Baritone Acoustic On Steroids

[Prostheta]

I think the wood is the least of your worries. The hardware will be the main cause of neck dive. I've seen truss rods made of carbon fibre, plus many manufacturers do their own versions of ultra light tuners now.

[Juntunen Guitars]

Got the sides bent today. I need to work on the spring placement on my bending mold a little.

I also got the soundhole cut out and the rosette glued in.

Stewmac circle cutting jig.

Glueing in the rosette.

I had to do a quick little mock up to see what it would look like.

I also got the X-braces for the top radiused and the upper X-brace is notched but I ran out of time to glue it in so that will get done on wednesday along with the rest of the top braces.

[Geoff St. Germaine]

The answer to how it looks is "amazing". Snakewood is gorgeous.

[Juntunen Guitars]

The answer to how it looks is "amazing". Snakewood is gorgeous.

Yes it is, I can't wait to get the fingerboard made. I plan to have it made either this coming week or the week after. It all depends on how much time I have to play with my CAD program and making tool paths.

I'll have more picture of this build coming up soon once I get them off my phone.

[Juntunen Guitars]

I've got a lot to update on here.

I had an issue with the x-brace, it didn't seat right so I had a nice gap on it. This day was starting to get me pretty mad because I was struggling with my archtop already so to top it off was this...

I shaved the bad x-brace off and made a new one. Here's glueing it in.

And the rest of the braces. I'm playing around with finger brace placement. The bass side finger braces I put at a sharper angle and a little closer to the upper x-brace to try and get a little more high end out of it. I tuned my 6 string down to what the tuning of this guitar will be and it was super bassy so I figure a tighter angle will bring out more high end, it works with x-braces so in theory this should work as well.

[Juntunen Guitars]

Here's making the blocks. I keep the grain going horizontally, the idea is so when the sides move with humidity changes it won't have to fight the blocks grain direction.

Since I'm doing a bolt on neck I decided I'd show you guys the neck joint I'm using. I originally drew one up as a mix of this one and the Taylor neck joint which is basically inlayed into the body but that would have taken more time than I want to spend on it so I figured I would just go with a normal mortise and tenon and then do a mock up of my joint later. The metal pins in the mortise are used as a punch to mark holes for where I drill the tenon mounting holes.

You want to leave a gap on all three sides of the tenon.

Routed slot in the actual head block. I used a forster bit to make positioning the bit easier.

Then I drilled the bolt holes.

[Juntunen Guitars]

Shaping the back braces. I use two finger planes and a ruler with self adhesive sandpaper on it.

When I got the rough shape done I started to voice it. I have no idea what to look for with a back compared to a top so I just started shaving away areas and scalloping different spots to see how it would affect the tone. I finished when it still had some stiffness to it but I was also able to get either a nice rumbly tone or bright crisp "ping" sound everytime I'd tap it while holding it in different places. This is all part of me experimenting to see how back braces affect the tone. By the way, violin knives make great tools for scalloping smaller areas.

[Juntunen Guitars]

I got the back glue joint strips glued in as well. This was a pain, I had about two hours into cutting these out and shaping them with a chisel then hand sanding them to be scratch free. They are just cut off of the cedar top so they also liked to break off their tips so a lot of time was spent super glueing things back together.

I also got the kerfing in.

[Pestvic]

damn man this is just awesome!

[Juntunen Guitars]

Finding out string gauges and settle in. So with a flat top guitar you need to figure out the expected settle in that the guitar will adjust to as the wood is first getting compressed and moved by the string tension, to figure that out you need to know string tension. In standard tuning with the strings I use on my 6 string (D'addario .013's) there is about 180 pounds roughly put on the top. I ofen to to an open tuning so I'm guessing it's more around 150-160 with the tuning I use but I haven't figured it out exactly. With the 8 string having an extra low and high string and being tuned from a low F# to a normal standard high e I want the string tension to be about 180-165/170ish to try and reduce a ton of pull on the cedar top but still have good tension and since it's a fan fret guitar there is technically 8 scale lengths.

