Building an Acoustic Guitar From Scratch (Dreadnought)
by superpengy10 in Workshop > Woodworking
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Building an Acoustic Guitar From Scratch (Dreadnought)
How to build a dreadnought (1937 Martin) recreation guitar. An incredibly fun and rewarding project. It took me 37 days to complete this guitar not including planning, finishing, drying time. Pictures are primarily from my pau ferro guitar but a few are from the internet and a friend's guitar. I hope you enjoy reading!
At the time of writing I am 18 years old and about to start class at the University of Maryland majoring in mechanical engineering.
Supplies
This is the wood I used. We will talk about wood selection in the next step.
Materials:
Wood - Sitka Spruce - Soundboard (top), Braces
Wood - Pau Ferro - Back Plate & Sides
Wood - African Mahogany (Sapele) - Neck Body, Kerf Lining, Neck Block, & Tail Block
Wood - Indian Rosewood - Fretboard, Rosette Inlay, Bridge, Neck Head Plate Veneer, Tuner Knobs
Wood - Wenge - Bindings, End Wedge, Heel Cap
Wood - Ebony - Bridge, Sawdust filler for repairs
Wood - Bass Wood - Mold Spreaders
Wood - ¾” MDF Board - Side Molds, Steam Box, Side Bending Mold, Radius Dishes
Metal - Stewmac "Gold" - Fret Wire
Metal - Brass - Tuner Pegs
Bone - Unbleached - Nut & Saddle
Pore Filler - AquaCoat water based wood grain filler - Pore Filling On All Exposed Parts
Finish Compound - Behlen (Mohawk) Vinyl Sealer - Sanding Sealer Coats on Body & Neck
Finish Compound - Behlen (Mohawk) Instrument Lacquer - Sprayed Finish on Guitar Body & Neck
Oil Finish Compound - Odie’s Oil - Fretboard Finishing & Tuner Knob Finishing
Adhesive -Titebond Type 3 Wood Glue - Back & Front Glue ups, Bracing, Neck Construction, All inlays/binding.
Adhesive - Titebond Type 1 Wood Glue - Neck to body
Adhesive - Thick and medium superglue - various applications
Guitar specific tools:
Heated Blanket (or steam bender) - Bending Sides & Binding
Binding Tape - Clamping Binding & Purling
Bridge Clamp - Clamping Bridge During Glue Up
Plans - Gen One Luthier's Etsy Store
Wood Selection
Let's start with the fun part! What wood to pick. I would highly suggest checking if there is a hardwood lumberyard near you that has a large luthier section. My "local" hardwood store is Hearnes Hardwood which has a very large luthier section. I was able to look through hundreds of sets of different types of wood to find the one which I liked the most and was a good price. If not Ebay (if the seller has a good rating) and Stewmac are great places to get wood.
Back and sides - Before selecting any wood there are two things to look out for. The hardness of the wood and it's ability to bend. Harder wood will create a deeper tone but you need to ensure you are able to actually bend the wood you buy. For hardness I would check out https://www.wood-database.com/pau-ferro/. We use the Janke scale to measure hardness. For bendability Stewmac has a variety of fabulous resources. Many guitars use some very exotic woods that are not used to often so read a bit to make sure the wood is reasonably workable. I ended up using pau ferro because of its ability to easily bend and I liked how it looked. My sides are 0.110 inches final thickness. You can buy your back and sides at this thickness or do it yourself with a wide belt sander or drum sander. I did it myself.
Soundboard - By far the most popular options are either Sitka or Engelman spruce. They have slightly different tonal properties with Engelman being softer than Sitka, making it have a more lush sound with more overtones. Sitka has a good dynamic range and is very responsive. I went with Sitka because my friend used Engelman and wanted to see the different sound. My soundboard had a final thickness of 0.093 inches. Before you work with your spruce (especially at final thickness) be very careful. Spruce stains very easily.
Bracing - Sitka or Engelman spruce work very well. You can use a mix of them placing the Sitka in places where the guitar might need more strength like the sound hole and Engelman on the rest. The lower density will allow sound to reverberate slightly longer. Your bracing needs to be quarter sawn.
