Making an ebony crown

An intricate method for a sometimes vital part of the repair process

TRADE SECRETS

Stringed instruments from the violin family can be preserved for centuries when stored and used properly by museums, collectors, owners and musicians. However, over the years various factors can cause deformations, necessitating their restoration and alteration to prolong their life.

One violin part that can be subject to wear and tear is the back button. This is the small part of the back to which the heel of the neck is glued, and which helps maintain the neck fitting position. It is rare to find well-preserved buttons on instruments from the era of the first Italian masters. Many of them are worn out, rounded off or too short, and some need an ebony crown installed. Sometimes it is necessary to replace the neck with a new one, because its length needs to be adjusted or because of excessive wear, deformation or breakage. In some of these cases, the original back button is small or short, which affects the strength and shape of the neck.

To make a button of the right size and shape, we need to fit an ebony crown. The black ebony colour creates a sharp contrast with that of the back, which contributes to the aesthetic appearance of the instrument and improves the strength of the button. These are the reasons why I use ebony crowns when I make my antiqued instruments, or when making copies. They bring the newly made instrument closer to the original model.

1a Drawing of the back button

1b

ALL PHOTOS BOGDAN BRATOEV

1 In this specific case, I am working on an instrument inspired by the iconic 1742 ‘Lord Wilton’ violin by Guarneri ‘del Gesù’. I install an ebony crown after the final completion of the heel on the neck. Using the same template, I outline the contour of the back and button (1a). I take the centre of the back as a starting point, which coincides with the centre of the button during fitting.

After that, I draw a semicircle with the help of a compass (1b). The distance from this semicircle to the edge of the button is 3mm on the right and left, and 4mm at the top. This way, I get the thickness of the crown, while the internal semicircle remains for the violin button.

2a Preparation of the ebony workpiece

2b

2c

2 I have selected in advance the ebony blank to make the crown. The preparation consists of planing a small piece of ebony (2a) with a radial section and thickness 1mm greater than that of the back button (5mm). Before I outline the crown, the dimensions of the workpiece are larger than those of the finished button, in this case 20mm (height), 26mm (width) and 6mm (thickness).

I use the same template from step 1, with which I outlined the button of the violin (2b). I repeat the outlining on the ebony detail. Using a file, I make the upper part of the crown oval and thus get closer to the size of the button. Then I find a conditional centre on the ebony detail, and draw a semicircle using a compass. It has the same radius as the semicircle I used when outlining the back button in Step 1b. I add two angled notches in the direction of the fluting channel (2c).

Cutting and shaping the back button

3 I start by cutting the back button in transverse direction with a knife, trying not to touch the heel of the neck. This will prevent damage during subsequent processing and treatment, and will create an even base when gluing. Thus the finished ebony crown will rest on the heel of the neck, fitting perfectly to it, and will look as if it is part of the back edge. I create a semicircle using a chisel and a gouge with the right curve and shape.

Finishing the button

4 Using a scraper, I finish the place where the crown will be installed, making sure that the resulting surfaces and walls are even. I need to achieve an angle of 90 degrees to ensure good contact when gluing.

Cutting the crown and initial treatment

5 I use an eclipse saw to cut the inner half-circle. Then I remove the inside of the ebony crown with a knife. Following the outlines, I gradually achieve a smooth surface, ready for the fitting of the back button.

Fitting the crown to the back button

6 The next part requires a good deal of care. I fit the crown in its place, check for small gaps, and then, using a knife, remove small shavings from it, repeating the process until the fit is perfect. Then I finish with a file to obtain a better gluing surface. I pay attention to both notches on the back, which provide additional strength and stability. At this point I also reduce the thickness of the crown so that it is almost equal to that of the back.

7a Gluing

7b

7 I use hot animal glue to attach the crown. There are two ways to tighten it. One of them involves using a clamp to hold the crown and is similar to the method for fitting the neck to the body. I prefer the second method, which utilises paper tape to help tighten the crown and hold it in place, both to the back and the heel of the neck. With the tape it is possible to tighten in all directions.

8a Final shaping

8b

8 Once the glue is completely dry, I continue shaping. First I take away material from the crown with a knife until the crown aligns with the neck. Then I continue with a file and finish with a scraper until the button is complete and the ebony crown is fitted in place. The result is an identical violin button with the same shape and dimensions as the original one (from the template). Using a file, I even out the thickness of the crown with that of the back button. I finish the process by making a chamfer on the new button.

TRANSLATION BY ROSICA DIMITROVA