Yamaha FG260 12-string restoration

[Bizman62]

Twoodfrd is on my occasional list, there's so much material on YouTube that I've had to limit whom I follow to the minimum to get anything else done. I like to watch them in chronological order to see if the information really is solid on a channel that looks good, especially when the performer tells that they has learned a better way to do something they've already shown in previous videos. Crimson was the first I've mostly seen, Rosa is now halfways. PaskMakes is always fun to watch.

[curtisa]

I find that twoodfrd makes fairly reliable, watchable content. Sometimes I don't necessarily agree with some of the decisions he makes in repairing something, but I find the variety of work he posts interesting enough to keep on coming back.

Crimson might have some useful nuggets of info in their videos, but he also needs to self-edit a bit more and get to the point quicker. I end up skipping through a lot of their videos if I ever do watch them.

PaskMakes I've not heard of before. I'll have to check it out!

[ScottR]

19 hours ago, curtisa said:

Told you it was going to get worse.

Dammit boy, that was a hell of a big bite you just took.

Impressive.

SR

[Andyjr1515]

23 hours ago, curtisa said:

Crimson might have some useful nuggets of info in their videos, but he also needs to self-edit a bit more and get to the point quicker. I end up skipping through a lot of their videos if I ever do watch them

 I had to stop watching them years ago on medical advice.  The doctor said, "Well, I hear what you say about the value of knowledge enrichment, Mr 1515, but it really isn't going to help your blood pressure to stand for hours in front of a computer screen, screaming, 'FOR GOODNESS SAKE, BEN, GET ON WITH IT!!!!!!!!'.

[Andyjr1515]

1 minute ago, Andyjr1515 said:

 I had to stop watching them years ago on medical advice.  The doctor said, "Well, I hear what you say about the value of knowledge enrichment, Mr 1515, but it really isn't going to help your blood pressure to stand for hours in front of a computer screen, screaming, 'FOR GOODNESS SAKE, BEN, GET ON WITH IT!!!!!!!!'.

The doctor's banned me from watching Andertons guitar demos for similar reasons....

[curtisa]

Yes! Anderton's is another channel I can't watch for long. Too much faff, not enough focus. And their product reviews contain far too much smoke up the arse to be objective.

Although a few years ago they reviewed a Mesa Boogie Cab Clone speaker simulator where they were less than favourable about the product. They were requested to re-shoot the video to present less harsh criticism about it, which makes for some really cringeworthy, awkward viewing.

[Bizman62]

1 hour ago, Andyjr1515 said:

 I had to stop watching them years ago on medical advice.  The doctor said, "Well, I hear what you say about the value of knowledge enrichment, Mr 1515, but it really isn't going to help your blood pressure to stand for hours in front of a computer screen, screaming, 'FOR GOODNESS SAKE, BEN, GET ON WITH IT!!!!!!!!'.

Actually I liked the long videos and all the digressing! As I was and still am a novice in woodworking I not only learned how to build a guitar, I've also learned some attitude and cross thinking. With the earphones on, viewing my 30" screen I consider the videos as my personal quality time inside a personal bubble. The experience can be compared to reading a book, a skill which according to studies has somewhat vanished during this SMS era. If it doesn't fit on one cell phone screen it's too long... The latest 'What's on the Bench' videos started to be too boring, though, with all the advertising talk. Even on those the student builds were inspirational and worth following.

[curtisa]

With the neck off it's interesting (perhaps if you're a nerd, like me) to see how the neck and body have been constructed. The fingerboard extension came off reasonably cleany, leaving behind the unfinished area of the soundboard underneath. The ends of the purfling of the rosette meet underneath the fingerboard extension where the join can be hidden, but I was kinda surprised how much effort Yamaha went to to get the inner and middle rings to meet as neatly where it wasn't necessarily warranted:

End view of the dovetail mortice in the body shows the binding was taken all the way to the edges. Given how neatly the ends of the binding line up with the shape of the dovetail I'm assuming the mortice was cut after the binding was applied rather than simply hiding the ends behind the heel of the neck. Maybe there's more love that's gone into these old Yamaha's than I'm giving them credit for?:

Looking back the other way at the heel, the saw bisected a dowel running up the block. This looks to have been inserted when the neck was originally made rather than some kind of repair, as the dowel runs all the way up to the underside of the fretboard through the truss rod, and the bottom of the drill hole can be seen at the end of the dowel about 3cm from the bottom of the heel.

The heel on this guitar is a two-piece construction with the bottom two-thirds glued on to make up the full depth of the heel, rather than being one single piece. This saves waste when making the neck, as a lot of wood would otherwise be thrown away after the neck blank is roughed out. There's no scarf joint in the headstock either, so the upper third of the neck defined by the tip of the backwards-angled headstock and where the heel block extension gets glued on would have been the full depth of the original neck blank.

