weaken the tenon too much. |
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Location: Yokohama, Japan | DanSavage - 2015-10-26 2:08 AM
You're certainly doing this differently than I would have proceeded. I would have left the mortise in the body alone. It's got plenty of thickness to take the stress of the neck being bolted to it.
I would have just cleaned the glue off the tenon on the neck so that it could fit easily into the mortise. Then, I would have drilled the holes in the mortise and installed the inserts into the neck.
I'm afraid that chiseling the tenon square is going to weaken the tenon too much.
I hear ya DanSavage. I might end-up regretting my course of action before this one comes to a close, but I'm not ready to give-up just yet. At this point, filling the hole and reinforcing the tenon are going to be crucial. It looks like I might need to add shims with hysol 9462, and re-cut the tenon before I cut the mortise and install the inserts.
By cutting a clean tenon and mortise, I was hoping to get accurate alignment of the neck to the body. So I was going for a pretty tight fitting neck/body joint. At present, the heel of my neck is not square to the bowl because the neck was off-center. So I need to square that up too. But I must say, I am learning a lot, and I definitely think the Smooth-On resin will be just the right material to fix my 1868 Elite bowl. Hopefully, I'll be able to make a good recovery! |
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Location: Denmark | It almost looks like a peekhole into a cavity that would be stuffed with Kaman bar - had it been a Kaman bar neck. Is it possible to see if the whole corner with the male part of the dove tail is not an integral part of the neck wood but a separate piece glued on?
If this is the case you can remove the block from the neck and cut a new block which you can fit to perfection to the body with dovetail threaded inserts and all and then glue the neck onto the block when everything fits well.
Now that you have made the casting you could also do a little experiment and see if you could machine a joint so you could use the neck from the 1868 with this bowl, if the neck from the 1868 is separate from the bowl - I dont recall. Not that you should give up on the 1868 because that is another nice project. :-)
Edited by tpa 2015-10-26 6:11 PM
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Location: Yokohama, Japan | tpa - 2015-10-26 7:48 AM
It almost looks like a peekhole into a cavity that would be stuffed with Kaman bar - had it been a Kaman bar neck. Is it possible to see if the whole corner with the male part of the dove tail is not an integral part of the neck wood but a separate piece glued on?
If this is the case you can remove the block from the neck and cut a new block which you can fit to perfection to the body with dovetail threaded inserts and all and then glue the neck onto the block when everything fits well.
Now that you have made the casting you could also do a little experiment and see if you could machine a joint so you could use the neck from the 1868 with this bowl, if the neck from the 1868 is separate from the bowl - I dont recall. Not that you should give up on the 1868 because that is another nice project. :-)
Thanks for the observant (as usual) comments "tpa"! I wonder if it is a slot for a Kaman bar. Maybe the Korean made Os from the 1990s used USA style tooling?
I checked the male dove joint on the neck, but it is definitely not a separate glued on piece. However, if Hysol 9462 is as strong as I've heard, then maybe it won't have any problems holding the neck together even if the original male dove tail was cut off and replaced with a separate block of wood. I like the idea of trying my 1868 neck on this Celebrity as well. I didn't even think about that; but then, the 1868 is SSB and this Celebrity Mid-Depth (I think I may have mistakenly called it an SSB earlier in the thread, sorry).
So, in the final analysis, I've decided to shape some hardwood shims and reshape the tenon using as much of the what is left as possible. Extend the tenon, apply the inserts and go from there. Pics to come soon... |
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Location: Yokohama, Japan | Trying to get back on track! The neck is going to take some doing, but I was hoping to get things headed back in the right direction; and so...I made a shim out of alder wood scraps... 
It's shaped to fit over the current male dovetail and I'm hoping with Hysol 9462 filling in the gaps and the steel inserts the block will be able to perform the function of a strong tenon joint. 