Kerfing - Most use mahogany, spruce, or basswood. Mine are mahogany because I wanted to match it with my neck and heel blocks. I used a set from Ebay which can be found here.
Neck - The two most popular options are mahogany and maple. The neck does effect the tone of the guitar so pick something that matches your body. Mine is Mahogany. The important part is your neck needs to be made of straight grain quarter sawn material. This will give it much more strength.
Bridge - Most are either ebony or Indian rosewood. Mine is ebony and I bought it pre-shaped on Ebay. I did not have the confidence I would be able to shape it myself with enough accuracy. It does need to be a Martin bridge.
Fretboard - There are a huge number of fretboard options but one thing of note is that the fret slots need to be incredibly accurate. I would buy a rough cut one from stewmac. It is not very easy to do it yourself without a CNC and special fret cutting tools.
Binding the purfling - Purfling is optional but binding is required. You can make your own solid binding or buy multicolored binding from stewmac.
The other woods on the guitar don't effect tone very much and really any type can be used.
Making Jigs
There are four specialty jigs you need to complete this project. An internal jig to bend the sides, external jig to hold the sides in place while you add many components, a go-bar deck, and at least one radius dish.
The internal and external jigs should be made made of MDF. The first step of this project was to focus on the sides. In order to do this, I needed to create the molds to build the guitar around. I utilized ¾” MDF boards that were eventually laminated to make these molds. For the negatives, I drew the plans for the molds & cut a single template of half of the full mold on the bandsaw. Once it was cut & sanded on a disk sander, I rough cut the other five identical parts on the bandsaw. Using the original template as a guide, I flush cut each part on the router, making all six pieces completely identical. These six pieces were glued in two groups of three in order to create both halves of the mold. To prepare for the glue up, I drilled three holes in each piece for a ¼” dowel to ensure that the pieces did not shift during the glue-up process. Using Titebond type 3 wood glue to ensure a durable bond, the six pieces were laminated in two groups to make each of the two halves of the final mold. The mold was made in two halves, rather than one full piece, in order to allow for easy removal of the mold from the sides in later processes. I later made three spreaders, using 8/4” basswood, carved to resemble the positives of the upper bout, waist, & lower bout of the guitar on both sides, & connected them using turnbuckles that allowed for adjustment in clamping pressure of each spreader.
The positives of these cut mold parts were then used to create a single bending jig. They were spaced out using shallower versions of each to allow for airflow for the heat bending process. ¾” Holes were drilled on the drill press, with 3” of spacing between each around the perimeter of both sides of the mold for spaces to utilize F clamps for the later bending process. To compliment this, using 8/4” basswood, I carved small negatives of the 4 points with the most extreme curve to use as clamping blocks.
Your go bar deck could be like mine which is just a cart I flipped and put on the table. My bars are made out of poplar. Ensure the bars are all uniform thickness (you will thank yourself later) and the correct uniform length. If they push to hard you will dent your spruce.
I made my radius dish on a CNC which is the only point in this project which I used one. Mine has a 25' radius which is pretty standard and is made of MDF. Many guitars use a different radius on the from comparted to the back. You can also buy a radius dish. Using spray glue I covered it in low grit sandpaper.
Bending Sides: the Two Methods
There are two ways to bend your sides both of which I have done. You can either bend your sides with a heated blanket or use a steam box. Here are the pros and cons of each.
Heated Blanket
Pro
- Much longer working time (15 minutes ish)
- Ready pretty much immediately
- Don't need to make steam box
- Holds shape better
- Minimal warping on ends
Cons
- It is hot
- Easy to burn wood
- Can't touch it because it will burn you.
- Harder to tell if you are bending your binding straight
Steam Box
Pros
- No heat
- Easy to ensure wood is not cracking
Cons
- Short working time (3 minutes tops)
- Waiting 20 minutes for the board to be ready to work with
- Making a steam box and buying a steam generator
- Holds shape worse
- Might just be me but my one side got a very thin crack about an inch long in it. I believe this to be because it is a tropical hardwood.
- Made the ends of both of my sides wavy
This being said I think the steam box works incredibly well for bending binding. Being able to see the binding while you bend it to know if it is straight is really useful. For the sides I prefer to heat bend it. I like the longer working time and the ends of my sides not being wavy.
