Monday, December 28, 2009

Shaping the Neck

With the fretboard glued on, it's time to shape the neck.  I start by bandsawing the excess neck wood close to the fretboard, and then use a rasp and scraper to get the sides of the neck even with the fretboard.

Before shaping the neck I need to finish shaping the heel.  I rough shaped it back when I was fitting the neck to the body and working on the neck angle, but I need to finish it now.  This is chisel, rasp and sandpaper work.


Now on to the rest of the neck.  There are a number of different methods of shaping the neck; this is the way that I was taught.

At the first and ninth frets I measure both the thickness of the neck and the width of the neck.  Remember, the neck gets both thicker and wider as you go toward the body, and I want a nice, round neck all the way down.

I transfer these measurements to a piece of paper, drawing a rectangle with the height representing the neck thickness and the width representing the neck width.    Then, using a compass I draw a half circle that touches both lines.  This represents the back of the neck, with the bottom line representing the fretboard.  So what I have drawn is the neck in cross section.  The rectangle is the neck as it currently is shaped, and the half circle is the neck as I want it to be shaped.

I add a centerline, then draw a line tangent to the circle at a 45 degree angle from the centerline.  I measure the distance from the centerline to where the tangent crosses the line representing the back of the neck, and also the distance from the fretboard to where the tangent crosses the side of the neck.

I do the same for the ninth fret:

I transfer these marks to both sides of the neck and draw a line connecting the marks at the first fret with those at the ninth.  The material between these marks is not neck material and needs to be removed.

I hog off material using a spokeshave, then take it closer to the lines using a rasp (which you can partly see in the left of the picture.)

So I've taken a rectangular piece of wood with two corners at the back of the neck and removed the corners, creating two facets with two corners for each facet.  I go back to the diagram and use the same procedure to removed these corners, transferring measurements to the neck, connecting lines, and using the rasp to creating removed material that is not part of the neck.

I put the rasp away and use a scraper to removed these corners, then 100 grit sandpaper to smooth everything out and get to the final shape.  At this point it's all looks and feel.  I look at the neck to see obvious high points, and run my finger along the neck to feel for smaller high points.

As the neck approaches its final shape, I pick it up often and hold it in playing position, seeing how it feels at various points but paying close attention to how it feels at the first fret--open position, where most of the playing is done--and down at the heel where the cutaway is.

After making some final adjustments at the heel area and also where the neck transitions to the headstock, I'm satisfied, and we've got something that looks a lot like a guitar!  Here are some pics:



Next up is doming the fretboard and installing the frets.  We're getting close!

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