The equation for string tension is T=(UW(2SF)²)/386.4 where UW is unit weight (found on the D'addario string chart, S is the scale length and F is the notes frequency in hz. The string guages end up being about .012-.080 and about 175 pounds on the top.

I think I'm going to leave it this way for now and see how it feels but it should be about right. Here's how my math was done.

The downside to this is I will never be able to tune up to standard without destroying the guitar. When tuned to standard it would be about 311 pounds, if the guitar were to survive it my fingers wouldn't

[Juntunen Guitars]

damn man this is just awesome!

Thanks man, I'm enjoying this build a lot.

[Juntunen Guitars]

Notching the kerfing for side braces to help prevent cracks.

[Juntunen Guitars]

I had a lot of issues with the cedar center seams. Normally I'd just glue in the strip then cut out slots to fit in the back braces but with a 3 piece back and double x-brace I figured it would work better to fit each piece individually well I had a lot of corners fall off because cedar is so soft so here's fixing them. I fit new corner pieces in and then once the superglue dried I used an xacto knife to cut off the excess and sanded the bevel in to match it. It ended up working pretty well.

I also opened up the neck pocket.

[Juntunen Guitars]

Here's a shot of the sides before they were notched to fit the back braces.

Notching the back brace slots.

Glueing the back on. I had to take it to a radius dish first though to radius the block ends and the radius the edge of the sides to match the tops radius.

[Juntunen Guitars]

Back on.

And of course I forgot to add the x-brace caps so back to the go bar deck.

[Juntunen Guitars]

Finishing up the top braces here. I left the bridge plate slightly thicker than a 6 string just because of the extra wear it will get from the 2 extra strings, also the hope is that it will help keep the top from getting a bulge behind the bridge like a 12 string does.

Working on the top braces. Originally I expected the strings to put out a lot more pressure so I made the braces pretty beefy in every dimension but in the end it ended up stiffening the top way to much so I spent a lot of time shaving off a lot of brace wood just to loosen it up before I could even voice it.

[Pestvic]

Man that's looking so damn good!

[Juntunen Guitars]

Here's my process for doing side purfling. I thickness the binding down a little oversized, tape the ends of the binding and the purfling together then wrap it with sewing thread to keep everything tight. Then I use Stewmacs thin super glue that is the viscosity of water to seep inbetween the two woods, after an hour of drying I use a razor blade to scrape off the glue and the thread and I thickness everything to final thickness.

An issue you can run into with superglue and figured wood is the glue seeping into the figure and "freezing" it, much like when you put a stain on flamed maple to accent the flame but when you use glue it can cause the figure to not change appearance when you shine the light on it so to try and keep that from happening I keep everything thick and then try my best to sand off as much glue that seeped in as possible. Sometimes it works but sometimes it doesn't.

[Juntunen Guitars]

It seems a lot of acoustic builders do this part differently. Some use a radius dish the same way I do for the back and radius the whole top edge, others use a radius bar and just sand a bevel into the edge. I do this because my sides have a flat edge on the tops glueing surface but a curved edge on the back, If I were to sand the top on a radius dish it would curve the top edge and it would throw off measurments. Kind of hard to explain but if you look at the picture of my side template you will see the flat and curved edges I am talking about.

Top edge beveled with a 20' radius and then 25' radius at the top edge where the neck goes. I put a little bit of a flatter radius on the upper transverse brace just to make sanding the neck extension height easier so I don't take away toom uch wood.

Glueing on the top.

Starting to look like a guitar now. Next week I'll be working on the neck more, binding the body and maybe getting the fingerboard made.

For a 17" lower bout it's surprisingly comfortable to sit with. I was getting a feel for it and it wasn't much different than the dreadnought I built last spring except my arm was a little high up but oh well, it's a lot better than I thought it would be when I originally drew the design.

This design was the result of me drawing a dreadnought shape then basically morphing it into a bigger shape. I think when happened was it was lengthened by an inch or so then the lower bout was widened, the waist stayed the same but was moved up a bit and the upper bout was more rounded if I remember right. The idea was to get a medium jumbo sized guitar that was still comfortable to play.