Actually Bending
I highly suggest you buy your plans here and have them printed on a poster printer at full scale. This gives you the ability to cut out the paper and spray glue it to a piece of wood making it easy to cut the sides out. You can also measure right on the page. Before you bend your sides cut out the side template and cut 1/2 from the line on the long sides and at least 2 inches on the short sides.
Heated Blanket Bending
- Run wood under cold water on both sides. Leave for 5 minutes and do it again. Ensure the wood is no longer soaking in a significant amount of water before you start.
- Encase wood in contractor paper towels.
- Encase wood in tin foil.
- (optional) place thin stainless steel on top. Makes the wood heat up slower the spreads the heat more uniformly.
- Place heated banket on the top. Use spring clamps on the edges to clamp the wood to the heated blanket. Remove any rubber covers on the clamps they will burn.
- Heat up blanket to 280F for softer woods up to 320F for harder rosewoods. You can poke a hole in the tinfoil and make sure steam is coming out.
- Ensure the side is in the jig so when bent it is straight and is long enough to overhang on both sides.
- Start with the clamp in the middle creating the concave area toward the center of the guitar. Don't clamp this all the way down.
- Place a block of wood to the top of the convex area and slowly pull down toward the outside. Do the same for the other side.
- Fully tighten the clamp in the center.
- Allow the assembly to naturally cool down then heat back up to temperature and cool down again. This rebuilds and destroys the lignum in the wood making the wood want to keep its shape.
Steam bending
- Turn on steamer and leave it allowing it to build up steam. The rule is per inch of thickness it takes a full hour to steam. While the guitar sides being thin they need a little bit of time to gain moisture. 20 minutes works well and I believe my side gained its small crack from being left in for way to long (40 minutes)
- Ensure the side is in the jig so when bent it is straight and is long enough to overhang on both sides.
- Start with the clamp in the middle creating the concave area toward the center of the guitar. Don't clamp this all the way down.
- Place a block of wood to the top of the convex area and slowly pull down toward the outside. Do the same for the other side.
- Fully tighten the clamp in the center.
- Leave clamped up for two days. Can be transferred to outside jig if done quickly.
Heel and Neck Blocks
The top and bottom of the sides have two blocks glues connecting them. Before you glue the sides together trim off the excess length with a Japanese rip saw. The sides don't need to be perfect in length but they should be close. Follow the plans and make the blocks out of hardwood. If you need to glue multiple pieces of wood together you can. If you plan to add a pickup jack or something you might want to make the heel block out of plywood to help prevent cracking. I made both of my blocks out of mahogany. Make both blocks a tiny bit oversized in length. Glue them on centered at the top and bottom of the guitar accordingly. When you radius your sides you will sand these to be perfect length. After you have your sides connected together use a finger plane to make your sides the correct width. You can add chalk to the sides and see where material is coming off when sanding on the radius dish. To sand on the radius dish twist your sides on it while they are in the external jig. Make sure you don't go under the correct width. The sides don't need to be perfect and it will be much easier to sand once the kerfing is added but the correct width needs to be within the correct ballpark before it is added.
Kerfing and Side Braces
Kerfing gives your guitar the required amount of surface area. Buy your kerfing on Ebay or from Stewmac. Kerfing simply is a piece of wood with a bunch of tiny grooves in it making it flexible. Glue your kerfing on a bit proud of the sides and use cloths pins to clamp them. You might need to use more than one piece of kerfing. I used mahogany kerfing. The kerfing goes on all 4 edges of the sides.
Side braces add a bit of strength to the guitar along with preventing any crack that might form from going all the way around the guitar. My side braces are made of mahogany and are 5mm wide. I shaped these to a point on the disk sander to make them more stylish. Glue these in according to the plans. I measured from the center point of the guitar to the outside edge using the length I measured from the plans. This gave me the location of where to glue these in.
Radius Your Sides and Mortise
To start with, what does it mean to radius your sides? If you imagine a ball that has a certain radius its curvature would match that of the top of the guitar. This gives the guitar a greater amount of strength along with having tonal benefits.
