I finished building my new workshop a few weeks ago – something I decided to start building to get me out of my super-cramped garage as soon as the Covid-19 lockdown was announced back in March.
I went for a simple wooden framed design on a concrete base with a flat roof to give me as much headroom as possible whilst staying within the 2.5m permitted development limits on height. Plenty of rockwool insulation in the walls and ceiling and a few inches of celotex on the floor should keep things toastie in winter as well as keeping the machine tool noise inside. I clad it in Siberian larch feather-board for a good and long lasting look.
I now finally have room to swing a cat while making musical instruments (or anything else) although there is still quite a lot of stuff still left in the garage! Here are some pictures of the finished workshop:
I have just finished a new project to build a small steel string guitar (Parlor guitar). This is mainly because I hadn’t built a steel string before and also because I have a friend who may be interested.
I looked at a variety of commercial designs and listened to lots of demos before arriving at an outline specification. The main thing that appears to affect tone quality is scale length so I chose towards the longer end of the spectrum whilst keeping the 12th fret at the body for a compact design. Body shape was arrived at using a parametric drawing package (solvespace) until I got something that looked right and was neither too large nor too small.
I started by cutting a body template from 4mm clear polystyrene sheet which I finished on the vertical oscillating sander and then drilled to show positions of the sound hole and braces.
I decided to build a body form with expanding clamps inside to hold the sides built up from several (4) layers of 12mm plywood. I rough cut a template on the bandsaw and finished on the vertical oscillating sander. Then I used this piece with a router follower cutter to make the other 7 pieces which were then glued together, finished on the vertical sander and sealed.
Finally I drilled dowel holes between the two mating halves and tied it all together with some latch style toggle fasteners. To increase the stiffness I epoxied in a length of carbon fibre rod to a routed out slot on each long edge.
I then marked out the inner cauls and built them in a similar way, facing them with 3mm cork and connecting to some turnbuckles to make expanding clamps.
Side bending jig
I already have a jig for sidebending from making classical guitars so all I needed to do was build the body mould part for the new design. I cut out the two sides from 12mm plywood and connected these with 10 lengths of 15mm aluminium tubing glued into mating holes with epoxy.
Neck joint dovetail jig
After reviewing commercially available jigs I decided to design my own 2 part jig:
a lower part for securing a guitar body (or neck) at a controllable angle so that this could be worked on separately for example when working on the end splice.
The dovetail template table that can be slotted onto and then bolted to the lower part ready for cutting the dovetail male and female halves
I decided to make the top slightly domed at the lower bout and so built a solera from 25mm plywood that I built up with basswood on the lower bout and then shaped to give me a 25′ radius concavity. I also domed the top bout slightly to give me 0.8mm of dome at the top of the sound hole to match the designed angle on the fingerboard.
Building the guitar
First I thicknessed the sides (indian rosewood) to 2.2mm on the drum sander. Then I used my old bending jig with a thermostatically controlled heated silicon blanket at 120C to bend each one after moistening and wrapping in greaseproof paper.
After bending I cut to length and marked and cut the side profile with a saw before clamping into the body form.
I then cut and shaped the top and bottom blocks and glued into place.
Next I trued up the edges of the top and bottom edges of the sides by using 2 large radiused sanding blocks until the desired side depth had been reached at the two end blocks.
For the linings I used the bandsaw and drum sander to make mahogany strips for laminating before glueing and clamping (with string) to a former made of 18mm mdf.
Once dry I shaped the linings on my router table (laminate trimmer mounted upside down on a plywood base board) before gluing into place onto the sides. Once dry the excess linings were planed flush with the sides and then finished with the radiused sanding blocks.
I then removed the inside clamps in order to clean up the insides with scrapers before sealing with shellac.
I temporarily removed from the side mold in order to cut the V-shaped slot for the back strip which I made from 2 pieces of maple binding. This will be fitted after I have attached the bindings.
I first planed the edges of the book matched pieces of spruce for the top to give a perfect fit and glued up before using the drum sander to a graduated thickness of 2.0-2.2mm.
Then I fixed to a workboard and used the router to cut a 1.8mm groove in the top to take the abalone pieces that make up the rosette ring. This was first sealed with shellac to prevent the super-glue from discoloring the top. Once the abalone was in I secured with thin super-glue before routing a 1.2mm channel either side to take two strips of 0.3mm black veneer sandwiching a 0.6mm strip of maple which were then fixed with thin super glue.
