Mark (TheCraftsmansPath.com) on March 19th, 2008

The first step in building the Dreadnought Guitar was to start assembling the body. This involved the two sides of the guitar, the tail block, the neck block and the kerfed linings that run around both the top and bottom edges of the sides and serve as a gluing surface later.

Assembling the sides

Guitar_Sides_Back_Blocks.JPGNeck_Block_in_position.JPGThe two Rosewood guitar sides are connected with to two Mahogany blocks. One block for the tail of the guitar and one for the neck location. The neck block has a mortise for a bolt on neck (some guitars may use a single large dovetail joint here). The tail block is just a raduised solid block to match the curvature of the sides. These two blocks must be glued to the the sides precisely at the center of the body and as square as possible to the edges of the sides. This is especially true of the neck block because this setup determines the eventual set of the neck on the guitar. Because the neck block must eventually be glued to the guitar back and top, it must match also the angles formed by back and top. So, it is machined with a 5 degree bevel to match the back and a 1.5 degree bevel to match the top.

Neck_Block_recess.JPGGuitar_Sides_Weighted_Down.JPGThe two guitar sides are machined flat on the top edge and have a radius on the back edge. To start the assembly, the centers of both the neck and tail blocks were marked with a pencil. The pattern of the top of neck block was outlined with a knife through just the top layer on a piece of cardboard. This relief was created so that the 1.5 degree bevel of the neck block could extend below the cardboard surface allowing the block to sit square to the workboard. The sides were placed flat side (top) down on the cardboard and the blocks were aligned to match up with the seams created by the sides. It took a few dry fits to align the seams as well as the top and bottom edges of the blocks with the sides. After these dry fits it was time to do the glue up. This started with weighting down the sides so that they would remain stable during the glue up.

Clamping_Heel_Block.JPGClamping_Neck_block.JPGGuitar_Sides_and_blocks_glued.JPGThe tail block was glued first (with the neck block just dry clamped to the sides). As you can see this took quite a few clamps in a small space – two of these needed extra deep capacity as well (it looks like some creative clamping solutions may be necessary before this project is completed). Gluing the neck block followed once the tail block assembly was dry. Again, a lot of clamps and extra attention to detail were required to get the neck block set as precisely as possible so that the eventual neck set on the guitar will go smoothly. We’ll have to wait until later in the project to see how well I did in that department! In the picture you can see the completed glue up of the neck block, the tail block and the sides. Also in the background are some parts of the cardboard form which I’ll talk about next.

Building the cardboard form and waist clamp

Often, guitars are built using a specialized workboard or custom wooden form. The kit that I started with has a very economical way of creating a workboard and form. This was done with a flat workboard, two cardboard cutouts that mirror the shape of the guitar body, a couple of wood blocks and a shop made waist clamp.

Internal_cardboard_form.JPGGuitar_Form_with_waist_clamp.JPGThe two cardboard pieces were cut to match the shape of the guitar body. The first piece was inserted into the body over two scrap pieces of 3/4″ material. This was done to elevate the cardboard so that there would be room to attach the kerfed linings to the edge of the sides later. I made a couple of wooden blocks to stand off the second piece of cardboard from the first. One block in the upper bout of the guitar (the smaller section of the body) was 2″ high and the second block in the lower bout was 2 1/2″ high. This offset is because the body actually has a taper – the body is deeper at the bottom than at the top. The blocks were glued to the lower piece of cardboard and then the top piece of cardboard was inserted and glued to the blocks as well.

The second part of the form is a shop made clamp that slides over the waist area of the guitar body to keep things stable. I built this clamp from some scrap MDF. I simply cut the shape out on the band saw and then radiused the inner edges so that it would slide snugly over the waist without cracking the sides. With the inner cardboard form and the waist clamp installed, the assembly was fairly rigid. At least, rigid enough for the next step.

Attaching the kerfed linings

The top and bottom edges of the sides require some material to be applied to both support the guitar body as well as to add a gluing surface for both the top and back of the guitar later. Because of the curves in the sides of the guitar, these linings are kerfed with a narrow saw cut at even intervals so that they can bend with the shape of the guitar. The linings were not long enough to make it around an entire side of the guitar so they were installed in two pieces.

Gluing_Kerfed_Linings.JPGCompleted_Kerfed_Lining_glueup.JPGThe kerfed linings needed to be attached about 1/32″ of an inch above the guitar sides. This was done so that they can be sanded flush to the top and bottom at the appropriate angles later. It does not require much pressure to clamp these linings to the sides. So, as you can see they were clamped using ordinary clothes pins – though, there were a lot of them! This was done by simply applying a sparing amount of glue to the backside of the lining and then applying the clamps one by one, carefully aligning the edges (1/32″ proud) and making sure that there were no gaps between the lining and the guitar sides. As I mentioned, two kerfed linings were required for each side (top and bottom) for a total of eight linings. In the photo you can see the the glued up body with the completed linings.

