Making a violin - part two

By Richard Panting
Photographs Jude Woodside

Final steps to complete the instrument

Making a violin is a complex job involving around 40 pieces of wood of various types and sizes and plenty of patient, skilled woodworking. In Part One we chose the best maple for the back and spruce for the belly, shaped these plates and created the rib structure. We followed the intricate placement of the purfling decoration on the plates. Now it’s time to finish the construction, placing the bass bar on the under-side of the belly, installing the linings on the ribs which provide a structure for gluing the top and the back to and then completing the assembly. This includes the fingerboard, neck with its scroll and tuning pegs, bridge and tailpiece.

Unshaped bass bar strut in position.

Scribing bass bar.

Bass bar
The bass bar to reinforce the belly is a spruce strut about 270 mm long x 5.5 to 6 mm across, 15 mm high, placed longitudinally inside at a slight incline just inside the upper eye of the left f-hole.
Bass-bar wood grain is slightly narrower than that of the belly wood, light and with a clear bell-like sustained ring. I draw its position with the plate in the holding jig and then spot-glue the bar ends in position.
I use a washer about 30 mm in diameter and a fine pencil to roll along each side of the bar, transferring the curve of the belly to the bar. The bar is removed and I use a small plane to re-move the waste to the line. This helps the initial fitting to go faster.

Temporarily gluing scribed bass bar.

Thumb planes shape profile.

Chalk fitting
The bar has to fit precisely. Use a piece of chalk to liberally dust the surface of the marked position on the plate and gently rub the bar to and fro precisely in its place. The chalk dust is transferred to the bar where it touches; this area is carefully scraped away and the process continues until the bar fits along its length.
Be careful to hold the bar vertical, not horizontal, to the inside surface. Do not forget that the plate is upside down in the holding jig and mistakenly make and fit the bar on the wrong side (unless you want to make a right-handed violin…).
Before gluing, I draw the finished shape on the bar oversize and cut away the excess. This makes final shaping easier. Practise this tricky glue-up with a dry-run or two, clamping the centre of the bar first. The lightweight plywood clamps can exert enough sprung pressure or you can use light weight aluminium clamps. As usual fresh hot hide glue is used; this makes the accurate bar placement tricky so double-check after fitting all the clamps. Leave to dry for eight hours before cleaning up any excess glue with hot water and a brush. Use the small thumb planes and scrapers and then sandpaper to achieve the final shape and profile.

Bass bar clamped.

Clamping ribs.

Linings
To finish the rib garland prior to assembling the body, I release the spot-glued blocks from the mould with a thin palette knife and ease the rib assembly off. The remaining two stages are to bend and glue in the linings, then shape them and reduce and shape the blocks.
I separate the halves of the two-part mould and re-clamp the ribs around the bottom half. This stops the ribs moving out of shape while I bend the top linings. These are six strips of spruce 2 mm thick x 7 mm wide. They are bent on the bending iron and the C bout linings are mortised into the blocks.
I cut them a bit wider (9 mm) to allow for planing to the rib height. I remove the clamps and now clamp the top half of the mould in place while I cut the mortises and bend and fit the lower linings. Now with both sets of linings bent, I fine-fit and glue them in place, starting with the C bouts in the bottom (while the upper mould half is in place).
I use little metal lining-clamps now, but for years I did perfectly well with slightly modified, wooden clothes pegs with an extra rubber band wound around. You need quite a few of these. I leave these to dry overnight (or at least eight hours), remove the clamps and slide the ribs off the mould.
One set of linings already stiffens the rib structure remarkably and I now glue in the other set of linings. I’m careful to set them at only 7 mm be-low the rib top—minimal weight is the goal and the basic function of the linings is to increase the gluing surface of the ribs to the plates.
Using a fine-set, sharp, block-plane and file, I trim the linings flush with the ribs, careful not to remove any rib material. Then I use the knives to trim the linings to a bevelled section, taking care not to score the ribs or re-move any of the top edge.
Now I use a gouge to split away the excess wood of the corner blocks, then file them smooth and finish them and the linings with sandpaper. Use hot water and a stiff brush (sparingly) to remove any glue squeeze-out.

