A reader asked me for some details about the bracing of the 1838 Laprevotte that I had in the shop some time ago.  Here is the information I was able to offer.  Remember that Laprevotte was a violin maker before he turned to guitars and another thing I like to keep in mind is that there are makers using this kind of bracing today who claim that they invented it, ha ha.

All measurements in mm.

There are four parallel longitudinal bars which I will number starting from the extreme treble side.  Number two is 38.5 from the centre line and number one is 37.5 from number two.  Number 3 is 42 from the centre line and number 4 is 35 from number 3. There are also four short cross bars between the two centre bars whose positions I measured from the 12th fret position.  Number 1 is at 60, number 2 is at 96, number 3 is at 280 and number 4 is at 388.

Back to the longitudinal bars, they are scalloped at the ends and are peaked gradually as opposed to being rectangular and simply rounded on the top.  The heights are Bar 1 ub (upperbout end) 7 and lb (lowerbout end) 8, Bar 2 ub 11.5 and lb 14,3, Bar 3 ub 12 and lb 14.3, Bar 4 ub 7.5 and lb 7.55.

The widths are Bar 1 3.5, Bar 2 increases from 3.5 ub to 4.5 lb, Bar 3 is 5.5, Bar 4 is 4.5.  Both Bars 2 and 3 seem to tuck under the neckblock and the endblock whereas Bars 1 and 4 either end at the linings or are also let in to the linings.  Here are the heights of the bars where they “end” after scalloping.

B1 ub 3.75 lb 3
B2 ub 4.2 lb 5
B3 ub 4.2 lb 5.35
B4 ub 3.8 lb 6

The length of the scallops:  Bars 2 and 3 are scalloped from the position of the nearest cross bar to each end.
B1 ub 42 lb 28.4
B4 ub 41 lb 49

The short cross bars are 7.5 high and 3.5 wide except for the one in between bridge and soundhole which is 4 wide.