The Butt-Wedge

Got your attention, didn't I?

It's technically called an end graft, but it's commonly referred to as the butt-wedge, and, admit it, butt-wedge is more fun than end graft, isn't it?

It's extremely difficult to get the two ends of the sides to meet perfectly at the bottom or butt of the guitar. As you can see, the sides don't even come together on the end block on this guitar. No worry, however, for this is where the end graft comes in.

The butt-wedge gives you a great margin of error, but also serves as a decorative piece. It's one of those parts of building where you get to use some creativity. It's a great merging of form and function.

I'm going to use rosewood for the wedge to match the rosewood bindings, so I find a suitable scrap that's both long and wide enough. I cover it with masking tape so that the pencil lines are easy to see, draw a centerline, and square up lines at either end. I want the top of the wedge to be about 1/2" and the bottom 1", so I draw these dimensions and connect the lines.


After cutting this out at the band saw, I put some masking tape on the end of the guitar and trace this wedge shape onto it, matching the centerlines. I then saw down to the end block just inside these lines using a block of wood as a guide to make sure that the saw blade stays square to the bottom of the guitar. Once these cuts are made I chisel out the zebrawood between the lines, and sand everything smooth.

Now, I'm a dork, and now realize that I made my wedge too short; I should have extended the lines on either end so that the wedge is both too narrow on one end and too wide on the other. That would give me more wiggle room. As it is, with the cut I've made, the wedge is actually too tight before going all the way to the top.

Also, I plan to have two purfling strips on either side of the wedge, which just makes the problem worse. So I find another piece of rosewood, cut a masking tape template from the actual wedge cut and transfer that to the rosewood, extending the lines much further than actually needed. Cut that out, and here's what I get:

Now it fits in the cut with room to spare on both ends. When I do a dry fit of everything I realize that the purfling strips sit just barely below the level of the sides and I want them to be just proud of the surface, so my first step is to glue a thin piece of wood veneer to the bottom of the graft.

I spread glue on this, making sure to get some on the sides of the graft, and then put the purflings in.
Then I slide the butt-wedge in, making sure the purfling strips don't slide forward too much or slip up over the surface. Because it's a wedge shape it serves as it's own clamp; just a couple of light taps with a hammer, and it's in. I use a damp paper towel to clean up the glue squeeze out.


I want to make that the wedge is seated tightly in the cutout, I clamp it down for a few minutes using a wood caul.


After about an hour it's ready to be trimmed and then scraped and sanded flush to the surface.

Losing Hegemony

I know a guy who was a member of my church in Georgia before moving to Nashville a couple of years before we came to Maryland. He’s a very talented musician, and though he supports his family by driving a truck, music is his passion. He is also a very committed Christian, and loves to play and sing Christian rock. He is one of the best guitar players I’ve ever been around, and he hoped that he could break into the music industry in Nashville and get off the road. Alas, Nashville is full of very talented guitar players, so he contents himself with playing for his church and recording his own music.

He includes me among those he emails when he has something new going on in his music life, and such was the case last week. I noticed that he has set up his own website, so I went there to check things out. Then I noticed he had link to a journal, where he had an entry from March about the hard financial times our country is experiencing. What caught my interest was his statement that our financial problems are due to the lack of Judeo-Christian values in America. “This nation succeeded in becoming independant (sic) and strong by adhering to the principals (sic) found in the word of God, and now the word of God is being pushed aside.”

I’m familiar with these sentiments, but they always confound me. There is no doubt that the European countries that started settling here in the 17^th century came from countries where Christianity was the dominant if not the officially government-sanctioned religion, nor is there any doubt that some settlers came here for explicitly religious reasons—to escape religious persecution and to be able to worship and practice according to their own convictions. It is also clear, however, that our country was founded on the principles of rational Enlightenment philosophy, and it is these principles that are embodied in the Declaration of Independence and the Constitution. Where there was overlap was because Christianity of the 17^th century and following more often conformed to Enlightenment philosophy than the other way around. Regardless, it was always an uneasy alliance, for rationalism has little place for gods of any sort. As Enlightenment philosophy grew it would inevitably push out theistic faith. This was seen in the deistic faith of Washington, Jefferson, and others among our founding fathers.