[Juntunen Guitars]

Time to update, this last month had been busy with class and everything going on.

I decided to do some inlays. I wasn't sure if I wanted too or not with a snakewood board but I figured since I already have an expensive board and need to sit back and watch a machine cut the fan fret sots hoping I didn't forget something in the CAM program and have a very expensive piece of firewood I might as well cut some more hopes in it right?

Here's the print off.

The woods I am using is Bocote, Padauk, Maple and Mahogany. The leaf stems are made out of Walnut.

[Juntunen Guitars]

[Juntunen Guitars]

Setting up for routing the binding channels. The jig I used is made off two drawer sliders that let the router slide up and down, I think it's the one LMI sells. I don't like the idea of using a dremel because the bit can flex some and the channels won't be squared to the side, they will be squared to the top radius.

Here's the craddle the guitar sits it to keep it square.

Setting up to bend the binding. I was a little worried about the snakewood because it's supposed to be brittle but I had no problems bending it. It bent just as easy as any other wood. I use the same method to bend the binding as I do the sides.

[Juntunen Guitars]

I completely forgot about the end graft area and got a nice little bump in the binding channels so I had to patch that. I'm glad I hadn't gotten rid of my left over cedar yet. I fit it by just sanding it and checking its fit. I couldn't clamp it so when I glued it I had to hold it and push it in place for about 10-15 mins or so until the glue had set up enough to hold. After the glue dried I used a chisel to clean up the slots and get everything set again.

[Juntunen Guitars]

Glueing in the end graft and binding. I forgot to take pictures of cutting the end graft slot but I just do that with a japanese saw and chisels.

[Juntunen Guitars]

Long time no update. I'v been busy with classes, building 3 guitars and getting ready to move again in may so it's time to start crunching down on some projects. So here's where it's at currently.

Getting set up to cut the fingerboard on the CNC. I almost messed this up in a way. When I drew the fan fret in my CAD program I just made a 4" wide rectangle and then lined up the two scale lengths and connected the dots, well the problem with that is that only works if I had a 4" wide fingerboard that had no taper or anything in it so when I was measuring everything while setting up the tool path I noticed they were off so I had to draw them again by matching the scale length to the taper of the board. That time it worked out fine. In reality I could have just altered my bridge location and it would have worked but the high e strings bridge pin hole is so close to the x-brace as it is that I was afraid I would drill into the brace if I had to move it up. I ended up having to redesign the bridge placement anyways and make it a 15 fret to the body instead of 16 to make it work since I changed the x-brace angle from 98 degrees like Martin does to a 96 degree angle when I glued the braces to try and make more highs come out since this will be tuned lower than normal I'm hoping that the higher end angle will make notes not so muddy with the low F# and cedar top. It works in theory but we all know how that goes.

The jig for the fingerboard is a vaccum press with plexi glass on teh sides to hold it straight. The problem I was running into was the FB is so wide at the last few frets that the snakewood wasn't actually wide enough so I had to add binding to gain the right thickness I needed which also gave me absolutelly no room for eror in setting this up unless I wanted a nice little gap at the end. I also had to change it from a 24 fret neck to 23 but mainly because there would have been too much hanging over the sound hole with the bridge relocation.

The fret slots were cut with a .022" spiral cutter. First time I saw that bit I laughed a bit, I'd never seen a cutter that small and I thought it was a joke.

Mitering the binding. Some people don't realize how easy this is. Sharpen your chisel until it's really shiny on the back and then you can use the reflection of the board to match the angle. I'm not sure how to explain it so hopefully the pictures make it self explanitory.

I also got the truss rod in. I don't understand stewmacs hot rod truss rods. You buy a special bit that fits the brass ends of the rod but the adjustment nut is wider. Usually I just chisel out the extra space but I had a 1/4" bit sitting on the side of the router table to I popped that in to see what it did and just like that I figured out how to make the adjustment nut fit perfect.