Body assembly
The body parts are now nearly ready for assembly. I like to semi-finish the edges of the gluing side only on the free plates. These edges have a small chamfer (about 0.75 mm) made with a fine oval file around the perimeter. I round this progressively with a file then fine sandpaper so it still has a somewhat square profile. The other edge (purfled side) is finished after the body is assembled and the corners finally cut back to shape (these were left long at the cut-out stage).
The back is glued first. I prepare a fresh batch of hide glue and lay out all the closing clamps ready. The bottom surface of the rib garland (check that you are gluing the bottom), the end and corner blocks and the top of the rib purflings are glue-sized with diluted glue (a little extra water on the brush).
I let this soak in while I carefully spread a thin line of glue just inside the pencil line on the perimeter of the plate. The more accurate the glue placement, the less to clean up later. Fresh glue is applied to the block surfaces and their corresponding part of the plate and the rib garland is positioned on the plate. Quickly clamp both ends of the body, using the alignment-pencilled margin as a guide.

Gluing lining.

Clamping lining.

Corners
T
o glue the corners, first I use a palette knife heated in the water of the glue pot to re-flow the glue between the corner surfaces, then align and clamp.
With these six clamps in place, the ribs should be pretty much sitting with the plate overhang symmetrical. I reflow the bead of glue with the hot wet palette knife and feed in some more glue, working in small sections bout by bout and clamping as I go. There is enough flexibility in the rib assembly to correct the overhang be-fore tightening each clamp.

Linings clamped to dry overnight.

Rib frame with linings trimmed flush.

Clean-up
To clean up the excess glue, I go around the outside of the clamped joint with a brush and hot water but also make sure the glue is worked into the joint. I do the same on the inside and double check the overhangs.
If something needs realigning its easy to unclamp and use the palette knife to open the joint, work in more glue and a little hot water and re-clamp. When the glue has dried overnight I remove the clamps and use a brush and hot water to remove any excess glue, inside and out. I usually go over the inside with fine paper and a sanding block. At this point I glue in my label, positioned so that it can be read through the left f-hole.
Now I follow the same procedure with the belly and complete the assembly of the body.

Edges
Before the outside edges are rounded, I need to cut the corners back to their final shape. I have to try to create equal widths across the tips. The angle of Guarneri’s corners are a little more upright than those of Stradivari as study of their violins shows. When I’m happy, I move on to the edge-work. The profile of the edge is formed by two chamfers then rounded with file and fine paper. Initially the crest of the edge should be very clearly defined as this will be softened later with fine paper.

Saddle
With the edges finished I complete the last stage of the body, making and gluing the ebony saddle at the centre of the bottom bout. The semi-finished saddle can be obtained from accessory suppliers.
The mortise is marked and cut back to the line drawn across the purfling. The depth goes through the plate entirely so that the saddle sits squarely on the block. I do the final shaping with a 10 mm gouge, oval file and fine paper. With this done, the “box” of the violin is now complete.

Trimming linings to a bevelled section.

Scroll and neck
The next steps are to carve the scroll and neck and make a fingerboard. The scroll block is a rectangular block of maple, hopefully very similar in markings to the back and rib wood. This is usually supplied oversize and there is room to square it with the grain running horizontal to the sides.
If the block is wedge-shaped, I square the top and one side then build up the other by gluing on a piece of soft wood (pine or scrap spruce) and squaring it to the top. (This is later completely cut away during the carving and shaping). A perfectly square, sectioned block makes for accurate marking on both faces.
I use a scroll-and-neck template from thin, galvanised tin sheet to mark the block carefully on both sides, checking the exact alignment. The shape of the spiral is marked with dots through the template.
I bandsaw the shape carefully. If your bandsaw cuts accurately with no deflection of the blade, your cut should look the same on both sides.
Now I use a couple of sanding drums in the drill press and a thin flat file to smooth the shape, then continue marking the dimensions and width of the pegbox using two remaining templates. All measurements and templates are referenced to a lightly scribed centre line around the perimeter of the block.
While the block is still squared I like to drill the holes for the pegs which will be fully reamed later on.

Back glued and clamped first.

Front and back glued and clamped to body.

Volute (spiral)
I cut out the pegbox sides to the beginning of the volute (spiral). I file the surfaces back to the line. Cutting out the volute follows several stages.
First I make a series of cuts around the first turn, within 1 mm of the fishtail template line. The last of these cuts stops at the throat. These cuts are duplicated on the other side.
Now I use a chisel to cut away the waste. The angles can now be smoothed out with a gouge, cutting back nearly to the pencilled dots, and further smoothed with a file.
I continue the line of the “fishtail” around the second curve and make a further series of smaller cuts as before. Again I clear away the waste with a chisel and gouge and refine the spiral, which has now emerged, with gouges and flat files. Be careful not to undercut the shape of the spiral—it should look at this stage as if two dowels traverse the head.