In the first centuries of our country’s existence Christianity enjoyed a dominant position. There might have been a few Jews in America at the beginning, but few if any Muslims, Buddhists, or even atheists. Most Americans lived their lives without ever encountering a person from another religion.

Over time, however, immigration brought people from other lands, and they brought their religions with them. Enlightenment rationalism spread as science gained ascendancy, pushing theistic faith more and more to the fringes of society. Christianity still enjoys a plurality of adherents in our country, but on any given Sunday if you add up all the people in Christian churches and compare that to those who are not, either because people are observing some other religion or are doing something different altogether, it’s clear that we are no longer in the majority.

And I think its losing that hegemony that bothers my friend and many other Christians like him. We’re used to being the majority, and having the power and influence that comes from being in the majority, and as we lose that dominant position we feel that we are losing something very precious.

I’m not so sure. I think a reading of history shows that whenever a religion is able to become dominant in a nation, it’s not because the nation has become conformed to the principles of that religion but because the religion has become conformed to the principles of the nation. Prior to Constantine, Christianity was poor, powerless, persecuted, peaceful—and flourishing. Once Constantine made Christianity the official religion of the Roman Empire, Christianity became rich, powerful, warlike, persecuting—and corrupt. Rome didn’t become more like Jesus; Christianity became more like Rome.

What’s the saying: power corrupts, and absolute power corrupts absolutely. I’d say it is a good thing that Christianity is losing its dominant—and dominating—position. Maybe now we’ll be free to truly follow a crucified Christ.

And We Have a Box

While the back was drying I had one final task to do on the top. The upward pull on the neck by the strings pushes the part of the fretboard that is glued to the top downward. Sometimes cracks can develop on the top at the edges of the fretboard due to this downward pressure. To counteract this Martin has always used a wide, thin brace that ran across the upper bout parallel to the transverse brace. I ran across a website by a luthier and guitar repairman where he showed numerous Martins that still developed cracks in spite of what he calls this popsicle brace. He instead uses a smaller trapezoidal-shaped brace that runs from the heel block to the transverse brace, with it's grain running sideways and perpendicular to the grain of the top. It's wider than the fret board and covers the entire area of the top affected by the fretboard extension, unlike the popsicle brace. A long narrow piece of wood is weaker than a short wide piece, so this makes sense, and I've incorporated it into my bracing pattern.

I didn't glue this piece on with the rest of the top braces because I wanted to wait until the heel block was in place so that I could get a precise measurement. Here's a picture of the brace in place.

I let that dry overnight along with the back. Tuesday evening I unclamped the back; we're halfway to a box!

The trapezoid brace had to be trimmed a bit to avoid the kerfing on the cutaway, and then we were ready to glue on the top. Well, almost.

It's a tradition for the luthier to sign and date the top before assembly. In an ideal world this signature would never be seen because it would entail the destruction of the instrument. It's just kinda cool, you know?

I lined up the centerline at the heel and butt, and did a dry run. I used a thin plywood caul cut in the shape of the dreadnought cutaway I did last year, and though the OM is a little smaller, with a little shifting it works. I want to use the caul because the spruce is softer than the zebrawood, and even with the tips on the fiberglass go-bars, I didn't want to take a risk of dinging it. Plus, if I had to use the bamboo go-bars I didn't want to trust the small pieces of spruce I used as cauls on the back.

The dry run showed me how many go-bars I needed and where I needed extra pressure. I undid everything, spread glue on the kerfing, end and heel blocks, and clamped it all down.

This morning I unclamped it and took it out of the mold, and now we have something that looks like a guitar! There's one more thing to do, and that's to remove the spreaders that were left inside. Even though I measure the blocks to make sure they fit through the sound hole, it's a bit of a tense time. If for some reason the wingnuts lock on the threads and won't move, well, Houston, we have a problem. I guess the only thing to do would be to heat the top or back to loosen the glue and remove it, and then work on the spreader, but I don't want to ever find out the best way to fix that problem. It's a big relief when both of the spreaders are out of the box.

And here it is.
Next up is to rout the edges flush to the sides. After a rough sanding of the sides then I'll start working on the bindings.

Gluing the Back

There was a lot to do to get ready to glue the back and top on. I placed the back on the sides and marked where the braces crossed the kerfing. I have to notch the kerfing at these intersections so that the back will fit tightly. I use my Dremel with a flat base and a 1/8" bit, and measured the depth so that the brace just barely clears.