Finally This was planed and sanded flat before routing out the sound hole.
The top could then be turned over and taped to the solera ready for fitting the braces and the 3mm maple bridge patch after marking their positions from the template made earlier.
Once fixed in place I scalloped the braces to give a basic profile before making some frequency measurements and comparing with the back.
The book-matched indian rosewood was first planed to give a perfect fit before gluing together and thicknessing to 2.5mm on the drum sander. I routed a 6mm channel (using a guide-rail with my laminate router) to take the maple centre strip which was glued in place and sanded flush before routing 2.6mm channels either side to take the abalone strips and purfling. Once dry this was flattened on the drum sander before turning the back over and taping to my back building board which has a 15′ radius on it to match the desired dishing on the back.
First I made up the mahogany cross grained banding strip 3mm thick and glued in place. Once dry this was sanded to it’s final rounded profile using a profiled sanding block. Then I shaped the cross braces on a profiled sanding block to give a matching 15′ radius and planed/sanded them to their pointed profile before gluing in place. Once dry these were scalloped using a chisel before making some resonant frequency measurements and comparing with the top plate. Once adjusted the back was cleaned up with scrapers and the label attached.
Tuning the plates
I used the same setup I have used for Cellos and violins but the process did not seem so clear to me as there were so many resonant frequencies and the back mostly resonated in bar modes with lateral node lines. In the end I thinned the top braces to the point where there seemed to be plenty of free resonances in the top.
I ended up with these resonant frequencies:
Back: 102Hz (G2), 199Hz (G3), 269Hz (C4), 302Hz (D4 and also tap tone)
Front: 143Hz (C#3), 183Hz (F3 and also tap tone), 231Hz (A3)
Assembling the box
I started by fixing the top to the sides whilst the sides were still contained in the side mold. I marked the position of the X-braces on the linings and cut recesses in the linings to match. Once it was all fitting snugly I glued and clamped it up.
Before fitting the back I cleaned up the glue joints on the top and gave the inside of the top a coat of shellac. Then I removed the side moulds and marked the position of the back cross braces on the sides and notched out recesses in the linings to match. Again, once it was all fitting snugly it was glued and clamped up.
Purfling and banding
I used my laminate trimmer on my purfling cutting jig with a 3mm down-cut router bit to cut first the banding and then the purfling channels. As I am using abalone in the purfling I first sourced some 2mm PTFE sheet and band sawed into 2mm high strips that could be sandwiched between the black/white purfling strips. This sandwich was first glued into the purling channel fastening with masking tape before bending the banding strips to shape and gluing into the banding channel again fastening with masking tape.
When dry, the PTFE strips were extracted and then the abalone strip (actually lots of short pieces on a very thin plastic backing strip) pressed down into the open channel left by the PTFE before flooding with thin super glue and leaving to dry. The last stage was to plane and scrape everything flush.
I started by truing up the mahogany blank before slicing in half and fitting in a centre maple splice (made from a used cello neck blank) sandwiched between two pieces of black veneer.
Then I tapered the blank on the drum sander before cutting the neck lap joint and gluing back together. Finally I added a few short pieces that will form the heel.
Next I routed a 7/32″ groove down the centre of the neck ready to take the double neck truss rod and opened the slot with files until the truss rod was a nice tight fit.
The Neck dovetail
This joint had been worrying me for sometime but I finally took the plunge. I started by ensuring the top end of the guitar was totally flat and square before cutting the dovetail mortise on the jig I had built.
I then rough cut the neck profile on the bandsaw before routing out the dovetail neck tenon on the jig I had built earlier. Then I put the body upside down on the jig to set the neck angle so that the neck projection gave me about 2.4mm clearance at the bridge position. With the angle set I proceeded to carefully cut the neck dovetail tenon so that the fingerboard was still a bit proud of the body. I then used files and chalk to fettle the joint until it was a snug fit with the fingerboard flush with the body.
Next I glued on the headpiece laminations with suitable cauls.
Once dry I marked out the headstock shape and rough cut on the bandsaw before using the laminate router and a fingerboard template made from perspex to get the final shape and as a guide for drilling the tuner holes with the pillar drill. Then I moved onto routing out the headstock decorations and rough carving the heel.
