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Instrument Making School - Lecture 3, Making A Mould This lecture covers the procedure to make the mould (Figure 2C, Lecture 2). To complete this lecture, you will need a rectangular piece of MDF wood (wood that does not have too much grain but is stable). The piece of wood should be 400 mm long (15.75') by 250 mm in width (9.84'). It should be no more than 16 mm (0.62') thick and no less than 14 mm (0.55'). Position the inside template right in the center of the wood, make a center line on the wood and pin the inside template (using nails of 2 mm thickness, 35 mm (1.38') from each end right in the centre. You should use a 2 mm nail with the head cut off and the butt squared off. Note: for the rest of the lecture we will be using the metric system for your reference 1 mm = 0.0394" (to convert millimetres (mm) into inches divide millimetres by 25.4.To pin the wood When you position the template on the wood, make sure to clamp them together. Carefully drill the wood using a 2 mm drill bit. The nails need to fit perfectly so make sure to have a snug fit so there is no movement of the template. Once the template is pinned on the wood, using a very sharp pencil or scribe, trace the outside of the mould exactly. Then simply flip the template to the left and trace the outside of the mould exactly. Now you should have the outline of both templates on the wood and can proceed to mark and cut out inserts for blocks, there being six blocks (see photo below), procedure described below.
The following are the measurements: Top block is at the neck end, smaller bout Working of the centerline from the top edge mark out a vertical line of 15.5 mm. The line should be 49 mm in length i.e. 24.5 mm either side (see Figure 3B, note the top and bottom block measurements).Bottom block is at the large bout Working of the centerline from the bottom edge mark out a vertical line of 12.5 mm. The line should be 42 mm in length i.e. 21 mm either side (see photo below).
Lower left and right bout For the side blocks, you will need a protractor. Using a ruler make sure that the length from point to point on the protractor is 147 mm. Working from the bottom bring the protractor around from left to right and as soon as it hits the left edge, make a pencil or scribe mark (see photo 3B above). Still working the protractor around, as soon as it hits the right edge make another pencil or scribe mark. Now you can draw a horizontal line between these two points that you have marked. This procedure is repeated for the "higher" edge, but this time the length of the protractor from point to point should be 159 mm (see photo above). Once you have completed this you should have two horizontal lines as can be seen from the photo below. Now you should mark a reference point 17 mm from the lower line (see photo 3B). From this reference point simply rule a line up to the edge of the top line as can be seen from Figure 3B.Upper left and right bout The process above is repeated but with different measurements. Simply turn the mould around 180 degrees so that the measurements below can be applied to your situation. Using a ruler make sure that the length from point to point on the protractor is 126 mm. Working from the bottom bring the protractor around from left to right and as soon as it hits the left edge, make a pencil or scribe mark (see photo 3B above). Still working the protractor around, as soon as it hits the right edge make another pencil or scribe mark. Now you can draw a horizontal line between these two points that you have marked. This procedure is repeated for the "higher" edge, but this time the length of the protractor from point to point should be 140 mm. Once you have completed this you should have two horizontal lines. Now you should mark a reference point 16 mm from the lower line (see photo 3B). From this reference point simply rule a line up to the edge of the top line as can be seen from Figure 3B.You should now have your 6 blocks marked out. Proceed to cut out the violin mould that you have marked out just outside the lines with your saw. Then use a file and sandpaper until the line just disappears which will give you an accurate outline. Ensure that everything is properly square and true. As you can see from Figure 3A, there are holes strategically placed for clamping the blocks (next lecture). They should be in line with the blocks. Alternatively you can cut out a rectangle within that area, as long as you can get a clamp in there.Once everything has been cut out properly, you should sand all the pencil or scribe marks off (you can of course leave them if you wish). Once you have done that, estapol or varnish should be utilized to seal (stabilize) the wood as it is prone to buckling or changing shape. We realize that you will have many questions regarding this lecture (the procedure is quite confusing). As such, feel free to contact Mario on violinmaker@violin-world.comIf you want to skip this lecture completely, the mould can be created for you for AUD$400.00 (only $8 shipping within Australia), $16 overseas (does not qualify for sales tax exemption).
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