Then I rout out notches for all the braces.


Now the back should fit flat on the sides, but it doesn't. There's a problem. The bracing pattern that is being used is for a regular OM without a cutaway, but the cutaway on this guitar dips down into where the top brace runs. The brace is rubbing against the kerfing. I don't want to notch the kerfing for the brace, because I need the gluing surface more than I need the support of the brace. In fact, I don't need the brace at all on the cutaway side because the side itself acts as a brace. This area is well supported. So I have to chisel out not quite half of the top brace, measuring constantly until it fits. Then I have to sand the brace again and the surface where the brace was removed.

And then I realize that if this was true for the back, it's probably going to be the case with the top, and it is. I have to carve away half of the transverse brace of the top, before it will fit as well.

That being done, I now have to sand the inside of the sides. I start with 100 grit paper and progress through the grits until 400. This includes the heel and end block. This is a lot of work for parts that will rarely if ever be seen and probably never touched, but it's worth it. It really makes the wood shine.

While I'm sanding I go ahead and clean up the inside of the top. There are a lot of pencil marks from when I laid out the bracing pattern, some of the pencil marks are now under glue squeeze-out, and there are weird angles where it's hard to get sandpaper in with any downward force. I use different sizes of sanding blocks, one as small as 1/2' square to really get into tight areas. I use a razor blade to scrape away the glue in tight places. It's a lot of work, and even with the air conditioner I'm sweating a lot. Eventually it gets clean and looks good.

But that was just with 150 grit paper. I have to do all surfaces again with 220, then 320, and finally 400 grit. I'm dirty, tired and hungry, and about 6 p.m. I call it a day. Pam and I have dinner on the deck then take the beagle for a walk.

Sunday was a long day and I was tired, so I just punted guitar building for the evening.

Monday night I get back to it. I cut some thin strips of spruce to glue to the sides with the grain running perpendicular to that of the sides. Some builders use these struts, and some don't. I didn't on the last guitar except on the tight curve of the cutaway, just to give this area a little more strength to guard against splitting.

I decided to take the time to do this at a couple of locations. If the guitar is ever banged, this will give a little protection against a split developing along the grain of the side.

I glue a real narrow strip in the middle of the horn of the cutaway, then two wider strips adjacent to it, following the curve, and now the horn is really reinforced.


I glue one on the opposite side of the upper bout, and one each opposite each other on the lower bout. Once again, these aren't necessary, and nothing is going to protect a guitar if it is banged real hard or dropped on something sharp, but it doesn't take much time and just might help.

Well, there's nothing left to do now except glue the back on. As alway I do a dry run using the go-bar deck, and it's a good thing, too. I find that in a couple of areas the kerfing wasn't sanded down flush with the sides. I hit these areas with a sanding block, and now everything fits fine.

The dry run also lets me know that I don't have enough fiberglass go-bars. I have 15 go-bars, and that's not enough. Not a problem though: I anticipated this, so on the way home I stop by Home Depot and buy a couple of packs of bamboo garden stakes. They're about 8 feet tall, and their rigidity varies from stake to stake, and along the length as well. But I cut a few, and I'm ready. If it seems like I'm flying by the seat of my pants here, these bamboo rods are what we used at Vermont Instruments and what I used for the last guitar, so it's cool. Unlike the bamboo, the fiberglass rods have consistent flexibility, they don't break, and they have rubber tips so I don't have to use wooden cauls to protect the guitar. But they're a little more than $2 each. I'll buy some more when I have a little fun money, but they aren't necessary.

OK, so I've done a dry run, got everything ready, so it's time. This is an exciting part. I spread glue on the kerfing as well as the heel and end blocks, line up the centerline, and start placing the go-bars.

This gets to dry overnight--or almost 24 hours since I won't get to it until after work. Then it's time to glue the top on, and we'll have a box!

Heel Block and Kerfing

The heel block arrived from LMI, so it's back to the body. It comes as a 1 1/4" x 3" x 5" block, and it needs to be 1 7/8" x 2 3/4" x 3 1/4", but a couple of whacks on the table saw takes care of that.

If this weren't a cutaway I'd be ready to glue it on, but nooooo! Everybody wants a cutaway these days!

