THE RIBS.
The thickness, but more especially the depth of these, is of much
consequence in relation to strength and quality of tone. I have
found a bare sixteenth of an inch answer very well for thickness,
and on the model I have worked on before you, in depth one and a
quarter of an inch at lower or broad end, gradually narrowing to one
and one-eighth full at the narrow.
Now, take the thickness for granted; but follow me very closely
while I describe to you how I arrive at the depth being just what I
want and sought for to obtain the note B _before_ the soundpost is
inserted, when you blow in the _f_, C, _after_ it is fixed. Of
course, this is making the scientific part of the work, or one of
them of no sort of anxiety to you, being already done by me at no
little trouble and much thought; but, as I set out as a teacher, if
only of moderate calibre, I shall go through with my endeavour to
make some good workmen out of my listeners and readers, therefore
you are welcome to what is, I think, of importance, never minding
what will be said at the outset, that all this fuss is somewhat of
nonsense, seeing that it was _so_ easy to copy the depth of a rib,
and get to what was wanted and avoid it. But I do not like copying
where I can help it; besides, what I shall lay before you has the
merit of getting at what you want to a nicety, and of finding out
what depth of rib will suit the model in hand, and obtaining the
mass of air of which I before spoke.
On a finished back, just like the one which we have before us, I
fitted a set of ribs about one inch deep to three-quarter inch
taper, and on a similar belly to this, another set of like depth;
but I so arranged that those on the back should be one thirty-second
more _out_ than usual--that is to say, nearer the edges of the
wood--and those on the belly one thirty-second more _in_, or away
from those edges. Then, after filing and scraping for a long time,
I, with no little patience withal, contrived so that I fitted one
set over the other of the ribs, (as a double box) and got a sort of
fiddle body, clumsy of course, but I saw my way to doing just what I
had set out to do, and I did it eventually.
Gradually shallowing the ribs by lowering belly or raising back, I
got various tones or notes for the air mass, trying E, D, C, B, A,
but no resonance such as that of B suited me, so I roughly glued
these ribs firmly together, fitted up the whole thing with every
accessory such as would allow me to play on the instrument, with the
satisfactory result of proving a case beyond question.
So I get to the necessary and somewhat difficult process of making
the ribs, etc. But the mould in which they are to be temporarily
fixed must be first made by you, and this is the way to go about it.
Get a piece of dry beech--birch or maple of the plain sort will
do--18 inches long, 7 inches broad, and 1-1/2 inches deep. Take the
half outline of the violin which you have decided to make, and place
it flush with the edge of the above block, equal spaces being left
at either end. Then very firmly and very accurately draw the half
outline on the block for your mould. After you have done this, you
must trace an _inner_ line all round the other, one-eighth of an
inch from the real outline; and, when you get to the corners, carry
this inner line to a broad, open point somewhat beyond the square of
the corners, as by this you are enabled to pass your ribs a little
over the terminus at said corners, which will most materially assist
you to effect a good joint there.
After this is well done, and your under surface quite level with the
plane, take the block to a good band sawyer, and get him to saw
_just through_ the inner line, and you will have your mould in a
measure ready for your ribs. Still, there is something to be done
before you can set to work to fashion them, and the first is, square
after the fret saw every quarter inch of its work, with steel
square, 60, on tool block, your basis being your planed under
surface, as most reliable.
Then, about one inch from inner mould, and one inch apart all round,
drill holes through the wood with tool 56, or similar; and three
larger holes, about seven-eighth inch diameter, one and a quarter
inches under the centre of the D or middle bout, the other two some
distance under the two corners. The small holes are for the bent
steel cramps 2 to hold by when the linings are being fixed to the
ribs, etc., and the three larger ones to hold down the centre rib in
the same way by means of fitted wood block 33, and for the corner
blocks, when they are fitted properly to the shaped ribs. (Cramp 11
is used in these latter cases.)
Having the mould ready, and in good order, prepare your ribs in this
manner:--selecting what is nearest in figure to the back--good,
honest wood--dress down both sides of it, the outer to a more
finished surface, of course, and cut them to the dimensions
previously stated, viz., one and a quarter inches to one and
one-eighth of an inch whole length; but this whole length you will
have to determine by measurement of each separate bout--lower,
middle, and upper--which, when done to a nicety, mark on respective
bouts for all future guidance in exact length.