The truss rod is just a plain steel rod running up the full length with a short threaded section at the headstock, where a nut can be tightened to control the relief. The anchor at the body end is this square flange that has been welded on the end of the rod, which sits inside a square cutout at the end of the tenon, preventing the rod from spinning around as the adjuster nut is tightened up. I'll need to cut out and rebuild this broken area that was snapped off when the neck was separated from the body to allow the truss rod to continue being operable:

The neat thing about this truss rod, however is that you can undo and remove the nut at the headstock and just draw it straight back through the neck to make tidying up the broken end of the tenon so much easier:

[curtisa]

With the truss rod out if the way I can just quickly remove the excess waste material to give myself a flatter area to work with. To rebuild the truss rod anchor I'm just going to install a 'pseudo dovetail' shaped plug into the area. As it doesn't act as a proper tenon it doesn't need to be terribly strong or large; all it needs to do is stop the end of the rod rotating uselessly when the nut is tightened. If anything it will actually get stronger as the truss rod is tightened, as the square flange will pull the block harder against the end of the heel. Making the sides of the replacement block vaguely dovetail-shaped will also help in lining up the neck with the body and prevent it shifting side-to-side once it gets bolted back together:

 

[curtisa]

Similar work is done at the body to remove the unwanted broken dovetail tenon. The aboslute size and shape of the cutout I'm creating isn't super critical, rather that the plug attached to the end of the neck fits in the gap:

Once the neck fits back into the mortice it's time to finesse the shape of the heel to match the sides of the body. By temporarily holding the neck firmly in the mortice with one hand and drawing a piece of sandpaper between the two pieces with the other, the profile of the sides gets sanded into the heel for a snug fit. I'm also attempting to apply more pressure on the bottom of the heel to help angle the neck back to meet the string action I'm aiming to achieve:

Periodically I also need to check the neck projection and left-right alignment to see how it's coming. At this point I'm probably good for backwards angle:

But the bass side needs taking down a hair more than the treble, as the cotton thread I'm using to check alignment is starting to deviate off to one side:

A bit more of this:

Yields this:

BTW, if anyone needs a super-quick body clamp for an acoustic guitar, here's how I'm doing it using just a few Quickgrips. Only applies pressure at the edges, fully adjustable to any size or shape and won't damage the finish (just remember to hang on to the body when you release the clamps!) :

[Andyjr1515]

Great work, @curtisa 

[curtisa]

I need some way to line up the neck attachment points such that they'll align with whatever holes I drill into the body, as any misalignment between the two will undo all the work I've done in trying to get the two pieces to meet properly. I could fiddle about with some fancy jig or CNC-up some fancy contraption, but it just seems a lot less hassle and quicker to use some scrap MDF and just do a simple driling template that can be flipped over depending on whether I'm drilling the neck holes or the body holes.

A bit of leftover 6mm MDF makes a decent starting point. By cutting out a notch for the pseudo dovetail plug/truss rod anchor I installed earlier, I can jast slap it up against the underside of the fret board and trace around the heel to get the correct shape to line everything up with. A centre line square to the bottom edge of the MDF keeps everything nice and...well, square:

Then it's just a matter of deciding where to add my drill holes. 20mm up from the bottom and 10mm down from the trussrod anchor seems like a good place as any. Also pays to identify which side of the MDF is which for later on:

By clamping the MDF back against the heel, taking care to line up the traced pattern back to where it was a moment ago, I can sink a couple of holes into the wood to accept my threaded inserts:

And then my inserts can go in. I've wicked in a generous amount of CA around the outer threads, partially to lock them in place to prevent them from being able to back out and partially to give the surrounding timber some extra hardness once it sets. This is end-grain that the inserts are going in to, which is the weakest way to install a screw thread, so every little bit of help I can give it will save me angst later on:

[curtisa]

Flipping the MDF template around I can clamp it on the body using the traced edges of the heel pattern to line it up. By using the same template and drilling through the opposite side, any alignment errors I may have inadvertently made while drilling the holes in the original template, or when using the template on the neck get mirrored and (hopefully) cancelled out on the body:

The original heel block dowel that was cut gives the impression the two holes are off centre, but when comparing them against the edges of the heel profile where the finish stops it looks pretty much bang-on:

The bolts I'm using have oversize allen heads, which makes them ideal for distributing the load across a wider surface. This makes them less likely to end up just burying themselves into the back of the neck block when they're tightened up. They're sold down here as cabinet connector bolts, used for securing chipboard kitchen joinery carcases to each other:

Inside the soundbox. The bottom bolt hole ended up passing through the old sequential ID stamp, which is a bit of a shame. Still, I've got the photographic evidence of what it said beforehand if anyone really gives two hoots about it:

With the neck on and tightened up I can quickly check to see how well the heel/body join has closed up, which looks pretty good on both sides:

And double-check the neck projection and alignment:

[curtisa]

While the neck is still removeable it makes sense to take advantage of it and redrill the headstock for the new tuners. Unlike individual tuners where each one can be freely located, the 6-per-plate tuning heads mean I have to locate the holes as accurately as I can so that the posts don't bind. so it's time for another quick template out of some scrap acrylic sheet:

A straight line scribed across the length of the template allows me to align the tuners up/down along the run of six positions, and a pair of dividers set for 25mm allow me to walk a mark along the line to step out accurate 25mm spacings. The straight line also acts as my centre line for lining the template up on the cheeks of the headstock:

For added accuracy I'm using a temporary fence on the drill press to minimise any forward/backward deviation in locating the template holes when they're drilled, which minimises another potential source of error. Provided the long centre line scribed on the template lines up with the tip of the drill, all I need to do is slide the template left to drill the next hole:

The other thing to be aware of is that the side of the Yamaha headstock tapers by a few degrees, but the holes are drilled perpendicular to the sides. This means I have to tilt the drill press table back by the same amount to ensure the drill bit will remain perpendicular to the headstock edges. A long drill bit in the chuck and a square helps check for the corrected squareness:

 

[curtisa]

The other thing I need is a way to keep the headstock as vertical as possible so that the tuner holes go in straight, so another quick jig is whipped up out of some scrap melamine-faced chipboard. By pressing the front face of the headstock up against the vertical fence while driling the hole will remain square to the top edge:

Some miniature C clamps hold the template in place to drill the inner four positions:

And then use a couple of 1/4" bolts, nuts and washers to hold it in place while the outer two positions are drilled:

The whole process gets repeated to drill the opposite side, remembering to reverse the orientation of the headstock against the fence, as now the taper on the sides goes the other way. Quick check to see if the new tuners will go in:

And then a few minor touch-ups using some tinted varnish to hide the remainder of the plugged/redrilled holes on the inside edges of the headstock slots. It's not perfect, but then the rest of the guitar isn't either:

[Bizman62]

Oh boy! RSW would get a tough competitor should you ever start a video blogging repair shop!

[Charlie H 72]

This has been fun to read through! You gotta be brave to start cutting into an acoustic. Looks like all is going well, and I bet the final product will be a great player. 

[curtisa]

The side effect of resetting the neck angle is that the fret board extension over the body no longer sits at the same angle as the soundboard underneath it, so you end up with a tapering gap the closer you get to the soundhole. It's probable that my first-timedness in this process has slightly bent the fret board extension when I heated it off to begin with, which has possibly exacerbated the issue as well:

I could just clamp it flat against the soundboard as-is and live with the look of the fret board and strings suddenly diverging at a greater rate at the point at which the neck and body meet, but I'd like to think I can do a little better than that. I've taken the decision to insert a tapered shim into the gap to hide the issue. The only problem I have with that idea is I don't have any rosewood scraps on hand to make a shim large enough. The width at the 20th fret on the Yammy is actually wider than the width at the 24th on my scrapped 6-string electric fret board, from which I was hoping to harvest the rosewood to do this. Nor do I have any other similar-looking timber large enough to substitute.

So in the spirit of 'near enough is good enough' I'm going to use some Tas oak and stain it an intense dark brown. It's only the edges of the wedge that will be visible, so I'm hoping any obvious signs of discrepancy won't draw too much attention to itself. I've just cut a 1mm sliver off a random plank I had lying around, attempting to taper it somewhat towards nothing at one end on the bandsaw. Don't mind the holes, they'll be hidden underneath the fret board...

...Or do mind the holes, if you prefer, and know that I placed them there for optimum tonal transfer :

Here's an idea for how to secure such thin bits of timber when thinning down and shaping. I don't normally like the superglue-and-masking-tape method of attaching router templates to wood because it can be a real pig to try and separate the two once you're done, but on thin flexible pieces it actually works pretty well. Apply masking tape to a flat substrate of some kind (in this case some 6mm MDF), attach masking tape to the underside of the shim, apply a thin zig-zag drizzle of CA to one side and press together for a minute or so. Wen you're finished a thin pallet knife worked in underneath the tape will lift it away from the MDF and allow you to peel off the tape from the shim without damaging anything.

A combination of block plane, scraper and sanding blocks help flatten the shim down to the desired taper and thickness. I'm aiming for about 0.6mm at the thick end, over an effective length of about 50mm:

 

Then pop the shim into the gap on the guitar and trace around the edges to work out where to trim it down. Once it gets this thin it's easy to trim it down using a decent pair of scissors:

Then glue and clamp it in place with a flat caul on the underside of the fret board. The melamine chipboard is handy because any glue squeeze-out that gets on the caul won't adhere to it:

 

[Drak]

On 4/1/2021 at 3:08 AM, curtisa said:

but he also needs to self-edit a bit more and get to the point quicker.