Of course, I'll fill up the strange hole with epoxy or the casting resin. If this assembly works, I'll chisel it down to its final configuration and paint it all flat black. Hope this works...wait a minute...I think I'm gonna sleep over this before I proceed! Comments would be most appreciated! |
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Location: Pueblo West, CO | If you're going to fill the cavity with resin, I'd choose hysol over the casting resin.
You should be able use one of these syringes, or something like it to inject the glue.
http://www.lmii.com/products/finishing/adhesives/glue-syringe 
I think the combination of hysol and the steel inserts will do a good job of holding your neck tenon patch into place. |
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Location: Denmark | arumako - 2015-10-27 10:31 AM
... I'll fill up the strange hole with epoxy or the casting resin. ... Comments would be most appreciated!
I'd consider filling the cavity only if it seems to serve a purpose. Also it could make sense to start checking that doing so will not compromise the function of the truss rod. Glued correctly I don't think that your build up wood for the dovetail will be less worthy than solid wood. Actually you have some extra wood for the threaded insert and you have a cross going piece of wood which reduce the risk of splitting the neck in the middle. It could be interesting to look down the hole with an endoscope. USB endoscope cameras are available for the people nowadays at reasonable prices.
Edited by tpa 2015-10-27 2:42 PM
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Location: Pueblo West, CO | tpa - 2015-10-27 12:30 PM
I'd consider filling the cavity only if it seems to serve a purpose. Also it could make sense to start checking that doing so will not compromise the function of the truss rod.
Good point. |
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Location: Yokohama, Japan | DanSavage - 2015-10-27 5:46 AM tpa - 2015-10-27 12:30 PM
I'd consider filling the cavity only if it seems to serve a purpose. Also it could make sense to start checking that doing so will not compromise the function of the truss rod. Good point. Hey, thanks for the valuable input! So now, I get to use the mighty Hysol 9462 for the first time on this project! It is so cool to get to learn all this new stuff on the BFLG...and this Hysol stuff is applied using a cool looking glue gun! 
Look out! Hysol applies nice and thick and hardly "runs" at all. Very stable looking stuff...my craftsmanship does not do this product justice, but I applied plenty of adhesive to make sure the glue was overflowing out of all sides and corners, wiped it down and then clamped and rubber banded it all together and then wiped it down just lightly again with a dry paper towel... 
For now, I've decided not to fill the mysterious hole in the neck, but in order to fully get the geometry on the heel assembly correct, I have a feeling I'm going to have to do more shimming and shaping. Now to wait 72 hours! Ooh, I hate waiting...dry quickly, dry quickly! |
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Location: Thredbo, NSW, Australia | Thanks arumako for the update. I've had one small BFLG repair on my 1614, but I'm keeping my eyes open for another candidate as I'd love to try again with something more ambitious.
I've learnt a lot from yourself, Dan and all the other good folk here at the OFC.
Keep 'em coming!
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Location: Pueblo West, CO | If you go back and look at the most recent factory tour video (2007?) you can see the workers use the same glue gun to glue the rosette into the groove. They're using a quick-dry clear glue, but the gun they're using is unmistakable.
Looks good. I know this probably goes without saying, but you did mix the two parts of the hysol, right?
Yes, one of the nice things about hysol is that it's thixotropic, meaning that it behaves like a liquid when being manipulated (mixed, applied, etc.) but behaves like a solid when left alone. As you've discovered, it doesn't run.
Hysol only requires 72 hours to reach 'full' strength. As long as you've allowed the glue to cure in a warm area, after 24 hours you can probably take the clamps off and start carving away.
Edited by DanSavage 2015-10-29 9:36 AM
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Location: Yokohama, Japan | Thanks for the encouragement BanjoJ!
DanSavage - 2015-10-28 11:33 PM
If you go back and look at the most recent factory tour video (2007?) you can see the workers use the same glue gun to glue the rosette into the groove. They're using a quick-dry clear glue, but the gun they're using is unmistakable.
Looks good. I know this probably goes without saying, but you did mix the two parts of the hysol, right?