When finally dressed, cut into lengths, and the ends of the middle
rib filed down so as to enable the ends to pass and join upper or
lower bout as the case may be, they being filed to fit, put your
heating iron, fig. 5, and another iron to match, so that you will
have a reserve of heat always on hand, into a bright, if possible
smokeless, fire, and from one to the second of the heaters, get a
good hot temperature--not scorching, be sure--and place a piece of
brown paper over the narrow end of the heated tube. Then hold tool
64 in your right hand, middle rib in the left, and, with one end on
the brown paper, the tool on that, very gently, cautiously, and by
intuition, as it were, _feel_ your way to a sweet curve of upper
corner, using the broad part of the iron for the lower. Of course,
although I have not told you, you will have bent the wood _face to
the mould_ for this centre, as the reverse for the outer, or larger
ones, naturally. This done to your mind--do not be discouraged when
I say I hope it _may_ be--for you have hot work before you in more
ways than one--get to the sharp corner curves of both the other
ribs, face against iron afterwards, inside against it. Mind, as is
your true shape to mould, so will your ribs be when it comes to be
attached to the back; and there is no patching or trickery allowed
here; so do your best. After this, fix the three sections into the
mould, and keep them in position by means of cramp 2, and the centre
one with block 33, held firmly by cramp 11.
Your corner blocks must be a trifle broader than the ribs, and about
as wide as them--also from corner to inner surface, about one and a
half inches. Cut and fit these nicely for future glueing, and then
prepare and bend your pine for linings. This pine must be about
five-sixteenths of an inch broad by about three-thirty-seconds of an
inch thick, cut to taper for inner dressing either before or after
fixing to ribs. These are not too easily bent, but not nearly so
difficult as the ribs; but do not put on too much pressure, or snap
is the result.
It will be necessary to see carefully to the gradation of the depth
of the ribs from one and a quarter inches to one and one-eighth of
an inch, either when they spring from a whole length or from three
separate ones. In any case, my advice is to mark the beginning and
end of each section from the broad end to the narrow, Nos. 1 to 2,
lower; 2 to 3, middle; 3 to 4, upper; so that you cannot well get
wrong in bending, from which would spring the first cause of error.
Having your glue somewhat thin but firm, at the point of setting,
glue and clamp well your corner blocks (your mould being in the
vice) and after that, remove the fitted wood block over the centre
rib (it being now fast at both ends by means of the blocks just
glued), and accurately fit the two small linings there, removing
each end of said lining between block and rib, at either end, and,
by first forcing half-inch chisel where the lining will have to go,
as a sort of slot. This you must also do at the ends of all the
other linings. Now glue the two small ones for centre and carefully
fit and force them end by end into slots, finally placing wood block
33 over glued linings, and clamp firmly with cramp 11. The other
four are much easier to fit and fix; small cramp 2 being used; but
here you must always be sure of a perfect fit all over, or you will
find when taken from the mould there will be apertures, Fig. 16.
[Illustration: PLATE XVI.]
When dry next day, and before you take from the mould, remove most
of the cramps (one or two being left to keep the work fixed) and
very neatly cut and clean all the work, as shown in figure of open
instrument, and go about it in this manner:--the heavy corner blocks
must be reduced with large gouge, and the linings made to fall away
from their _full_ thickness at edge of ribs to fine union with said
ribs at the extreme of their (the linings) width. After that, clean
every atom of superfluous glue away, and finish off with two or even
three courses of sandpaper, rough to fine.
Then remove these so far finished ribs, and take the knife 19, being
made by you exceedingly keen of edge, and square both edges all
over, so accurately that, when they are glued later on to the back
and belly, they shall fit and well, being jointed so that no
aperture whatever is apparent.
But, you will doubtless murmur, it is all very well to _say_ all
this--please show us how to _do_ it all; for, on the face of it,
this is no child's play. And you are right to speak out; for it is
one of the most difficult points we have to master, and I fully
intended to make it quite clear before leaving it.
Hold the rib by left hand firmly to your breast, face side to you.
Then take the knife 19, and cut away the superfluous linings and
corner block wood, holding the steel absolutely square with the rib,
or you will be all abroad. It is this squareness that is the severe
test and your great trouble just now. Try on anything and on
everything before you try it on a rib you may spoil; but _do_ it on
something or other, and finally you will do it and well on these
ribs.
But, after cutting, you will have still more to do--lay them flat
and keep them so and rigid with left hand whilst you, with rasp 47,
fine side, level from one end to the other, _not from_ you across
the rib, as the other way is safer for keeping square, and obviates
the risk of tearing away part of a lining or slip from a corner
block.
You will have dressed the ribs at the outset as instructed; but you
will now find them anything but fit to attach to the back; so trim
and make them free from any blemish or stain of dirt, and then do
your best to fit one side accurately, so that, when glued
afterwards, there may be no discrepancies nor goings back.