Since your sides should already be close you can move on making this radius on your sides. While the side assembly remains in the outside jig begin twisting it on the radius dish to create the curvature on the kerfing. Use chalk to track your progress including on the blocks. The sanding should mostly be done applying uniform pressure. Non-uniform pressure can make the width between sides vary causing a problem. Do the same for the other side. It is tedious but needs to be done.
Next you should cut the mortise for your neck. Follow the drawings for the size of the mortise. I used a band saw to cut out the majority of the material and a chisel to finish it off. I then drilled two holes in the mortise. We will use these to bolt on the neck later. The bolts allow the neck to be test fit with ease along with applying clamping pressure when the neck is attached.
Install End Wedge
First you need to cut your end wedge. Cut out a wedge on the bandsaw trying to keep your cut as straight as possible. Next take your wedge to the disk sander and make both sides flat. Mark a center line on your end wedge. Using double sided tape, attach your end wedge to the end of your guitar lining up the center line in the wedge with the center of the heel block at both the top and bottom. Using a very sharp cross cut Japanese saw use your end wedge as a fence and cut through the sides if your guitar. Once you do this on both sides use your pole saw to make multiple cuts throughout the area where your end wedge will go. Using a chisel to pop out the small pieces. After using a file you should be able to slot the end wedge in with a tight fit. You can also add thin pieces on the outside of the wedge to make it more fancy. I added pieces of my purfling to the wedge so I could miter it into the bottom of my binding. Add a bit of glue and slide the wedge in. Place a caul and camp on the top. Trim the wedge.
Prepare and Glue the Two Pieces Back and Soundboard Together
Decide which way you want to book match your pieces. After that you need to make the edges you plan on mating perfectly flat. My jointer happens to be set up very well so I all needed to do was run my pieces over the jointer very slowly taking a very light pass 3 times to make both sides perfectly flat. I ran both pieces over at the same time with the pieces stacked so that the faces on the outside of the guitar are not touching each other. This removes any error potentially created by the angle on the jointer being slight off. Hold the two pieces together up with a light behind it. If any light comes through the joint needs more work. If your jointer is not set up as well you can make a shooting board using either a plane or a level covered in sandpaper to make the joint. There are many ways to glue your sides together. I glued mine together lying on the piece of melamine using long cauls. To hold the boards flat I places cauls on the seem with cinder blocks on them. This joint needs to be good. After this I ran my back and soundboard through the wide belt sander to bring them to thickness. My back is 0.110 inches thick and my soundboard is 0.093 inches thick. If you want to trim these pieces you can trace the shape on leaving about 1/2 on each side. You can also do this step later.
Rosette
For this step you can either use a trim router or a Dremel. You will also use this tool to do your binding and purfling. I have only ever done this with a trim router so that is what I will be talking about. To start you can make the rosette yourself or simply buy it. Whatever you pick you also need to buy a bit that is the same diameter as the width of the rosette. I made a simple circle jig for my trim router but you could buy it. My jig simply was a piece of wood with a hole for the bit and mounting holes to the trim router. I then drilled a hole in the jig the radius of the rosette away from the center of the collet. Using a dowl with a tight fit and simply spun the trim router on that point. Set the height carefully to ensure you don't go through your top. The rosette just needs to be barely set into the top. Do many tests on scraps to ensure the rosette fits perfectly. When you cut the channel in your actual top since it is thin add a scrap of wood behind it with the pivot hole for stability. Add a small amount of glue to the rosette and place a weight on top. Once dry sand until flat.
Making Bracing
Start by checking your spruce. Your bracing needs to be quarter sawn and should either be Sitka or Engelman spruce. Looking at the drawings roughly cut your spruce to shape. I cut out the templates from my plans and spray glued the to my bracing to make cutting the shape easier. Next hold your bracing up to your radius dish. Using a carpenters pencil (or a normal pencil with one side grinded down) hold your bracing up to the radius dish and draw a line on your spruce. This line will match the curvature of the radius dish. Using the disk sander sand close to your line. After this finish sanding using the radius dish. Use chalk to track your progress. Hold near the outside or you will simply flex the brace when sanding. Repeat this process for all the braces on the front and the back. If your braces are radiused incorrectly there will be unnecessary stress in the plate and it will be flat. Leave the braces a bit long so they can slot into your kerfing. Shape the profile of the braces as much as you can before you put them on. We will finish shaping them once they are attached.
