The humble wedge is a stalwart of the luthier’s workshop. Joseph Campanella Cleary examines some of the myriad ways they improve the quality of life for craftspeople

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Offcuts from wedges create more wedges. Keeping a variety of wedges handy gives the luthier a flexible way to solve various work-holding problems © Joseph Campanella Cleary

In a world of technological progress, the violin maker’s workshop is an oasis of simplicity and elegance. Among the tools that connect the luthier’s work to antiquity is the wedge, one of six ‘simple machines’ that can exert pressure from feather-light to crushing, in the service of repair, restoration and making new violin-family instruments. 

Sometimes the wedge is the tool, for example a knife, plane iron, chisel or gouge. The angle of the blade determines the use and application of force. The smaller angle of a well-sharpened knife gives the luthier control over cutting a chamfer or shaping an edge – the tool cleaves the wood easily with a low input force. A larger angle, like that of the stout-bladed froe, requires a correspondingly larger application of force, which is delivered with a mallet or beater, dividing the wood along the weakest plane perpendicular to the growth rings. Other ‘wedges as tools’ serve to hold the work, especially when the wood is not yet flat, square or perfectly dimensional. A properly shaped wedge is often the least complex solution to difficult problems. Making one wedge often yields another of a smaller but related dimension, which can be kept for later use. A compound wedge expands usability by covering two distance ranges, and it can be used in a variety of contexts. 

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The cast-iron froe is a toole used for splitting tonewood from rounds. This allows the luthier to allign the plane of the top and back with the natural plane of weakness of the tree © Bruce Harvie/Orcas Island Tonewoods

Wedge-based solutions for luthiers start at the tree. The best tonewood comes from trees that have grown without twist, from rounds that are split with wedges, and further divided using a froe (especially for spruce). Working ‘with the split’ is desirable for every part of the violin. The wedge-shaped billets of maple and spruce must be (a) supported and planed true on a work bench, and (b) have an edge planed square, in order to form the centre joint. 

Two specialised wedges can help with these operations. The first is slightly shorter than the top or back, with bevelled ends, so it can be inserted at an angle if needed. It supports the work so that it doesn’t flex under the plane. Without proper support, the wood may flex to meet the workbench, and may end up hollow or crowned. For the centre joint, some luthiers clamp the jointer plane, and push the plate over it, but I prefer to clamp the work in a vice in order to observe the shaving as it comes out of the throat of the plane. With a slightly crowned plane iron, I can correct for squareness, by adjusting my line while also planing true, end to end. A full-length ‘flexible’ wedge holds the flat face of the plate against the vice jaw without allowing distortion. The wedge is made of two pieces of light pine, joined with leather and shaped to a generalised profile. It adapts to the negative space between the top of the plate and the vice jaw, keeping the plate flat so that the edge may be planed. Overclamping is unlikely, since the vice only need exert enough force to overcome that produced by the jointer plane. This force is further reduced by a freshly honed blade, set lightly to take tissue-thin cuts. 

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An ebony wedge with .5mm height graduations is used for tool set-up © Joseph Campanella Cleary

But sometimes the wedge is the part. The function of violin tuning pegs depends on their conical wedge shape. There are also wedges in the bow, holding the hair in the mortise(s), and careful insertion of a ‘spreader wedge’, under the ferrule of the frog, is responsible for maintaining the full width of the horsehair ribbon. 

Both the bridge and the fingerboard are unusually dimensioned parts, for which wedge-based solutions are useful. The ebony fingerboard can be securely held for planing in a double-sided jig. One side is deeper, and relieved to accommodate the radius, allowing the gluing surface to be planed. The other side is shallow, for planing the top, radius and scoop. The fixture is comfortable to hold, supporting it against a bench, or it can be clamped with bench dogs. For gluing fingerboards on new necks, I align and clamp the board, and then spot-glue several small cleats on each side. I enjoy the predictability that is gained during the gluing, as the board wedges fit perfectly into place before clamping.

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Bench wedges level and support a billet so that it can be securely clamped on bench dogs without flexing © Joseph Campanella Cleary

Another wedge-shaped planing aid is a small bench hook for violin bridges. Low, tapered willow rails hold the bridge securely for planing to thickness and several other cuts. Of course, it is possible to shape and plane bridges without such a jig, but I have found that using one increases the comfort of doing so. 

Wedges are also commonly used in repair work. In certain circumstances, for example, a violin with a thin neck and low overstand/projection, a matching slip of maple may be glued to the neck, and planed to a taper to correct both issues. A softwood or cork wedge can be used to make a simple repair on the wing of the f-hole. Sharon Que has illustrated a more controlled method (Trade Secrets, April 2014), which uses the wedge to lift the wing back into position gently, bearing on a prepared platform, while the crack is closed with a brass clamp. In The Strad ’s November 2001 issue, Andreas Hudelmayer illustrated an elegant method for closing cracks using a wedge between ‘pillar cleats’ to direct force to the opposite side of the plate. Both of these examples increase the predictability and ultimate success of the task via the gentle force exerted by the wedge. Eliminating guesswork or alignment while gluing increases the quality of the result, and also reduces stress on the repairperson. 

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Flexible wedge for edge jointing. When clamped, the two-part wedge flexes instead of the work © Joseph Campanella Cleary

Finally, when the oppressive heat of summer is over, cool, dry air allows workshop doors to be opened. This simple machine, in the form of the doorstop, serves its humblest function for the luthier – keeping the door open to a passing breeze.

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Lining stock for larger instruments can be extended with a carefully fitted and glued, wedge-shaped ‘bird’s beak’ joint © Joseph Campanella Cleary