I started with a nice ebony blank that I first thicknessed to a little over 6mm on the drum sander and planed square ready for marking and cutting the frets for the 635mm scale length. The frets were cut by hand on my fret cutting jig before bandsawing the rough shape and then using the laminate router with a perspex fingerboard template I made which was also drilled for the locating dowels.
I used the same template to mark out and drill the neck before rough fitting the neck assembly to the body to check what material needed removing from the underside of the fingerboard over the guitar body. Once I had scraped that area to give a good fit I glued the fingerboard in place on the neck. When dry I used the laminate router with a follower bit to trim the neck flush with the fingerboard and finished carving the heel and headstock. The last job on the heel was to fit a rosewood heel cap.
Then I used a concave sanding block with a 16″ radius to give the correct profile on the face of the fingerboard and marked and drilled the 6mm holes for the fingerboard dots which I each secured with a drop of superglue leaving them slightly proud ready for cutting back flush.
Then I re-cut the fret slots to the proper depth, used a V-file to open up the top of the slots and then fitted the frets with a touch of Titebond. Once fitted, I trimmed them, filed the edges at a chamfer and filled the exposed slots with hot black shellac before final sanding and french polishing the neck and linseed oiling the fingerboard.
Finally I glued the neck assembly to the body with Titebond.
I cut the bridge from a rosewood blank to my own design with bandsaw and files. I designed it to take a 3.2mm saddle with a Fishman undersaddle pickup (PRO-AG1-125). The bridge pins are set back about 13mm and kept parallel with the saddle for consistent pressure on the saddle/pickup with an approx 20 degree string break over the saddle. The top of the saddle was radiused to match the fingerboard. I discovered that there are 2 standard sizes of bridge pins with a 5 degree taper (Martin) and a 3 degree taper. The reamers I used for violin pegs have a 1:30 taper which is about 1.9 degrees. Sods law had it that the bridge pins with abalone tops I had sourced from Planet Waves had a 3 degree taper while the chinese reamer I had bought was of course 5 degrees so I had to order a new one. Unbelievably I couldn’t find any in the UK and had to order one from the USA! – such is the state of UK industry!
Once shaped I sanded the underside concave to match the 25′ radius of the top before giving a couple of coats of finishing oil and polishing with fine wire wool. I positioned the finished bridge carefully on the top using a template and marked the position with masking tape before scraping away the finish to give a gluing surface. Then I glued up using special bridge clamps and a made up caul ti fit under the bridge plate inside the guitar.
To mark the position of the saddle correctly I made up an intonator jig (copied from the StewMac design) using rosewood and 2mm brass rod with 3mm and 4mm tubing sleeves that would allow me to record the correct saddle position on each string on a fully strung up instrument.
I also built an adjustable jig that could be clamped to the guitar top to guide the router and cut the saddle slot.
Before stringing up I levelled and polished the frets using diamond fret files and emery paper. The instrument was then strung up using 13-56 phosphor bronze strings from D’Addario (EXP 17 which have been discontinued but you can get the same now called XT 13-56) using the intonator jig and once adjusted for tuning I marked the position saddle position for each string before carefully cutting the saddle slot with a router and the saddle slot cutting jig shown above and then cutting a 1/8″ bone saddle blank with the correct string positions. I then drilled a small hole at one end of the saddle slot to take the Fishman under-saddle pickup (PRO-AG1-125) wire and once fitted I soldered up the jack socket and fitted to the hole drilled in the bottom block and used a clip stuck to the linings to stop the wire flapping round inside the guitar. The neck relief was set to 0.25mm at the 6th fret and the action at the 12th fret to about 1.5mm (top) and 2mm (bottom).
The finished instrument weighs 1.8kg, has a big tight sound for such a small body, has great sustain, is very well balanced and easy to play and also works very well with an amp. The friend who had first refusal is absolutely delighted with it and is selling his Martin HD28 to make way for his new acquisition!
Having just retired I recently started my 3rd cello build. I think this is going to be a real pleasure as I no longer need to burn the candle at both ends to find time for the luthiery.
I started by building a new mold that I can leave in place whlle rough fitting the back and belly to enable the overhang on the edges to be set really accurately. It is designed so that it can be taken out easily after the linings have been fitted.