For the back strip I suggest doing it in multiple pieces. The grain should run perpendicular to the seam in the back so it acts as a stitch. If it is one piece you will need to cut slots in it for the braces.
For the soundboard I suggest printing a to scale picture of the bracing pattern then glue it to a thin piece of MDF. Drill small holes where the braces intersect big enough for the tip of a pencil to fit through. Place the template on the back of the soundboard and use a pencil to mark all the points of intersection. Draw lines connecting these points so you know where to place the braces.
Glue on Braces
For this step you will need to use the go-bar deck. Place your radius dish at the bottom of your go-bar deck and place the piece you plan to add braces to on it. Add glue to the bottom of the brace after marking where you want to line it up. Using the go bar deck add multiple bars to the brace. There should be no gap between the brace and the now bent piece of wood. Continue this process until all the pieces are glued on. Do no overuse the glue. Add the back strip last if it is multiple pieces cutting the length of each section based on the distance between braces on the back. Add the back strip first if it is one piece. You will need to cut into it to add the braces.
Shaping Braces
The goal here is to make the braces thin so sound resonates well but not so thin that the guitar becomes weak and breaks. You can voice your guitar but I don't know how to do that so this is my simplified method. My first step was using a chisel to remove the bulk of the remaining material aiming to make my braces pointy like the drawings. I then used a finger place to make each side of the point flat. The final step is to taper the ends to the braces to nothing. Using the chisel upside down will help you make this smooth. They need to be thin on the end so we can tie them into the kerfing.
Place the back of your guitar on the table. Align it with the sides. Using a marking knife mark where the braces intersect with the sides. Using your pole saw cut on the edges of these marks. Make a few more cuts and use a chisel to pop out the small pieces. Repeat this process until all braces are sunk in the sides. The braces near the sound hole should be done first as these will be the ones easily visable
Glue on Your Back and Soundboard
It is important during this step to get constant pressure on the entire outside of the guitar. I used a system of clamps on the outside of my external jig used to hold the sides to clamp my top and bottom on. The clamps are simply a piece of all-thread which I cut up and added small pieces of wood with threaded inserts to the end. You probably don't need as many as I used but more can't hurt. If you don't want to make this setup you could use your go bar deck with either shorter bars or a taller stand.
Next you should trim the remaining amount from your back and soundboard. To remove the bulk cut it on the band saw. Set the angle of the table off of 90 to prevent accidental cutting into the sides. Remove the rest with a flush trim bit. Next you need to flatten your sides. From bending they might be a tiny bit wavy. Using a straight tube covered in sandpaper flatten your sides. You should be able to check for flatness by using something like the edge of a ruler. If there is no gap the sides are flat. The sides need to be flat because the bit for the binding channel indexes off the sides.
Cutting Binding and Purfling Channels
Start by bending your binding. Follow the same procedure you used to bend your sides. Really focus on trying to keep the binding straight during the bending process. If you have a really oily wood with a really light wood it may stain it from the steam. This should go away once sanded.
I completed this step using a trim router. If you plan to use a Dremel I would only recommend using the Stewmac jig and bit. For the trim router you need to buy the Stewmac bit. It is expensive but is totally worth it. I spent 4 hours switching bearing and grinding the slightest bit off the end of bits before I finally gave up and ordered the Stewmac one. It includes bearing that are very close in size allowing you to make the fit perfect with your binding.
There are many ways to create the stand to do the binding. The trim router needs to be held at a perfect 90 degrees at all time and the top of the guitar is not flat. This is from the radius of the sides and the side profile of the guitar is not parallel. Using a large piece of aluminum angle I drilled holes to fit my trim router. For the center hole I mounted a Delrin bushing to ride on the top of the guitar. I placed this assembly on a linear bushing using the 8020 system. The guitar was then mounted to a stand allowing me to adjust the height of the top of the guitar from 4 points. Before I made my binding I adjusted the feet so the top of the guitar is flat. Here is the link to the Stewmac stand.