Just kidding.

But this is one of the areas that a cutaway complicates. Rather than just needing one good gluing surface, I need two good gluing surface, and one has to be curved. First I trace the curve of the cutaway onto the end of the heel block.

This curve must go all the way down the length of the block, which complicates things. The band saw can be used to hog off a lot of the material, but it's a little dicey to cut things that thick when I'll be holding it by the short dimension. It gets my fingers close to the blade on a thick, curved cut, and I like all ten of my fingers.

So I use the curved end of my belt sander. It's really impossible to put even pressure on the block as I hold it against the sander, so it doesn't remove material evenly down the length of the block. Eventually I decide that the best way to do it is with a chisel. There's a lot of chiseling and checking the fit, and there is no way it's going to be perfect, but it doesn't have to be perfect, I just need the there to be enough of a gluing surface for the cutaway side to have good adhesion. It actually takes about two hours, but finally I'm ready.

As always I do a dry run to make sure I know the best way for all the clamps to be positioned, and then I glue it to the body.

That's a shadow on the other end of the block which makes it look like the block isn't tight against the side. Here's a view from the other direction and you can see that there's a tight fit on both surfaces.


After some time with the radius dishes to get the sides, end and heel blocks down to dimension, it's time to glue the kerfing. The sides are less than 1/8" thick, which isn't a sufficient gluing surface to hold the back and top, so kerfing is used to increase the gluing surface. Also called linings, these are narrow strips of wood that are glued on the edges of the sides. Originally the linings were solid strips that we bent to match the shape of the sides, but at some point little slots or kerfs were cut into the linings to give them flexibility, and eventually the strips were called kerfing.


Most kerfing is glued on the opposite side of the kerfs, with the kerfs facing toward the inside of the guitar. However, a few years back someone experimented with gluing the linings with the kerf-side being glued to the side and discovered that this made the sides more rigid. This is probably because the glue gets in between the kerfs and then dries hard, making the whole strip more rigid. Anyway, since I was taught using reversed kerfing, it's what I continue to use.

It's a simple process. Just spread glue on the kerfing, position it on the side so the end sits just above the edge of the side, and clamp. I use little spring clamps. Unfortunately I only have enough to do one half of a side at a time. It takes about 50 clamps to do all the kerfing on the front or back, and I have about 75. Whatever, it's just time. I start with the back. Here's one side:



I let the glue dry for about an hour, then do the other:


Flip it over and do the same for the top. On tight curves like the cutaway the kerfing breaks, but that's not an issue. I don't need the lining to be tight to itself, I need it to be tight to the side and provide a good surface for the top and back. Here's what the kerfing looks like unclamped:


It's Saturday morning and I just have one more strip of kerfing to glue on. The reason the kerfing is left proud of the edge is so that I can sand the back and top radii on them, and that will be next in the process. After that there's a lot of sanding and cleaning up the inside of the sides so that they are smooth, all pencil markings are gone, and there is no glue drips, because once the back and top are on, there's no going back inside the box.

And we are very close to having a box. Maybe even later today.

Fretboard Binding

The cool thing about building a guitar is that there is always something to do while waiting for glue to dry or for a missing part to be mailed. So the other day I did some work on the fretboard.

First it had to be thicknessed, which is an misnomer because I'm actually thinning it. The blank comes about 5/16" thick and needs to come down to 1/4" or even 7/32". I know that 1/32" doesn't sound like much, but little things can make a difference in playability and hand fatigue.

So I used the jointer and then a sanding block to reduce the thickness. No pictures here, because, really, you don't have that much time, do you?

Ok, next is to cut the taper. The fretboard needs to be wider where it joins the body than at the nut. I already have a posterboard template with the exact scale length and taper, so it's just a matter of transfering this to the fretboard. First I cover the fretboard with masking tape so that the pencil lines will show up clearly, then I draw the centerline on the fretboard. Then I lay the template on the fretboard, lining up the centerlines, and trace the taper onto the masking tape.

I am going to use wood bindings on the fretboard. Not all guitars have bound fingerboards, but this allows the fret tangs (the part of the fret wire that is hammered into the slots) to show. It's not ugly, but a lot of makers like to hide these by melting black lacquer wax on the ends, or by binding the fretboard.