I cut blocks from willow for the corners and spruce for the ends and glued into the mold before shaping with chisels and files.
Then I scraped the ribs and sanded down to 1.4mm on the drum sander before cutting to size, bending and glueing to the blocks.
Then I could remove the outer parts of the mold to fit the linings which I mitred into the corner blocks.
I had some lovely pieces of book-matched spruce and maple from David Dyke which I cleaned up and carefully planed the edge square and true. This takes a lot of time (for me) to ensure an absolutely perfect fit ready for the rubbed joints. Once dry I then flattened the back surface with the jack plane.
Then I used the rib assembly to mark out the outline on each plate allowing 3mm of overhang (using a pencil and washer) before cutting out on the bandsaw.
Then onto the lengthy process of carving the outside profile of the plates.
Once the plates outer profile had been carved to match the templates I assembled the plates onto the ribs (with the form still in place) and then used a file with a 3mm wood off-cut attached to file the overhangs to an exact 3mm all round and also set the final rib thicknesses (5.2mm on the back and 5.6mm on the belly).
Then I marked the purfling channels set in 5mm from the edge and cut out using a scalpel and a fine chisel.
Next I dismantled the back and front plates from the rib assembly ready to carve out the inside profiles.
To make this quicker I first drilled holes to a depth a few mm shy of the finished thicknesses.
Then a lot of elbow grease with first gouges and then thumb planes to get to the starting profile where I start exciting the plates with a loudspeaker coupled to a variable frequency oscillator.
It turned out that the spruce for top had a very low transversal thickness making it very difficult to maintain the x-mode frequency. I ended up having to fix a patch using some wood from a good stiff guitar top to bolster the transversal stiffness and even after that I had to accept an x-mode frequency more than an octave below the ring mode. This meant trying to keep the back’s ring mode about a semitone higher.
Final tuning was done after cutting the f-holes and fitting the bass bar to the top.
I ended up with the following mode frequencies and plate weights:
Mode 2 (x-mode)
Mode 5 (ring mode)
119Hz (A3 +36cents
127.5Hz (B3 +55cents)
Assembling the box
I started by roughly trimming the ends of the blocks before gluing the back on carefully. This was much easier with the rib form still in place.
Then I removed the collapsible rib form, finished shaping the blocks and drilled the pilot hole for the endpin.
Finally I glued on the top plate which fitted pretty well.
The neck & fingerboard
Firstly I planed and scraped the fingerboard blank to size and set the string relief to half the diameter of the strings.
For the neck, I started by squaring up the maple blank and carefully marking the outline in pencil. I had previously made a template from perspex to make this easier – particularly for the scroll where I marked through guide holes with a pin.
Then I used the bandsaw to cut out the outline shape and a handsaw to cut down the neck which I then trued up with rasps and files.
While the scroll was still a square block I drilled the pilot holes for the pegs and then cut the scroll-box cheeks with the bandsaw.
Then I sawed the scroll profile a segment at a time before using gouges and scrapers to reach the finished shape.
Assembling the box
Before shaping the heel I temporarily glued on the fingerboard and fitted the neck joint using chalk and going slowly so that I achieved:
A fingerboard projection at the bridge of 83mm
An up-stand of 23mm
A neck stop of 280mm
This is probably the trickiest bit and absolutely key to playability so worth spending the time to get it right.
Having fitted the neck joint I than shaped the heel and neck with rasps, files and sandpaper before gluing up the neck joint.
Then I trimmed up the heel, cleaned up any surplus glue and sanded down the whole instrument with 600 grade emery paper. Then I wetted the whole instrument to raise the grain and sanded again ready for finishing.
I started by darkening the instrument with a few days in the fume cupboard with a bowl of ammonia and then sealed with a few coats of shellac, rubbed down with 600 grade and then a final shellac coat.
Then I mixed some artist paints (2 parts burnt sienna, 1 part burnt umber and 1 part alizarin crimson) with a few drops of linseed oil and rubbed in evenly with a rag.
Following drying in the UV cabinet the colour was way too light so I repeated the exercise and then gave it its first coat of colour varnish. The back is looking particularly pleasing.
The colour is still a bit on the light side so I gave it another coat of artists colours with more burnt umber and less red and then another coat of varnish.