On a test piece using the jig create a groove. Using your binding test the fit. The edge of the binding should be a tiny bit proud on all sides. Adjust until it is perfect. Next to the same with the purfling. It should sit proud toward the top of the guitar but fit perfectly in the binding channel. Once you have ensured both are perfect on a test piece do it on the actual guitar. If you simply go around the guitar you will get an extreme amount of tear out. Look at the picture above. Any place that does not have an arrow move the router in a opposite direction f the arrows very slowly. This will mitigate tear out.
Glue in the Binding and Purfling
To complete this step you will need Stewmac's binding tape. Normal tape will tear out the wood fibers on the top and there is no other real way to clamp this. Starting at the bottom add glue to the channel and begin taping on the binding the purfling. You can glue them in together or separately. Don't add glue on the entire channel at once. The glue will begin to set at the end before you get to it. To use the binding tape place it on the side and pull it tight as you wrap it around the top. This will create enough clamping force to hold the binding on. Go around the guitar until you complete the entire thing. Remember at the top it will be covered by the neck. Focus on making the joint perfect at the bottom near the end wedge. Once you do this you are done with the guitar body.
Neck Blank and Tenon
We are now ready to move onto the neck! The piece of wood you use for the neck needs to be quarter sawn and straight grained. This will give it a significant amount more strength compared to a normal piece of wood. Following the plans cut four pieces of wood to make the part of the neck where it connects to the guitar. Don't forget to leave enough length for the tenon. Glue these pieces to the guitar attempting to keep the grain looking natural. At the top of the guitar we are going to cut a 15 degree scarf joint. First, mark where the joint needs to be cut based on the plans. After than go to the band saw and cut on your mark as straight as you can. I used a resaw band saw to perform this cut as the wide blade helped me to make it straight. After that flip the piece you cut off over the glue it back on top. This can be a difficult glue up because the neck tends to want to move. Follow the picture above to prevent this. After the glue has dried used a combination of the disk sander and a hand plain to make this section flat.
The next step it to create the tenon on your neck blank. The end of your neck needs to be the angle of your soundboard to the sides. Once you know this angle use the miter saw to cut this angle on to the end of your neck. I then marked the size of my mortise in the center of the neck. I used the router to cut tenon. Holding the neck upright I set the fence so the router would take away the material. I did this over the course of three passes. Slowly running the neck over he router removes the material without the neck jumping. Be careful to keep the bottom of the neck planted on the table. This will create the angle on the neck that contacts with the body of the guitar. Once you complete this process you are ready to add the threaded inserts into the neck. Push the neck onto the guitar and mark the holes. Drill a hole for the threaded insert in the tenon. Make sure it is the correct size or when the threaded insert is added it will crack the wood. Add a small amount of medium viscosity super glue when adding the threaded insert to prevent it from coming out.
Truss Rod and Fretboard Mounting
First we will create the truss rod mounting slot. This is completed on the router. Measure the width of the truss rod and select a bit of that diameter. Hold the truss rod up to the side of your neck. Mark on the side of the neck where you need to stop making the channel. If you make the channel to long the truss rod will not work. Next mark the center of the neck. You should use a router table with a fence to complete this operation. Place the neck face down on the table lining up the center of the neck with the center of the bit. Push the fence up to the neck and lock it in position. After this simply set the bit to the correct height and make the cut. Glue in the truss rod using super glue or epoxy.
The fretboard will act as a guide as you carve the neck so it should be glued on now. I started by spray gluing on the fretboard template from my plants to get eh shape correct. I then cut the fretboard about an 1/8 of an inch oversized side to side and on the mark at the top. Mark the center of the fretboard on the ends and the center of the neck. Make sure to leave space for the nut at the top. Glue on the fretboard using a caul. Once this joint is dry cut the excess off the neck not forgetting to leave space for the headstock.
Headstock
To shape your headstock it will be easiest to make a template the flush trim it using the router. Cut out the headstock shape spray glue it to a piece of MDF. Align with the fretboard and use double sided tape to attach the template. Don't forget to leave space for the nut. Using the band saw cut close to the template. Since the neck is curved use a flush trim bit with the bearing at the bottom to finish cutting out the template.
