Thursday, February 21, 2013

Building an Early Lacôte Guitar Part 3

Pat Bianculli's 1823 Lacote

The flush fingerboard of Pat Bianculli's Lacôte is a hold-over from baroque era in which it was important to keep the strings close to the soundboard. Utilizing a low bridge and a flush fingerboard accomplished this. I find it curious that this feature endured as long as it did. The transition to six single strings had started thirty years previous to this. The development of a saddle and fixed metal frets swiftly led to the raised fingerboard. Yet, guitar builders continued to use flush fingerboards even though it is a feature that made demands on musicians and luthiers alike. Perhaps guitarists and makers were hesitant to discard this feature because the aesthetics of both tone and sight were pleasing, evocative, intimate? I had not built this style of Lacôte before and that was the attraction for me.
Constructing a guitar with a flush fingerboard requires a particular sequence of assembly. This photo appeared in an earlier post but I am using it again to show that I had glued the fingerboard in place even before I started the purfling. This was necessary  because I needed to level the transition from the fingerboard to the soundboard before I assembled the purfling. Doing so afterward might have damaged the delicately mitred purfling corners. 

 I had also slotted the fingerboard previously and hamered in the frets. The edge of the last fingerboard fret is visible in the photo.

original bridge
The bridge on Pat's guitar was a replacement and seemed to be constructed a little larger than Lacôte's standard size.  

The front edge of Lacôte bridges are smoothly rounded with the saddle slot cut several millimeters in from the front edge. The saddle on the replacement bridge was cut considerably further in from the edge than normal.
I consulted my notes and museum plans and designed a bridge in the Lacôte size and style. When I make any bridge with a saddle I leave the front edge square and the top surface, where the saddle slot will be, flat.
I do this so I can work out the compensation of each string in order to achieve good intonation. I use triangular shaped pieces of nut  bone as movable saddles. Placing them on the surface that I had left flat I maneuvered them into positions that gave the correct intonation for each string. I duplicated these positions by angling the saddle slot from closest to the front of the bridge on the treble side to furtherest on the bass side. The finished saddle is 2mm wide so I will contour the top of the saddle to further refine the intonation on the finished instrument.

The last stage of the fretting was the most difficult to do, yet when finished, the most satisfying and visually one of the most pleasing features of this style of guitar.

On baroque era guitars the belly frets are slivers of ebony or boxwood glued on the surface, but sometimes inset, on the soundboard. Once metal frets were used on the fretboard they needed to be continued onto the soundboard for consistency of tone. Keep in mind that 19th century frets were not the T-shaped fret of our day but straight pieces of metal that were about 0.8mm thick. The spruce of the soundboard is too soft to support metal frets of any kind adequately. Lacôte bordered his bar frets with ebony. This ebony/metal fret/ebony sandwich is a little less than 3mm wide. I wanted to insure that my belly frets played in tune so my problem was how to inset a 3mm wide fret assembly in the soundboard precisely in the correct location.  
I laid out the fret positions in pencil and after double checking for accuracy I scribed over the pencil with a knife being careful to respect the length of each fret. Then I widened the scribe line with a razor saw and continued with successively thicker saws until I had broadened the original line to 0.9mm. This is the width necessary to press fit a T-fret into the soundboard. I still needed to add the ebony supports that were also 0.9mm wide. I cut pieces of a broken bandsaw that fit exactly in the fret slot but a little raised above the surface. I placed a piece of the ebony border against each side of the temporary metal "fret" and carefully scribed a thin knife line. This delineated the borders of the recess I would cut for the ebony/fret/ebony sandwich. The sequence of steps is demonstrated in the photo. Once everything was prepared I waxed the metal spacer and glued all three pieces into the slots.

When the glue dried I removed the metal spacers, planed the ebony flush with the soundboard and inserted the T-frets with a little glue.

Next time I'll explain the varnishing and post detail photos of the finished guitar.

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