Just a note about glue. As you can see in the picture, I am using original Titebond I for this project. Traditionally a luthier would use Hot Hide glue for an instrument. This is done both for its strength as well as its reversibility (i.e. the ability to take a joint apart later if necessary). It is also important to use a glue that creates a very rigid glue line and does not exhibit any creep while making an instrument. Hot Hide glue has all of these properties. Liquid Hide glue is kept in a liquid state by adding Urea and as a result looses some of its strength making it useless for an instrument project. I do not typically work with Hot Hide Glue so I chose the next best choice, Titebond I. Titebond I is the best choice of the aliphatic resin glues for instrument making. It is not nearly as reversable as Hot Hide glue but, it can be reversed. Where Titebond I is better than other versions of Titebond is in the glue joint it produces – it is very rigid and does not exhibit creep. This will ultimately result in a stronger and better sounding instrument.

10 Responses to “Dreadnought Guitar: Assembling the sides and kerfed linings”

  1. Mark,

    This is just like watching Handmade Music, right down to the clothes pins – I love your first installment!

    1. I am already anxious to see how well the neck goes on ;-)

    2. Why is the body deeper at the bottom than at the top? Is it somehow related to sound quality?

    3. I bet you are glad that Titebond 1 is a good alternative. I think it would not be fun working with hot hide glue.

    A great start, Mark. I look forward to the entire series.

  2. Hi Al,

    Thanks for visiting. Yeah, I guess in this case clothespins are your best friend in the woodshop!

    The build is going well so far, though I think I will need to build some specialized clamping capability for the next steps of attaching the bracing for the top and back. You’ll have to keep watching for the neck work – that won’t come for a while yet.

    The body is actually deeper in the lower bout and also radiused in both directions on the back (all the braced have a curve on them). The top is also radiused to a lesser degree. This is why I will need a creative clamping setup for the braces. All guitars are different, but it all relates to sound in the end.

    I contemplated using Hot Hide glue for the things that might reasonably need to be reset on the guitar at some point in its life (i.e. bridge, neck, etc.) But, since this is my first and Titebond I is a reasonable alternative I just went with it. Many people build exclusively with it.

    –Mark

  3. This brings back memories.

    For gluing braces to the top/back. consider making a go bar clamp.

    http://www.lmii.com/CartTwo/th.....bar+Clamps

    They are easy to make and can also be used to glue the top/back to the sides.

    As for the profile on the sides, the taper is so the sound is moved from the lower part of the instrument towards the sound hole and out to peoples ears.

  4. Eric,

    Hopefully the memories are good ones ;-)

    Already ahead of you on the clamping solution. You should see evidence of it in the next post on this project.

    Good points on the depth of the lower bout vs. the upper bout and how that helps project the sound from the guitar.

    –Mark

  5. As far as the go-bar deck goes, one can be easily made fairly cheaply with some plywood and construction grade lumber. The go-bar sticks can be made from fiberglass rod or 1/2″ x 1/4″ strips of maple or a similar stable hardwood. I just completed construction of my first acoustic guitar, a slope-shoulder dreadnought and I’ve outlined most of the progress on my blog at http://redsguitars.blogspot.com. All it needs is some sanding, a finish, frets, a bridge, nut, and saddle to be playable. It is a very rewarding process and exciting to see a guitar take shape. Good luck with the project!

  6. Jason,

    Thanks for your comments.

    Actually I’ve already built one – should have some info in an upcoming post. You are right, it is a fairly simple process. I’ve tried the wooden go-bar clamps, but I’m thinking that I may look for fiberglass – what diameter fiberglass did you use?

    So far, the process of building the guitar has been very interesting and fun. Thanks for stopping by and please continue to visit and comment.

    –Mark

  7. Hi Mark……………..this is really cool. I forwarded your address to my brother….he’s in a “finally got the time to be Stevie Ray Vaugh” phase and loving it. I know he’ll enjoy seeing your progress.

    What I thought interesting was the kerf linings, for some reason I always envisioned them going full length. Are the Rosewood bends strong enough to take a tossing before assembly???? Did you have to square them up or were they “rough squared” in the kit????

    This should be fun to watch. Of course we all expect a short audio for our listening pleasure on completion. Maybe some Hot Tuns’a …Water Song????? :)

    I see you over at Rough Cut, I’d love to see you comment through-out T-Mac’s forum project build, you have very good quality thoughts on all this internet woodworking stuff. I see participation more than those just building.

    Neil

  8. Hey Neil,

    Thanks for stopping by. Hope your brother enjoys watching the process.

    The kerfed linings just reinforce and add glue surface to the joint between the top/back and sides. The sides will be further reinforced between the kerfed linings with the vertical strips of spruce later after the inside mold is removed from the body. Not sure what you are asking about with respect to squaring up…one edge (top) of the sides is straight and the back edge is radiused along the length of the guitar so, that makes things a bit more challenging.

    With respect to the Rough Cut forum project, I am contemplating trying to do the build. I have not done a Federal piece but, I had been contemplating doing one at some point soon – I really like that style. If I can schedule it in, I think it would be interesting to do and to blog about here.

    –Mark

  9. The fiberglass rod I use is a 3/16″ diameter and I have little plastic caps on the ends, but I’m not sure where a local place to find them would be since I ordered my supplies online. I have also used the maple strips and both seem to work equally.

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