The headstock of the guitar is a spot for the luthier to add personal touch to the guitar. My headstock is a piece of wenge with thin pieces of cocobolo going through it. I started by using the wide belt sander to create a thin sheet of cocobolo and cut into 1/2 inch wide strips. It only needs to be thin enough to be flexible one cut into strips. I then ran a piece of wenge large than my headstock through the planer until it was about 1/4 of an inch thick. Using the band saw I made one curved cut. The trick to getting this to work is to do a smooth cut with a large radius. I then used super glue to reattach the two pieces with a piece of bent cocobolo in the middle. I repeated this process until I thought the headstock looked good. After cutting off the excess on the band saw I ran the headplate through the wide belt sander. I then glued the headplate with a maple veneer underneath on the headstock. Using a flush cut bit and the already cut out neck as my profile I fit my headstock.
Shaping the Neck
To start shaping your neck create a heel cap. This will guide you as you shape your neck. It can really be any shape so long as it is big enough that the threaded inserts fit inside of the neck. Once you glue this on it is time to shape the neck. I bought to Shinto rasp and it worked really well. I was able to shape the entire neck in two afternoons and it was quick. You should get out every rasp and file you have there are some awkward angles throughout this process. Run the rasp on the course side over the neck. The more you angle the rasp the more material it will remove. Once your get close to final size or want to get a feel for the neck flip the rasp to the smooth side and it will quickly make the neck smooth enough to move onto low grit sand paper.
There are many different designs you can use throughout the neck. I did a relatively simple design with a small bump where my tailstock started and a point by the heel of the guitar. Follow the plans for the thickness of the shaft. This will ensure it is strong enough to feels good in your hand. There are a few neck profiles to pick from. Mine is a C shape because that is what feels best in my hands.
The final step before finish is to fit the neck to the body. Using the thin chisel take away material next to the mortise leaving around 1/4 to the outside of the neck. This will prevent any high spots toward the middle the neck during the next step. Put the neck of the guitar on the body with a piece of 120 grit sandpaper between them. pull out the sand paper to the side. Pulling it out the back can change the neck angle. Repeat this process until the neck fits on the guitar.
Sanding Finish
Before beginning the sanding and finishing process blue tape needs to be placed on the bridge area, fretboard, mortise, tenon, and the area where the fretboard overlaps the guitar body. I did not add a cover over my sound hole figuring finish would go in making the guitar look better on the inside. Sand the entire guitar up to 320 grit. Ensure that there are no weird bumper or errors. There is no going back from this point. Once you are sure there are no errors you can start adding grain filler. I used aqua coat grain filler. I added three coats of grain filler. On closed pore wood (such as pau ferro) the grain filler will fill the pores easily. On open pore wood (such as Indian rosewood and wenge) it is very important to really push the grain filler into the wood. Wipe of the excess after 15 minutes and sand to just leave the remaining grain filler in the pore waiting at least 45 minutes between coats. I then added three coats of sanding sealer. Simply spray it on like spray paint scuff sanding between coats..
I am fairly new to finishing wood with lacquer. I used Mohawk instrument lacquer in my spray gun. I added roughly 10% lacquer thinner and adjusted my mixture. Remember that lacquer is only about 20% solid so most of what you spray on is going to evaporate off. I did ten coats of lacquer sanding between every other coat. I started at 400 grit and went up to 1500 grit. I waited at least 5 hours between coats but I believe you can add another coat in as little time as an hour after the previous. Before finish sanding the guitar needs to sit for at least 10 days in a low moisture environment while parts of the lacquer evaporate.
After ten days I started wet sanding the guitar starting at 1200 grit going all the way up to 5000 grit. I decided not to buff the guitar because I liked the satin look but this could be done later.
Frets, Side Markers, and Tuners
Before installing the frets sand the fretboard up to 800 grit. Be very careful to not sand the radius out of the fretboard. Since my fretboard was already fairly smooth I simply hand sanded to 800 grit and did not lose my radius. If your fretboard is going to require a lot of sanding using a thin and long steel beam will allow you to sand the fretboard without losing the radius. The frets are hammered into the fretboard using a fret hammer (or at least a hammer with soft ends that will not dent the frets or the wood). I used a special fret hammer with brass end which can be would here. I don't think this is required to do the frets but certainly makes it easier compared to a normal hammer. I cut a section of fret a bit longer than required. I then placed a drop of medium viscosity super glue on both end and the middle of the slot. After I hit one side of the fret and then the other followed by repeated hits throughout the middle of the fret. The super glue helps the fret stay seated in the slot on the ends.