I don't mind the fret tangs showing, but I love the look of a bound fingerboard. It really dresses a guitar up, and I don't imagine not binding the fretboard unless the customer specifically asks for it to be unbound.

Because I want the width at the nut and at the saddle to remain the same, I have to reduce the width of the fretboard by the thickness of the binding material. I'm using rosewood binding, which next to the black of the ebony fretboard provides a subtle yet classy contrast. I'm also going to sandwich a thin strip of black/white purfling between the rosewood and the ebony. The black line of the purfling will go against the fretboard and disappear, leaving a very thin white line. It ought to look sweet.

I use calipers to measure the thickness of the binding and purfling. As you can see, it's .105" thick.I use the calipers to mark this distance in from each taper line and draw a new line. This is the width I am going to cut the fretboard.


I use the bandsaw to cut just outside of this line:

Then I use the jointer to bring it down to the line evenly down the length. Just a bit of sanding to remove the jointer marks, and it's ready for binding.

First I glue the purfling to the binding, then cut a small piece to go on the bottom of the fretboard.

I use masking tape to glue it to the fretboard.


After it dries I use a chisel to cut a mitre on one end:


I then take a long binding/purfling strip and, using a disk sander, mitre its end to fit. Because of the taper it's not a 45 degree mitre, so I have to use a lot of trial and error to get a close fit.

I spread glue on the strip and use a couple of pieces of masking tape to put it in place,


then spring clamps to get a nice, tight glue joint. The spring clamps tend to pull up on the binding, so I use a couple of clamps to hold everything tight to the workbench.

I only glue one binding at a time. I could tell you that my experience says that it's better to have a stable side opposite the glue side, but most people glue both bindings at once. The truth is that in the trial and error of mitering the binding I discovered that the binding was now too short. Luckily I ordered plenty of rosewood binding for just this kind of stupidity, but rather than wait for the purfling lamination to dry on the new piece, I decided to go ahead and glue the one binding and then do the lamination.

After the one side dried I repeat the mitering and gluing process on the other side. I took a picture but it pretty much looks like the one above, so use your imagination to see the other binding being glued.

And here's the result: a bound fretboard.


It still needs fret dots on the top and side, and then I'll sand a 16' radius on the top, but that's for later.

You Know You're Middle-Aged When...

So today I'm sitting at a stoplight when a good-looking blond woman pulls up next to me in a brand-new, shiny red BMW convertible.

I couldn't help but stare. I caught myself thinking, "Wow. Sweet."

And I was talking about the car.

And then I thought, "High-maintenance."

And I was talking about the woman.

Middle-age. It's not a year, it's a mindset.

Moving On

You know what? I was going to use the off-cut from the neck block to make the heel block, but discovered that it's not tall enough by about 1/4". So I had to go on the LMI website and order a tail block, then wait for it to come in from California.

First I called a hardwood store and inquired if they had any Honduran or African Mahogany that would be suitable. Most of what they had was in slab form, and I need a block of wood. They had some big blocks, but the smallest piece they had was going to cost $65, so going local so I could keep going was out of the question. The tail block from LMI costs about $5, so, yeah.

So instead of being able to glue the tail block, then the kerfing, and then attaching the back and top to the sides this weekend, I have to wait.

I hate it when that happens.

But there's always things to do, so I turned my attention back to the neck.

First I started working on the inlay for the headstock. When I first got into this hobby I contacted an inlay artist, Paul Bordeaux, who does some really great work. Check it out here. We traded some emails until we decided on the look I wanted. When it was time, I mailed him the neck to #002 and he inlayed my name in pearl at the top of the headstock. Here's how it came out:Inlay is a skill, but it's one a good luthier should develop for basic stuff like this, so I had Paul cut another logo in pearl and send it to me when he mailed the neck back. I wanted to do the inlay myself on #003, then maybe on #004 try doing it all myself, including cutting the pearl.

So here's the process. I drew the centerline on the headstock, then another line square to that where I wanted the name to go. The logo comes in three parts: the capital E, then the rest of the name, then the swirl under the name. I placed the pieces using the lines as guides. When I was satisfied with the placement I used regular model airplane glue to glue the pieces to the headstock.