Cuts around the first turn.

Chisel away the waste.

Refining the cut, careful not to undercut.

Scroll identity
I refine the dimensions according to the detailed drawing and measurements on the plan. It is fascinating that scrolls can assume some sort of defining identity associated with a maker, almost like fingerprints, so experts can often identify unlabelled violins with an almost forensic accuracy. A famous violin with a replaced scroll loses a significant amount of its value.
When I’m happy with the refined shape, I use a small flat file to put a small chamfer (approximately 1.2 mm) around the edge of the scroll and the sides of the pegbox.
Two more carving steps remain. The underside of the pegbox is fluted on either side of the centre line and these two flutings continue round and over the top of the scroll profile. I’m careful to leave the centerline crisp and absolutely true. The initial hollowing is done with a narrow gouge then widened and smoothed with small elliptical scrapers followed by paper wrapped around appropriately sized dowel sticks.

Pegbox
To hollow out the pegbox, I use several drills and the drill press to remove most of the interior waste after the wall widths have been marked with the template. The pegbox walls in-crease width towards the bottom so leave the sides quite oversize.
I use chisels of varying widths to pare the remaining wood away, checking the thickness of the walls with dial gauge calipers. The bottom of the peg-box is flattened with chisels, leaving a minimum thickness of 3-4 mm.
The wood surface softened with water is easier to cut smoothly. I leave the shaping of the neck until I have prepared the fingerboard.

The profile of the edge is formed by two chamfers then rounded

Fingerboard
Fingerboard blanks are supplied over-size and need to be planed to the standard dimensions. The surface cross-profile (usually 42 mm radius), a slight lengthways concave scoop, has to be established.
I use a fine-set, very sharp, small block-plane followed by a concave scraper, to establish the correct surface with no bumps or irregularities. I then use progressively finer sandpaper with a profiled sanding block and a little mineral oil to polish it to an almost mirror finish.
Finally the underside of the finger-board has to be thinned and the cut-out lengthened somewhat. I do this with a wide gouge followed by small toothed planes, scraper and several grades of paper over a specially shaped block.
Fingerboard work would have to be my least favorite part of violin-making. The ebony dust gets everywhere—up your nose, on your face, and it’s a real nuisance to remove from fresh white violins. Nevertheless, it is a very important part of violin set-up for the comfort of the player and the optimal functioning of the violin.

Final dimensions
Now the fingerboard is spot-glued to the neck surface. Between the fingerboard and the pegbox cavity is the nut, which is grooved to locate the four equally-spaced strings. This small ebony block is squared to fit exactly to the fingerboard end and the neck surface and shaped to the curvature of the fingerboard. With it fitted and glued in place, I continue to reduce the neck with fingerboard and nut to its final dimensions and profile. When finished, the completed scroll/ neck/ fingerboard is ready to be mortised in to the body of the violin and the button shaped, then varnishing can commence.

Black saddle at the centre of the bottom bout of the body.

Cross-cutting fine bits.

Use gouges to create flutes either side of the scroll block.

Fitting the neck
This operation is one of the most criti-cal in the making of the violin. It creates the correct ratio between the neck length and the body edge to the bridge centre, often referred to as the “mensur,” a ratio of 2:3. This is standardized at 130:195 mm, measured from the front of the nut to plate edge and plate edge to centre of the bridge position. It also creates the correct upwards elevation of the fingerboard, vital to the height of the bridge and the comfortable clearance for the bow over the C bout edges. And of course the neck has to be exactly centred in the body. With the heel of the neck finished to dimension, I transfer the widths to the top and bottom of the ribs at the upper centre line and draw the outline for the mortise. The dimensions of the neck template should give the degree of slant of the heel, commonly 87º and also the appropriate total length of the neck so that the eventual mortise ex- tends a little deeper than the back of the purfling, but of course running deeper towards the button.
The height of the heel is initially too long, to allow for custom fitting; this is pared away as the cut progresses and the mortise widens accordingly. Remember, there are three  dimensions to be continually checked:
the tilt of the neck in the mortice; 
the height of the neck above the
violin top (upstand); and
the depth of the mortise, always keeping the neck centred in the body.
I aim for an upstand of 6.5-7 mm and a projected height from the top of the fingerboard at the bridge position of 27-28 mm.
This sounds like a formidable procedure but with slow patient work it turns out well. The finished dry-fit of neck to body should be tight enough to allow lifting vertically without separating. But not too tight: as always, the hot glue swells the wood. I pencil around the bottom of the heel on the button surface and remove most of the excess wood of the button, making sure to leave a good margin for final shaping.