Using a flush cutter I cut the excess material on the frets as close as I could to the neck. Using one long file and a bunch of small ones I filed the ends of the frets down so they were flush with the side of the neck I then filed a small 45 degree angle on the end on the frets. Place blue tape on the sides of the neck to prevent accidental scratching from filing.
I decided fairly early on in the project that I did not want dots on the front side of the fretboard meaning I would need to use side dots. I started by using calipers to mark the location of the side dots. I then used an automatic center punch at that point to ensure the drill bit would not wander causing the dot to be off. At a slow speed to used a hand drill to make a shallow hole that fit my end marks. The end marks were then glued in with medium viscosity super glue and were cut and sanded to be flush. At this point finish can be applied to the fretboard. I used Odie's oil to finish both the fretboard and frets.
Measuring using calipers from the back of the nut mark and punch the holes for the tuners. After this drill out he holes using progressively larger drill bits until the intended size is reached. You will need to use a piece of scrap wood to support and hold the top of the neck parallel to the plate as you drill. To drill the screw holes for my tuners I knew straight would be half an inch in from the outside. I placed a tuners on the hole and used my calipers set at half an inch to mark the point. I then punched and drilled the hole. I placed a piece of blue tape on the drill bit as a depth gauge to ensure I did not go through the front of the neck.
Bridge
Since the top of the guitar is radiused and bridge is flat before gluing the bottom of the bridge needs to match the curvature of the guitar. I taped sandpaper to a sheet of paper and placed it on the guitar. Holding the bridge in the middle I began to sand the bottom of the bridge periodically checking the curvature. Once it matched I sanded the bottom up to 220 grit to be glued on.
Mark exactly where you want the bridge relative to the nut. This might take a while but ensure your bridge is perfectly centered and the correct distance away from the nut. I used a bridge clamp that is simply a piece of metal with two holes on the inside. These line up with the holes in the bridge for the bridge pins. The outer two holes are threaded. Once the inner holes are attached using wing nuts on the inside of the guitar the outer screws are screwed down to provide clamping pressure to the outside of the bridge. I did a practice run before adding glue and it worked really well. Use cauls for the outer screws. More traditional looking clamps can also be used but they need to be very deep. If this method is used I would still suggest using the outer bridge pin holes to ensure the bridge does not move when clamped.
Once dry I drilled out the bridge holes to 3/16 of an inch and used a 3 degree reamer to add a taper to the holes matching my bridge pins. Be carefully with how much material you remove with tapered reamer. If to much material is removed the bridge pin will not fit tightly and come out when tuned. If this happens add a bit of blue tape to the bridge pin. Test fit with strings. Once this is completed oil can be added to the bridge being careful to not get any in the holes or on the bridge pins.
Final Steps
Fit nut and saddle to their slots. I bought them already intonated so I simply needed to make them fit. I sanded them to gain a perfect fit. Once you attach the strings you will want to check that the action (heigh between strings and fretboard) is about the height of a nickel. Sand the height of the saddle accordingly.
My neck is glued on using Titebond 1 because it is theoretically removable. I did a few practice runs before gluing on my neck. Once I ensured the fit was good I glued the neck on adding glue to the mortise, tenon, and area under the fretboard. My primary means of clamping the neck were the bolts going through the mortise and tenon. I also added a clamp through the sound hole on the front of the fretboard with a caul to help hold it down. Once this is dry add some strings and start playing!
Other Reasources
I primarily learned to build my guitar from these two resources.
I have wanted this video in full upwards of 7 times and have gone back countless times to see how he did certain stuff - https://www.youtube.com/watch?v=Dj5RewW11uM&pp=ygURYnVpbGRpbmcgYSBndWl0YXI%3D
Direct instructions on how to complete certain steps - https://www.instructables.com/Building-an-Acoustic-Guitar-1/
If you know someone who has built a guitar go talk to them. Most of the my guitar specific tools came from my friend who had already built one about 10 years before. I hope reading this has made you decide to build a guitar. It is a really fun project.