Yes, one of the nice things about hysol is that it's thixotropic, meaning that it behaves like a liquid when being manipulated (mixed, applied, etc.) but behaves like a solid when left alone. As you've discovered, it doesn't run.
Hysol only requires 72 hours to reach 'full' strength. As long as you've allowed the glue to cure in a warm area, after 24 hours you can probably take the clamps off and start carving away.
Yes, I did mix the two parts very well before applying. The gun is so cool because it issues the same amount of resin and hardener, and yes, I did see that on the video...I suspect 9462 would be too powerful for a rosette!
The "thixotropic" (I'm even learning new English words on the BFLG!) quality of Hysol 9462 is quite impressive...seems pretty toxic though. Just a bit on my fingers and it started itching. Definitely need to use gloves and goggles (or glasses) when working with this stuff!
It feels good to be headed in the right direction again! I won't be able to give this project my attention over the weekend unfortunately; but that is just as well, as I am bound to rush things and mess it up whenever I'm given the opportunity! LOL!
Edited by arumako 2015-10-29 10:51 PM
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Location: Jet City | arumako - 2015-10-29 1:37 AM
Nice Calendar. I had no idea when Patrick picked October that I was going to get to see my guitars hanging on walls in New Hartford. They know the 6 string pretty well. They've seen it twice and had to refish it. I heard white is one of the tougher finishes to do. |
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Location: Yokohama, Japan | Damon67 - 2015-10-30 12:37 AM
Nice Calendar. I had no idea when Patrick picked October that I was going to get to see my guitars hanging on walls in New Hartford. They know the 6 string pretty well. They've seen it twice and had to refish it. I heard white is one of the tougher finishes to do. Your 6 and 12 string Pearl White Elite pair are amazing Damon67. The fact that they were featured on the calendar in the month of the Mother Ship's Re-birth and the fact they were on the walls at NH during the Re-Birth celebration is incredibly poetic and maybe even prophetic (Ooh! goose bumps)! As for me, my enthusiasm for the return of the Mother Ship was fueled by looking at Patch's OFC Calendar everyday in my office! Thanks Patch. The calendar is even my inspiration to get my BFLG projects done right! I can't wait to see more of your picture in the 2016 OFC Calendar Damon67!
Speaking of getting my BFLG projects done right...I noticed that, per Dansavage's advice, the Hysol was completely dry after 24 hours (at least the stuff exposed to the air). After about 36 hours the stuff was hard as nails - very impressive; and so, I couldn't resist trying to make a little progress and ended up spending an hour on rebuilding my neck tenon joint today afterall... I shaved the truss rod block from a width of 3.5mm down to a svelt 3.1mm to make sure the block didn't interfere with the fit on the bowl. 
I tested the truss rod movement and made sure the mysterious hole was not connected to the truss rod trench, and filled up the hole. 
Smooth-On casting resin came in handy again to make the shim to fix the heel. I will still need to shape it for the final fit with the bowl, but I've been able to restore the heel to acceptable flatness. 
The powerful Hysol 9462 adhesive filled all the gaps in my tenon reinforcement perfectly and powerfully and was very easy to work, but much much harder than the casting resin! Just for fun, I thought I'd compare the neck to my 1868 SSB Kaman Bar neck (Haven't gotten around to cleaning it up yet)... 
Very interesting differences in the Kaman Bar USA neck and Celebrity Asian neck! I'll paint the tenon joint flat black to finish her up and practice routing the mortise joint for the bowl on some blank wood. That will enable me to verify final fit and neck position. If I get it right, I can use my "practice" mortise joint as a jig to drill my insert holes in the neck and bolt holes in the bowl. Just a few more steps to go...Woo hoo!
Edited by arumako 2015-10-31 7:53 AM
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Location: Yokohama, Japan | arumako - 2015-10-30 9:29 PM
I shaved the truss rod block from a width of 3.5mm down to a svelt 3.1mm to make sure the block didn't interfere with the fit on the bowl.
Oops...that would be 35mm to 31mm! |
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Celebrity Deluxe CC247 Neck Reset