Boring out peg box.

Scraping outside of fingerboard.

Double-check
Now it's time to double-check all measurements before gluing. It is good practice to size both the mortise and back surface of the heel with dilute glue and adjust the it again. This prevents starving the glue joint, which has to be very strong.
I now make the joint, using a single clamp with a cork-lined, shaped block on the fingerboard surface to avoid any damage and a generous amount of glue in the mortise to ensure there is good squeeze-out. Working quickly, there is time to check all the measurements one more time. I leave to dry overnight, clean up any glue squeeze-out with a brush and hot water.

Fingerboard hollowed by toothed-blade thumb plane.

Scraping inside of fingerboard.

Button
With the neck successfully glued, I finish the button. The dimensions of the button are by now largely determined by the taper of the neck heel but there is a small amount of leeway to reduce or alter these if necessary. I use a small flat file to create a chamfered edge, ideally the same width as that running around the heel of the scroll (about l.75 mm). Voila!
The body is now essentially complete and I can begin the final preparations for varnishing. I remove the fingerboard which was only lightly spot-glued on. This gives me complete access to the whole surface of the top for varnishing. I do the final clean-up of the surface, paying particular heed to the channel and edge work. Shadow lighting is essential to clearly show any defects.
I use a combination of scrapers and sandpaper to achieve the desired finish. A scraper is preferred for accentuating the surface texture, particularly on the spruce (top) where it creates a slightly “corduroy” look. A sanded surface can look plasticky and mass-produced and looses a lot of the character of the work.

Finished dry-fit of neck to body.


A fresh violin is very white indeed, so a preparatory step is to colour the wood. This makes the desired intensity of colour easier to achieve without too many coats of varnish. Water- based stains of a golden-brown hue work well under the varnish and give an “older” appearance.
A long period of exposure to UV light either from sunlight or a drying cabinet with UV tubes also colours the wood but usually I don't have the time to wait.
Water-based  stains raise  the grain of the wood and I lightly burnish the surface with old, fine sandpaper. To prevent blotchiness, especially in the spruce top, the wood needs to be sealed. I use a simple thin coat or two of dewaxed shellac and rub down again.
I make an oil varnish with Kauri gum in an old recipe originally using amber (Kauri and amber are from the same family called “copals”). Kauri characteristics are;
good drying,
long-term stability, and
hard-wearing wear without being too hard.
I also like the fact that it is a local product. The first couple of coats are without extra colour to give a nice, golden- amber-brown base layer. I brush these with a set procedure: first scroll, then ribs, back and finally belly.
A small amount of spike lavender in the varnish makes it flow and self-level. In variable weather conditions, using a drying cabinet with UV tubes wired in parallel I can reliably do a coat of varnish every 24 hours. A light rub-down removes dust particles from each coat.
One of the oldest colours added to violin varnish is made from madder root whose basic colour always contains elements of red-purple-brown. I have made my own madder lakes but commercial products  are readily available
Varnish should be as transparent as possible but a concentrated colour is needed: by the time the varnish is diluted, it rapidly becomes less intense. Five thin coats will build up the varnish to suflicient thickness and depth of colourˆall are lightly rubbed down. The finished violin hardens in the cabinet for a couple of days before I remove the dust again carefully and smooth it as little as possible - too much gives a smooth mat surface without character.
The procedure I describe is for a full coat of varnish; I don't go into “antiquing” the finish which some makers do and which takes skill and time to be convincing.

Measuring the neck.

Checking the neck position.

Wide chisel to excavate neck mortise.

White violin.

Applying colour.

Varnish first coat.

Varnishing the scroll.

UV cupboard.

