Acoustic Guitar Build

Alex Reid

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Zushi, Japan
As I mentioned in this thread I will start an acoustic guitar build. I am already about 1 month into it and already have the top plate completed. But I am going to start here from the beginning. I wanted to get a blog setup on my site before I start but was unable to get it going this week.

This I my first time to build an acoustic stringed instrument. For this I am using several books for reference, Youtube videos and online forums like Musical Instrument Makers Forum. I am using the plans from Jonathan Kinkead's book, Build Your own Acoustic Guitar. His plans are based on an early Martin (no more details provided) but it looks like an OM model.

OM stands for Orchestra model and they were produced in low numbers in the early days (early 30s) but have seen a resurgence in the last couple decades. Typically they have a longer neck, smaller body with a slightly higher waist. My kind of gal :D.

There are several good kits available through stores like Stewart MacDonald and Luthiers Mercantile International. The kits are high quality and can make many of the steps much simpler but I wanted to make one from scratch building all the templates, jigs and using traditional timber species for a steel stringed guitar.

For this build I am using Sitka spruce, Indian rosewood, Honduras mahogany and African ebony.


I'll begin in the next post with making the template for the top and back.
 

Alex Reid

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739
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Zushi, Japan
Making a Template for the top and back plate.

The plans


The plans cut out and folded in half with number 1 plate template made from 6mm ply.


Screw the template to a rough cut of ply mark your center line clearly from top to bottom and route the edge clean. Make sure you mark a cross point midway in your center line for lining up when you flip over and do the same on the opposite side.


Cross point midway in your center line.


Remove the half plate and there you have your top and back plate template. These two templates (half plate and full plate) will also be used for making your side bending jig and the body mold.


Check for accuracy.
 
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Alex Reid

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739
Location
Zushi, Japan
Acoustic Guitar Build - Plate Glue-up

Well finally got the time to post the next step. Been busy all week with firewood and other things.

In this step I will glue up the top plate. I am using Sitka Spruce. It is Grade AAAA so it has some fine grain in it with a little, what is referred to as, bear claw grain pattern.

I bought the plates from a luthier supplier so they come sized and thicknessed to 3.5mm. There is not much to work with here as I will take them down to just under 3mm.

For now though I will only put a jointed edge on one side with my jointer, clean up the edge with a straight edge sanding and then proceed to the glue-up.

For the first step I tape the ends and put them through the jointer together in their bookmatch form (not pictured). This is something I always do when doing any bookmatch work.

I then clamp a board to my bench with one plate trailing over the edge. You can do two plates at once as the spruce is quite soft and sands quickly. If you do one at a time make sure you keep the plates in the bookmatch formation.


Take a straight edge, apply a strip of 180 or 240 grit sand paper to the edge and rake lengthwise, sanding along the plate edge. (I buy rolls of 3M sticky-on-one-side sand paper.)


Keep the level flat to the bench surface. When finished hold up to light and check for any gaps and quality of joint.


This is a standard butt joint so I put the two plates together, raised in the center with a 6mm thick board and some wax paper.


With the plates in position screw some blocks down to the work board keeping the plates snug together.


Apply glue to the jointed edge, pull out your stick in the center and gently press the two plates flat down onto the work board. Lay some more wax paper over top and clamp it down with some long reach clamps.


Keep it in the clamps for a few hours. I like to wait until the next day to do any work on this as the butt joint is only 3.5mm thick. So give the glue a full day to cure.
 

Vaughn McMillan

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I like the clamping trick, Alex. :thumb: How did you arrive at the 6mm height for the "lifter" board between the two plates? It seems if it was too high, you'd risk having the glue joint too tight and possibly warp or crack the plates. Too low, and the joint might not be tight enough. It looks like you knew the magic number.

And speaking of 6mm...I don't know if I could play a metric guitar...you know, with the first harmonic on the tenth fret and all. :rofl:
 

Alex Reid

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739
Location
Zushi, Japan
Actually Vaughn now that you mention it it is not only the 6mm height of stick but the width as well. In this case it was just a little trial and error to find the snug-fit butt joint.

As for the metric harmonic I think you have it wrong because the correct conversion is to multiply by 2.54 :rofl:
 

Brent Dowell

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Reno NV
Very cool trick. I see you have the requisite luthier clamps as well!

I love those clamps, they come in handy for all kinds of things... :thumb: :thumb:
 
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