November 2009

It occurred to me that once the top is on the violin, I will need to make a new sound post as the repair will have slightly changed the profile of the interior. There are two ways to ensure the correct length of sound post: firstly, you can guess and risk wasting precious sound-post timber, or you can measure the space and cut to size.

My book on violin repairing – which has precious little on repairing cracks! – recommends buying a sound post gauge. Luckily Atria’s book illustrates the principle quite well. And just recently I replaced the windscreen wiper blades on my car…

violin sound post gauge

You see, the spine of the old wiper blades consisted of two thin strips of mild steel about 1 mm thick and 3 mm wide and about 300mm long. I decided to get dangerous with a pair of pliers.

Once I bent the two pieces so they would nestle into each other with opposing ends (already rounded so they won’t scratch the violin timber) I found a piece of clear plastic tubing (fuel line) – although you could use a drinking straw – and bound the two strips together with the tube, and then bent the ends over so they would be easy to grasp and slide the two pieces against each other to make the measurement. I also inserted a small timber wedge from an offcut so as to provide a good friction fit that would retain the measurement while extracting the tool from the F-hole.

And here is the result – a functional sound-post gauge.

violin sound post gauge

And it works well. Happy luthiering 🙂


I ordered and received some spruce 3mm sheets – perfect for making repair cleats. There is probably enough to last me for a lifetime of violin repairs!

The extensive cracks on the violin top certainly required reinforcement. I cut a series of 5mm squares and lightly sanded them to fit the curve of the inside top plate and glued them in place along the largest cracks with hide glue. Then I shaved each of them down to a low pyramid.

This process took a couple of hours as I needed to get each one in place and clamped and set, then when the glue was set, I began shaving them down with a very sharp chisel.

Here is the result

violin repair cleats

This last one is a little different, and is known as an ‘eyebrow patch’ which involves removing some of the original timber and inserting a piece of spruce and carefully shaving it down to be flush with the surrounding wood. This makes for a strong repair, and as it is still spruce – the same as the rest of the top, there should be little impact on the sound. It is the strongest way to repair an F-hole failure.

violin repair cleats