Finishing
Last steps to the finished body are to permanently glue the fingerboard back on to the violin and finish the set-up: fit pegs, sound post, cut a bridge and fit the strings and chin-rest. The fingerboard and nut are glued on with a moderately light glue solution.
In the course of its life, the fingerboard has to be removed for re-surfacing every couple of years so maximum glue strength is undesirable.
Now the peg holes are reamed out to accommodate the prepared pegs. Standard reamers with the taper l:20 are used. I go slowly taking care to keep the pegs aligned horizontally and vertically square to the centre line of the violin. The shafts protrude about l2 mm to the collars on the peg heads and the extra length is cut off and the ends rounded and smoothed. Peg paste is rubbed in on the bearing surface of the shafts and holed are drilled for the strings.

Applying varnish.

Peg holes are reamed out.

Sound post
The sound post is now fitted. It sits about 2 mm behind the right bridge foot, inside it, and in line with the “ankle” of the foot. This is a good starting point but is adjusted to find the most resonant response from the violin. The ends are trimmed the exact angle of the inside top and bottom and the length adjusted to a moderately firm fit
Before the bridge and sound post are fitted, the end button-hole is reamed with the peg reamer (same taper) to accept the button as an easy push-fit. The tail gut (these days mostly a nylon loop secured and adjusted by small brass nuts) is fitted to the chosen tail- piece, as is a fine tuner for the E string. The oversized bridge blank has to be reduced to the desired dimensions. The feet have to fit the curvature of the belly exactly, the thicknesses have to be reduced and the various cut-outs adjusted. The top of the blank has to be appropriately curved to give comfortable clearance between adjacent strings and cut for the right height of the equally spaced strings above the fingerboard. 
Sound post and bridge fitting are complex operations that require familiarity and experience for an optimum tonal result.
Usually I use old strings while setting the bridge and making final adjustments to allow the violin to settle for a few days before fitting a new set. Finally, the chin rest is Fitted and a final polish given to the body and all is ready for a trial playing session.
There are many stages in making a violin and within the scope of a two-part magazine article, it is not possible to give the most complete account. Those keen to make their own violin can consult the books and extra sources listed with this article.

Sound post inserted through f-hole.

Paper gauge for fitting bridge above sound post.

New Zealand woods
How suitable are New Zealand woods for instrument making?
I  have never used these, but have been told that southern beech and mangaeo have been used as satisfactory substitutes for maple. I have seen and heard a cello made in Taranaki in the 1920s using flamed mangaeo with a kauri belly and it sounded very well.
But i haven’t heard of any other makers using kauri in stringed instruments.
One characteristic that is decidedly different is the appearance— few woods exhibit the degree of distinctive flames that maple does. Both spruce (picea abies), in addition to its very regular growth  rings, and maple often have a distinctive and attractive pattern of medullary rays, the sap channels that show when the wood is quarter-cut.

Varnishes
Despite the myths that the fabulous tone of violins by Stradivari and other classical makers come from the almost-alchemical properties of the varnish, the facts are more prosaic.
Violin varnish is either an oil or spirit type. Early recipes, as far back as the 12th century, were almost all simple combinations of resin and a drying oil (walnut, then later linseed) cooked and diluted with a solvent which was usually vegetable turpentine or an essential volatile oil such as spike lavender.
Dyes and pigments were added. the resins were tapped as sap from coniferous trees such as pine, spruce, larch. A more expensive material was amber, a fossilised resin which required special preparation.
Spirit varnishes use an alcohol to dissolve the resin, with colourants and some oils added as a plasticiser. Their main advantage is their quick drying-time and relative ease of application, which suited to the emerging market for mass- produced instruments in the 1800s. The invention of dyes from coal tar in the mid-1800s increased their versatility.

Richard Panting.

Clarification
In part one of this violin-making article, the statement “the more mature the wood the better” needs clarification. that does not always hold.
Recent research (dendrochronology) has shown a number of the famous violins of Guarneri, Stradivari and others were made of wood that was barely seasoned (dry). We are talking just a few years against the 15-plus years of wood maturity that makers today like to use.
Equally, the assertion “the denser the wood the greater its response for sound” needs qualification. Most makers today prefer wood that is, all other factors considered, of only medium density. Weight can reduce the quick response to vibrations that is a very desirable feature of any string instrument.

Recommended reading
Simone F  Sacconi, the “secrets” of stradivari (libreria del convegno, cremona, 1979) Henry A. Strobel, Violin making step by step (Henry Strobel, violin maker & publisher © 1994, 1995, 1996 1997, Oregon, USA), and others in the Strobel series for violinmakers Chris Johnson and Roy Courtnall, The art of violin making (Robert Hale, London, 1999)