Blocks, Ribs, and Other Actual Violin Parts!

The blocks are the very first pieces to be made that will remain a part of the finished violin. They are pieces of willow (Amati and other makers would have used spruce) that are cut along the grain, planed square and glued to the mould in a particular orientation according to the grain direction. Bonus points for spotting the block that is wrongly oriented:

Image

After the blocks are glued on, the template is used to lay out the shape of the corners:

Image

We’ll follow this particular corner block thru the process. First to be carved away is the inside curve of the C-bout. The outside curve remains uncarved at this point, so a nice rib miter can be made later, and also to give support while clamping the C-bout rib.

Image

Now the c-bout ribs can be bent to fit the mould (more about bending ribs soon…) and glued to the blocks. Glue is applied only to the surfaces where the rib meets the willow block. The ribs are clamped in place with counter-forms made to correspond to the curves of the ribs. Thanks to Minneapolis violinmaker Bill Scott for this clamping method using radiator hose clamps:

Image

The hose-clamp application is a modern version of the classic method of lashing the counterforms to the blocks with string and dowels (which is somewhat more photogenic):
Image

Next the outside curves of the corner blocks can be carved. The ends of the c-bout ribs are carved in a way that continues the line drawn on by the template. This will allow for that neat, tight rib miter:

Image

Image

Now the ribs of the upper and lower bouts can be bent. The next photo finally illustrates the rib-bending process a little better. Please forgive the chronology-challenged post. Like i said, i’m only human.
Anyway, the ribs are strips of maple (often from the same piece of wood as the back plate) that are thinned to a consistent 1mm.
The ribs are dampened with water and held against a hot iron. The heat from the iron drives the moisture thru the wood until it becomes flexible, essentially steam-bending the wood. If the wood is bent at just the right time in this heating, it is pliable enough to bend to shape without cracking, and will retain its shape once it cools.
The metal strap is used to further prevent the wood from cracking, especially in the tightest of the bends.

Image

If everything goes well, the wood holds its shape remarkably well…

Image

…so well that some alternative methods of construction forego the wooden mould altogether, bending the ribs freehand to a desired shape. This is also how guitar sides are often bent.

Image

Once the bending is finalized, the rest of the ribs can be glued similarly to the c-bouts. Tailor-cut counter-forms are again used to clamp everything in place.

Image

The ribs, being only 1mm thick, don’t provide much in the way of a gluing surface to attach the top and back plates, and so we bend and install 2mm-thick strips of willow, called “linings” along the inside of the entire outline.
The c-bout linings are inserted into mortises cut into the blocks to prevent them from pulling away from the ribs should the glue deteriorate. If this were to happen, it could cause a nasty buzzing while playing, which could only be remedied by taking the instrument back apart. This system also adds strength to allow for the flexing of the ribs while the mould is removed later on.

Image

The linings are glued with homemade clamps made from clothespins and bike inner-tube:

Image

Once the linings are trimmed down flush to the rib surface, and the miters of the rib corners are cut to their proper length (and angle), the rib structure is more or less complete.

Image

All that remains is to ensure that the rib structure sits flat on a flat surface. A flat stone, machined metal or flat glass plate are used to check that the assembly doesn’t have any high points or dips. This ensures that the eventual glue seam between the ribs and plates will have as little undue stress as possible.

Templates, Moulds, and Other Useful Violin-Shaped Things…

Once the outline has been drawn, we can make a template. The template is made from thin aluminium, which is demensionally stable and rigid, but also very workable.

Image

Since the drawing is symmetrical, in order to make the mould symmetrical as well, we can make a half-template. First, half of the drawing is cut away and glued to a piece of aluminium. Two holes are drilled along the violin’s center line so that the template can be flipped back and forth to correspond to each side of the instrument. The template is then used on a router with a duplicating bit to produce a wooden mould of the same dimensions.

Image

After the shape is established, the cutouts to accept the corner blocks and end blocks are cut, as are several circular cutouts to facilitate clamping later on.

The mould is ready for the first pieces that actually stay with the violin: THE BLOCKS!

IMG_1497

Next time, more words, more pictures…