Preparing the wood
 (image: 3.0

Choose good, well flamed wood which matches the pattern on the back of your violin as closely as possible.

Fix plane No. 7 upside down in your vice and plane one side of each of the ribs so that its level and straight.

Draw a maximum height line /+2mm safety margin/ parallel to the side you have just planed using a Vernier caliper. The maximum height is the maximum height of the ribs, usually in the back of the violin, ie. 32+2mm Messiah.

Either cut through the line using a knife and a steel ruler or plane the rib height to the line with the plane in the vice as mentioned previously, if the height is not too much.
 (image: 3.1

Now that you have all the ribs trued and cut to the correct height you need to adjust their thickness to approximately 1.5mm

To do that, it is advised to use a block plane with a blade reground for scraping as in fig.3.0.

Clamp the rib down to your bench and start planing away from the clamp.

After you have reduced the thickness to 1.5mm, continue removing material down to 1.2mm using a scraper. Make sure the thickness is evenly distributed along the whole length of the rib. You may need to tilt the scraper a little to avoid creating grooves as the flames tend to grab the scraper.

Cutting the blocks

Using a suitable gouge, start paring away the wood on the upper and lower corner blocks where the C ribs will be. The block you are working on must be resting on the surface of the workbench, otherwise it might snap off as it is only lightly glued. Make sure you`re not undercutting constantly checking with the contour line on the other side of the blocks. Also, keep checking everything is at right angle with the plane of the mould.

Finish with sanding paper on a stick, making sure that the point where the blocks meet the mould is as smooth as possible.

Pare away all the wood about 3mm beyond the projected tips of the corners.

Check the contour again by realigning the template with the mould.

C rib bending

Cut two lengths of rib stock and put them in water.

Screw the four screws in the mould again.

Heat up the bending iron and bend the C ribs so that they fit the mould as closely as possible.

For a test, put on the C rib clamping blocks and make sure they sit well, that they are perpendicular to the surface and that they end up a couple of mm proud of the tip of the corner. When pressure is applied they should be "opening" the C rib slightly.

If everything fits nicely, glue in using medium thickness hide glue.

Cutting the blocks

When the C ribs are completely dry, remove the excess height leaving them just a little proud of the blocks. As with the C ribs blocks, pare away the wood on the upper and lower corner blocks to the contour line and finish with sanding paper on a stick. The difference here is the need to create a feathering at the four ends of the C ribs.

Make sure the feathered tips end within 1mm of the tips of the corners on the copied violin. Check often with the template. Everything must be smooth and within parameters.

Top and bottom ribs gluing
 (image: 3.3

If you chose to make the bottom ribs in two parts, mark the center of the violin on them and saw off.

Use a small shooting board to plane the ends of the ribs down to the marked lines making sure, they are at right angle to the top and bottom of the ribs.

Align with the mould and see if the ends meet well. There should be no visible gap.

Put the ends one on top of the other, about 2-3mm in, and paste over with two patches of flexible tape.

Pull apart a little so that the ends meet again. Make sure all fits well.

Put some dry soap on the mould, except, of course the blocks.

Put some medium thickness glue on the bottom block and clamp down. The same goes for the lower corner blocks.

The upper bouts can also be two parts but there is no need to precisely pair them as the top is later on removed and the neck root inserted and glued in. The gap between the upper bout should not exceed 9mm off the center.

Here you start the gluing from the upper corner blocks up to the top block.

Finishing the corners
 (image: 3.4

Plane down the heights of all the ribs on both sides, leaving them just a little proud of the blocks. The ribs protruding at the corners can now be reduced to about 1mm from the feathered C bouts. Finish these with a abrasive paper block.

If the tips of the corners are too wide, you can reduce their length but the thickness of the C bouts at their feathered ends will also have to be reduced, because at the very ends of the corners, the thickness must still remain that of the ribs, which is about 1.2mm, not more.

Finishing the rib structure

The chapter on linings is here.

After the linings dry out, sand the whole rib structure down to the final heights, ie. 32mm at the bottom and 30 at the top /Messiah/.

Size the ends of all blocks with thin hide glue.

Removing the ribs from the mould

Before you remove the ribs from the mould, make sure it is still flat. If not, small corrections can be made with a block plane or a sandpaper on top of the workbench as used previously.

Make sure you will be able to tell the top-bottom orientation, after you have removed the ribs from the mould. Mark accordingly.

To snap the blocks free of the mould, put your thumb on the tip of the corner and tap lightly with a small hammer on the opposite side, the corner block. Repeat with other blocks, until the whole rib structure breaks free.

Category: Building