Then I left it in the UV cabinet for 2 weeks before cutting back, polishing and finishing with a wiped on coat of linseed oil.
Then I re-fitted the fingerboard and finished the neck with a couple of thin coats of linseed oil and burnt sienna artists colours burnished to a good shine.
Then I shaped and fitted the saddle, nut and bridge before stringing up with a set of larsens.
The finished instrument weighs in at 2940g, sounds wonderful
Now the instrument is basically finished it is time to set it up and hear how it sounds.
Fitting the Violin pegs
Having already shaved down the pegs to match the taper on my peg-hole reamer, I smoothed them with 600 grade emery paper and gave a light wipe-on coat of finishing oil and then burnished with wire wool.
The peg-holes were then reamed out carefully so the distance from the peg-box to thumb-piece was 16 mm. In order hold the pegs I built a simple jig to hold them while they were drilled with a 1.3 mm bit for the string holes and then lightly chamfered the edges of the holes.
The outside of the peg was marked where it protruded from the peg box and I carefully sawed off the excess using the same jig to hold the peg. Finally I rounded the end with files and 600 grade emery paper.
Fitting the Violin Nut
The Evah Pirazzi medium gauge violin strings I am fitting have diameters of 0.8, 0.66, 0.66, 0.21 mm
So to have string height above fingerboard of 0.5, 0.45, 0.4, 0.35 mm and slots 1/3 of diameter of string the nut height should be:
0.76, 0.67, 0.62, 0.42 mm
I marked the ebony nut against the end of the fingerboard and then filed down to give a 1 mm step and faired in nicely to the sides and entry to the peg-box. Once smoothed with 600 grade and wire wool the nut was lightly glued to the end of the fingerboard. I adjusted the step from 0.8 to 0.5 mm before marking the string positions using a sharp knife. I set the strings with 5.5 mm between centres and the E string 8 mm from the centre line. This gives slightly more room for the E string than the G . The knife marks were then widened first with a triangular file and then with nut files.
The last step was to file the top of the nut down so that the slots only held 1/3 string and then finished with emery paper and wire wool.
Fitting the Violin Bridge
Starting with an Aubert Miracourt blank I followed the fitting guidelines in this very good article on how to fit a bridge by Lars Kismer. I built a simple jig to hold the bridge perpendicular to the top.
Fingerboard projections were marked on the bridge and action marked at 2.5 mm on the E string up to 5 mm on the G string and joined with a curve of 41mm radius. I purchased a banjo head made of goat’s skin on e-bay which provides perfect parchment material for reinforcing the E-String notch.
Setting the After String Length (ASL)
The violin tailpiece gut was adjusted to make the ASL approx 1/6 of the string length and then fine-tuned so that the after string tuning on the G string was an octave and a fifth below the D string.
The finished violin (without chin-rest) weighs in at 420 g.
Fitting the Violin chin-rest
I settled on a Kreddle chinrest as the client specifically wanted something high. The Kreddle provides plenty of adjustment flexibility in this regard and came highly recommended. I also found it extremely easy to fit and adjust.
On first play of the finished violin, the G and D strings have a lovely rich sound and the E is strong and sweet but the A ran out of steam a bit at F. Opening up the heart on the bridge a little and tuning the B0 resonance to the A0 body resonance by putting a small piece of Plasticine under the end of the fingerboard made a big improvement.
Delivered to my client yesterday at Orchestra who was delighted with it – brilliant timing too as we had the fabulous violinist Sarah Sew working with us on the Elgar violin concerto and she was kind enough to give it a workout. Her verdict : ” it works – I mean it really works and powerful too”. Sarah also said it compared very favourably to many new build professional instruments (she tries out a lot of them) but found it a little on the “chunky” side compared to her wonderful Italian Gagliano – so not really a surprise as that is actually quite a small instrument. Clearly I will have to work on making my next violin a bit “finer”.
My good friend, recording engineer and cellist George Shilling was recently involved with Tony Iommi’s latest creative work with the Birmingham Gospel Choir called “How good it is” where George and Anna provided the cello accompaniment.
Birmingham post article complete with video is here
I just got back from an exciting afternoon with my good friend George Shilling at his Bank Cottage recording studio in the Cotswolds. George kindly spent some time recording my new cello “Anna” (after a visit to the pub).
You can find the resulting pictures and recordings here.