|
FIND YOUR CENTER (MANTRA-LESS)
Find the center of the back
of the instrument by measuring the widest points of the upper, lower and
C-bouts, dividing these in half and marking those points, lightly, in
pencil, on the back of the instrument. Visually line these points
up with a straight edge, and lightly mark this line on the button.
If God loves you, the center line on the button will correspond to the
center seam on your two-piece back.
Find the center of the top of
the instrument by measuring the widest point of the upper and lower
bouts, the distance between the proximal border of the upper lobes of
the ffs, and the distance between the proximal borders of the connecting
bars of the ffs, just above the notches. As above,
divide these each in half, and lightly mark the points in pencil on the
top. If you've done everything right and kept your alcohol
consumption to a moderate level throughout the construction process up
to this point in time, chances are still pretty good that all four of
these points aren't going to line up anyway. The two most
important references are the mid points between the upper lobes, and the
notches. Connect these points with a straight edge, and mark the
resultant center at the top edge of the instrument. This point
will always correspond perfectly with the center of the back.
With the center of the button
established, you can use a pair of dividers to lay out the
button.
DIMENSIONS
Use a knife to carve the button to within 1mm of its finished dimensions.
Use a divider to find the
center of the neck foot just below the FB. Extend this down the
neck foot with a square, and use the divider to lay out the width of the
button at the bottom (posterior aspect) of the neck foot. Allow an
extra 1mm on each side for the time being. Use a straight edge and
draw a line connecting the points representing the lateral margins of
the button with the sides of the FB. The wood on the lateral sides of the neck foot now needs to be hogged
off. This can be best accomplished with an in-canal gouge, broad
chisel, or an idiot chisel. Use the lines just marked on the
inferior of the neck foot for a guide. Also use the lateral edges
of the FB when viewed from the front to guide your cuts. Switch to
a block plane when you're within 2mm of the finished dimension.
The sides of the neck foot need to be perfectly flat. Check
frequently with a straight edge to see that they are. Not only do
they need to be flat, but they also have to be parallel to the lateral
edges of the FB (when viewed from the anterior aspect of the
instrument). By leaving the posterior angle 1-2mm wide of the
layout lines at this point, you can buy yourself some "wiggle
room" when fitting the neck foot to the mortice later
on. Set-up
of the instrument really begins with the layout of the neck, and it's
one of two areas (the other being fitting of the bass bar) where Terry
devotes a great deal of time and attention to detail. Having
said this, we concede that it's really easy to screw up. Keep the
following in mind: 1) under ideal circumstances, all points on the
center lines of the top and back will line up
perfectly. 2) these
ideal circumstances will never occur. 3) when establishing the
location of the neck mortice in the body of the instrument, the
center
line of the top (between both upper lobes and connecting bars of ffs)
is more
important for the layout than the center line of the back.
On a one piece back this doesn't matter because there is no visual
center line caused by the center seam of the back. On a two piece
back however, if the line-up of the neck set deviates from the center
seam of the back, it is glaringly obvious. In cases where this
occurs, it is possible to adjust the angles on the layout of the neck
foot so that the center of the FB aligns with the center of the top, and
the center seam of the back still appears to be the center of the
neck foot. <<THIS JUST SCREAMS FOR AN
ILLUSTRATION>> 4)
if you thought all of that was complicated, just wait. When
transferring the width of the neck foot to the corpus of the instrument,
we are going to deviate .5mm from the center line of the top toward the
treble side of the instrument. This eases play by slightly
displacing the FB toward the player's hand. |