Saturday, February 8, 2014

Acoustic Progress -- Part Six

Although I like 'simple', when it comes to project detail, I've found that complications pop up regularly in the world of luthery.

Since the last post about my venture into the acoustic guitar-building arena, I've learned a lot more about the building process; how additional specialty tools aid the process; and how current eco-unfriendly government restrictions cause unplanned delays.  But, Uncle Sam's Postal Service saved the day (I'll explain this later), so I don't want to hear any complaining about how you didn't receive Aunt Willa's birthday card on time.

So, just what have I been up to?

After gluing up the body, the neck was the next order of business.  This is one of the most crucial elements in the building process (how do I know?, because my friends at Martin Guitar are so willing to share advice and information), because, if the angles of the heel and neck are not perfect nothing else will align properly and string action will be lousy.  I follow the 'measure twice (or more) and cut once' theory, always, and it works!  The angle alignments are spot-on Martin recommendations.

With the bare neck attached to the body and flush with the top, a straight-edge rule lying flush with the neck surface will ideally be 1/16" - 3/32" off the body surface at the point where the saddle will be positioned on the body. To achieve this, the heel (where the neck meets the body vertically) must be carefully shaved to fit.  And, this is only the start.  The center line of the neck must also be in alignment with the center line of the body.  So, one side of the heel may need to be shaved more than the other, while maintaining vertical integrity.

In the photo above, you'll notice a cavity running the length of the neck, which is the channel for the truss rod.

In the photo to the left, the truss rod is in place, sitting flush with the top of the neck.

The rod is shrink wrapped in a vinyl film for a reason -- to prevent the epoxy resin used to glue it in place from seeping into the rod's movable parts and rendering it useless for possible neck adjustment, down the road.

Next comes attaching the fingerboard to the neck.  This can be done in a couple ways, but the 'simple' rule applies -- press in the frets and dress them prior to gluing the board in place.  Why?  Because, it would be easy to snap off the portion of the fingerboard where it overlaps the heel, if the board were to be glued on prior to setting the frets.

Pressing the frets into the fingerboard is my method of choice.  Many luthiers recommend using a brass hammer to do this, but I don't subscribe to the notion that banging around on critical pieces is the solution to task.  So, I simply (there it is again, 'simple') cut a piece of oak scrap to the contour of the fret board; drilled a hole in the middle of the die and glued in a steel rod, to create a fret press that would fit my drill press.  Then I ran the bulk fret stock through my 'cheapo' home-made fret wire bender; cut it to length for each fret slot; pressed the wire in place; dressed the protruding ends with a file; finished the process with a fret file and steel wool, and voila, a completed fret board ready to be glued to the neck.

Whoa, gluing the fingerboard to the neck is a little more difficult than slapping one board on another and tossing a rock on it for weight.

The headstock is at an angle.  The back of the neck is rounded off.  The heel extends downward and is curved.

I need a new tool!  As you can see, I created a simple jig to hold the neck in place, while a sturdy board rests on the top of the fretboard for adjustable clamps to apply pressure without damaging the surface of the board. This took me all of thirty minutes to build from scrap stock laying around the shop gathering dust.  Damn, I like it when a plan comes together!

When the glue dries, I'll be ready to move on to the next phase of the acoustic dream.  Stay tuned for more progress.

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