I will second and third that motion. Generally don't bother with him anymore, tho he is talented.

My personality is very bull-oriented (sales testing many years ago), and bulls are always right to the point and very time conscious.

We won't waste your time and we don't like our time wasted, as we consider time a valuable commodity.

We generally cannot bear listening to someone who has commode of the mouth.

I still ROTF laughing about the Steerheads, which I latched onto years before I found out I actually am 'that', for real.

[curtisa]

A light sand is then done to make sure that any remaining oerhang on the shim is flush to the edges of the fret board, and some undiluted dark brown stain around the edges gets applied to help disguise the difference between the oak and rosewood. I've also applied a little flat varnish to seal the stained edges as well, primarily because when I glue this back on to the soundboard I want to avoid the possibility of the glue and stain mixing and seeping out on to the spruce top:

I've also applied glue using masking tape to define a 'no-go' border around the edges to minimise any squeeze-out. The tape gets peeled off after aplying the glue leaving behind a well defined buffer zone prior to clamping. It's also a reasonably thin layer of glue which will help not only in reducing squeeze out, but also if I ever need to remove the neck again it won't take much heating to get it to loosen up:

And then reattach the neck via the bolts inside the neck block and clamp the extension back in place. This should be the final time the neck is removed:

[curtisa]

Not quite, dammit:

The glue hasn't separated. There's actually a slight deformation in the underside of the fret board near the soundhole, and the shim has simply deformed to match it when it was glued on. I'm willing to bet with my inexperience in removing the fret board extension I've slightly crushed the rosewood on that edge. It was this corner of the fret board I started working from when initially trying to get it to separate from the soundboard.

I'm not going to remove the whole neck to fix this one little gap, so I'll use a mini shim to fill it instead. This time it is small enough to make it out of some rosewood:

Gluing it is tricky because I can't move anything for easier access, so I just have to mask the area off and deal with any squeeze-out as it happens. I'm forced to working the glue in by using the edge of the shim to kinda mush it into the gap first:

Much better. A little extra tinted varnish applied with the tiniest paintbrush I can find helps smooth the transition between the stained oak and rosewood too. Again, not perfect, but this guitar isn't either. At least the spruce soundboard remained free of any stain throughout this process:

[Bizman62]

Ooh, a major fix followed by a minor fix and the fretboard looks level at the neck joint! I guess I might just have glued and clamped the fretboard on the top, believing and hoping that the spruce and the bracing would retain their original state... And most likely ended up with a bumpy upper bout and a hump at the 14th fret followed by a slope towards the sound hole.

Well done!

[curtisa]

Thanks Biz. On the one and only acoustic I ever made (from a kit, so no credibility points for me) the neck needed some back angle set into the neck block, and I did just what you describe to get around the deviating fret board issue. The fret board is pretty thin and flimsy and bends easily to flatten against the braced top in front of the soundhole and is unlikely to try and counter-deform the soundboard, especially when you've also got the strings trying to convince the neck fold back on itself as well. But it looks daft because its obvious that the fret board suddenly changes projection under the strings as the action increases dramatically above the neck/body join. You can probably get away with it if the amount of deviation you're trying to correct is small, but above about 1mm gap at the soundhole it stands out like crazy.

[curtisa]

Getting to some of the smaller jobs now. As mentioned earlier, the bridge pins are probably not original on this guitar and have probably been replaced at some point in its past. These ones don't consistently sit into the holes up to their shoulders, with some sitting higher than others:

For a one off job I'm not going to fork out over a hundred bucks for the bridge pin hole reamer with the correct taper from places like Stewmac or LMII, nor am I going to purchase a cheap reamer that won't match the taper of the pins, so I need to adapt an existing tool to do a similar job. It just so happens that the end of one of my rat tail files has a taper very close to the profile of the bridge pins. Here's a particularly crappy shot of the end of the file superimposed over the top of one of the bridge pins for comparison:

By inserting the file into the bridge pin hole and turning it anti-clockwise (ie, against the sprial 'grain pattern' of the file teeth, as if unscrewing it) I can gently abrade the bridge pin holes to open them up to the correct taper and size a teeny bit at a time. I'm doing no more than two turns of the file in each pass and checking the fit of the pin as I go:

Each pin takes a minute or two to do. I'm aiming for a firm press fit, but not so tight that it takes significant force to pull the pin back out once it bottoms out on the shoulder:

After about 15 minutes all twelve pins are done:

[ScottR]

14 hours ago, curtisa said:

After about 15 minutes all twelve pins are done:

Nice!

SR