After letting that dry for a couple of hours, I used a sharp razor knife to scribe the outline into the ebony headplate.
I then use the knife to carefully detach the pearl from the ebony. I scraped some chalk onto the logo and rubbed it into the lines, and when the excess chalk is blown away the scribed lines show up clearly.
I attach a base to my Dremel tool and insert a very fine bit--1/32" and adjust the depth so that the pearl will be just proud of the surface, then start routing the logo.


There's a lot of stopping to check the fit, but finally everything fits and looks good. I thought I had taken a picture of the pearl laid in the ebony, but I guess I forgot. Here's the finished routing:

I'll mix some black furniture dust in some epoxy and use that to glue the pearl. The black epoxy will fill in the gaps and be virtually indistinguishable from the ebony once everthing gets sanded flush. Under a finish everything will really shine. I'll post more pictures when I get around to the gluing, but that will be a while. I'm moving on to the fretboard now.

The End (Block)

You may remember that the braces for the back were radiused to a 15' radius and the top braces were radiused to 30'. Well, the sides now need to be radiused so that back and top will fit properly. To do so is simple: I just take the same radius dishes with 80 grit sandpaper and sand the sides while in the mold, first the back and then the top, until there are no gaps under the sides when they are on the dishes. It's not a lot of wood and 80 grit is pretty aggressive, so it doesn't take much time. Here's the back on the 15' radius dish:


I'm not quite done with radiusing, however, since the heel and neck blocks and kerfing will need to be radiused as well. I had to do the sides first, however, to get them down to their final dimensions. If I had waited until the kerfing was glued on and tried to do it all at once, it's possible that I would have sanded the kerfing so much that there would be a minimal gluing surface. This way I can glue the kerfing just proud of the surface and then radius it, leaving a good gluing surface.

Before gluing the kerfing I need to glue the end and heel blocks. This stabilizes the guitar shape in the mold. I have found that, unlike rosewood, the zebrawood likes to curl and twist a bit, and the heel and end blocks will bring the sides perpendicular to the top and back and keep them there.

Don't have a before picture to show you, but the end block starts as just a rectangular block of mahogany. I cut the width to 3" and the height so that it's just a shade over 4", which is the width of the sides at the butt end. The grain runs width-ways, parallel to the length of the sides, to give strenght in this direction.

Looking at an OM guitar straight-on at the top, you'll see that the bottom is not square but has a slight curve to it:
I have to match the curve on the end block so that it makes good contact throughout it's width with the sides. No gaps allowed! This is a critical joint, as it holds the sides together at the butt end and provides a good strong gluing surface for the top and back.

I bevel the inner surface to reduce weight. It may seem insignificant, but balance is an important part of a good-playing guitar. Plus it just looks better than a block of wood.

Here's the finished end block, held so you can see the bevel and the curve of the gluing surface:

After a dry run, I slather it up with glue:


And clamp that bad boy up, making sure the center line of the block is lined up with the center line at the butt end. I use a caul to protect the surface of the block:


You may wonder why I would bother with a caul, since once the back and top are glued on the end block will never be seen unless it's broken open, but that's the thing: maybe someday it will get broken or need repair, and someone will see it, and I want them to see that I took pride in my craftsmanship, not just in the parts everyone sees but also in the parts no one sees. So everything inside the box will get a good, thorough sanding.

Besides, I like Wayne Henderson's explanation for why he sands his end blocks: he says he wants all the notes to come out smooth and not get hung up on anything on their way out. Nice.

Once these two clamps are on tight I turn the mold sidewise and clamp it in my bench vise. This gives me access to the top and back ends of the block. Like I said, the zebrawood has a tendency to curl a bit, and where the sides extend beyond the mold they don't make good contact with the end block, so I use spring clamps to rectify this.

Here's the final mousetrap:


Seems that something as simple as making and gluing the end block shouldn't take much time, but all this took about 2 1/2 hours. Partly it's still my inexperience. I actually made two end blocks; the first one just didn't look good. If I hadn't had another end block I would have just fixed the first, but since I had another one I scrapped the first one, learned from it, and started over. The second one turned out nice, but the first one wasn't a complete waste; I used it as the gluing caul since it was the perfect size.

But inexperience aside, what seems simple and straightforward still takes time, and it's better to take the time because I'm more likely to avoid mistakes.

Now it's on to the heel block. This would normally just be a thicker version of the end block, but with the cutaway there's more carving to do.