This is a repeat of a first very successful commissioned instrument. It is small with a body length of only 390mm (15.4″) that is based on an 1830 Guadagnini and the record of that first build can be found here.
I visited Steffen Nowak again in Bristol to select the wood. His selection was a little limited due to Covid but still had some lovely figured sets to choose from. What I ended up with choosing was some well seasoned Bosnian maple from 2011 for the back sides and neck and some Alpine spruce from 1992 for the front.
I am keeping the design the same and the build process for #2 is recorded below:
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I decided to have a go at another cello because I enjoy building them so much! Of course I also wanted to improve on the cellos built so far by making a few judicious design changes and tweaking the build process based on experience with the earlier builds.
The key design changes were:
Sight changes to the archings (25mm belly and 23mm back)
Reduce f/b side thickness to 7.5mm from 8mm
Change break angles over the strings to improve playability (19.5 degrees ADG and 24 degrees DGC)
Changed f/b profile to match change in bridge profile
Increase over-stand by a few mm to 22mm
Attempt to increase Mode2 and Mode 5 plate frequencies to around 65Hz and 130Hz
Colouring the instrument a richer chestnut brown
The resultant design drawings done using solvespace are below.
I also decided to make use of my CNC router to build new 6mm MDF templates based on these drawings.
Build process
As usual, not everything went perfectly to plan but most of the desired changes seemed to work. The one area I had real difficulty with this time was tuning the plates especially as i was trying to hit higher resonant frequencies this time around. As I was trying to tune the top I was having real difficulty getting mode 2 and 5 and octave apart – the ring mode just didn’t want to drop. Then I happened to wash the outside of the top to get rid of some surface bruising (from when the top was drilled out) and the following morning it suddenly started to behave properly! My assumption is there must have been some latent stresses in the spruce and the wetting allowed them to settle out – a bit like annealing. Anyway I ended up with Mode 2 and 5 exactly an octave apart and matching on back and top at 60Hz and 120Hz respectively.
The finished instrument is a beautiful chestnut colour and has wonderful a rich singing tone using a set of Larsen Magnacores. I have christened her “Doris” and she weighs in at 3.01kg.
I am delighted with her – a definite keeper!
The finished instrument
The following gallery illustrates the build process.
Just finished building my first electric guitar. I can’t believe how quick that was – just 3 weeks from getting the wood to first play compared with months to build an acoustic!
Finished instrument ready to rock
I only got into this because a friend asked me to design him a travel guitar so he could take it with him while away on business. I did a bit of research and came up with a headless design that was very compact, but when I showed him the design he said he would be too scared of damaging it to take away on business! But by this time I was already hooked and had also discovered the multi-scale concept which gives the benefits of good tone on the lower longer strings, easier to bend higher shorter strings as well as better support for drop tuning due to the longer string length (and higher tension).
After a thorough investigation into available headless tuners I settled on the design offered by Nova from Brazil made from anodised aluminium and brass They offer a multi-scale 6-string bridge design which uses thrust bearings on the tuners for effortless tuning, a captive ball end design for ease of stringing up, simple to use adjustment of intonation and saddle heights and a one piece string clamp for the nut end. They are also very competitively priced (sold via e-bay). I used these tuners as the basis of a travel guitar design which I then built for myself.
The Concept
The basic parameters driving the design were:
Bottom E string length of 650mm
22 frets
Top E string length based on equal fret slopes at top and bottom of fingerboard (I ended up with 623mm)
Minimal body width allowing just enough space for controls and ensuring sufficient body stiffness
I started by getting some mahogany neck blanks and maple strips from the fabulous David Dyke down in Horam (while I was selecting some wood for my next cello).
Guitar wood
First I tapered the 75mm wide neck blank on the drum sander to give me the correct neck thicknesses plus 1mm for finishing. Then I sliced this in half and glued up the sandwich with the maple neck splice and some thin black veneer with another layer of mahogany to give the body depth.
Gluing up the neck sandwich
Then after building a simple jig to guide the small router I cut the 6mm slots for the truss rod and carbon fibre re-enforcement rods and glued in the carbon fiber rods with fish glue and seated the truss rod in some silicone grease. At the nut end I drilled a 4mm hole to give allen key access to the end of the truss rod.
Routing slots in neck
Next I glued on the guitar wings with some more maple to give some nice stripes before planing everything true and flat.
The fingerboard
The ebony blank was planed parallel to make marking the fret slots easier and I used the drum sander to get the ebony blank down close to finished thickness of 6mm and then finished with scrapers to get rid of coarse sanding marks. I built a spreadsheet to calculate the fret positions marked at the edge of the fingerboard and then joined the dots with a very fine pencil before using a jig I had made to cut the fret slots in the (flat) fingerboard.(These slots would have to be deepened later after profiling the fingerboard to it’s 16″ radius).
Cutting the fret slots in fingerboard
The Rough fingerboard outline was cut on the bandsaw before planing to final dimensions. Then I market and drilled 6mm holes to take the MOP fingerboard dots which I glued in with super-glue and then levelled off on the drum sander.
Fingerboard ready to glue on
Lastly the fingerboard was glued to the neck. I used cut off small nails hammered into the neck to mark and hold the fingerboard position and a narrow piece of masking tape to keep glue away from the truss rod.
Once the glue was dry I used a follower router bit to cut the neck flush with the fingerboard.
Fingerboard glued on and neck routed to match
The fingerboard was then sanded to a 16″ radius using a sanding block of that radius. Then I used the tenon saw with a stop to carefully cut the full width of the fret slots to the correct depth.
I chose EVO fret wire as I have used on a few other other guitars and rather like it’s look and feel. I chose 37080 which is 2mm wide and 0.9mm high. Fret wires were all tapped into place with a dab of yellow glue, bevelled with a file in a jig and the ends sealed with melted shellac. Then a quick level with a long flat diamond file and final rounding a and polishing.
The Body
I built some MDF routing templates on the CNC designed to fit round the fingerboard to give me the rough body outline which I cut on the bandsaw before routing using the templates and a follower bit.
Using my CNC router to make templates
I used the routing templates to mark the body cavities which I first rough drilled to depth on the pillar drill and then routed using the templates and a follower bit.
Controls cavity
Pickup cavities and bridge recess with maple surround
The maple ring around the bridge was cut directly on the CNC router and then glued in place inside the bridge recess.
The control cavity lid was made out of matching mahogany cut down to 4mm thick and then used an MDF template and bandsaw and sander to get a snug fit.
I drilled a hole for the jack plug and then used a long 6mm bit through that hole to drill a small hole from the control cavity through to the bridge pickup and then to the neck pickup. Another smaller hole was drilled from under the bridge to the control cavity and a piece of copper tape stuck to the bottom of the bridge recess with an earth wire soldered to it going to the control cavity. The anodising on the base of the bridge plate was sanded off to ensure a decent connection to the copper tape.
I used a thin coat of shellac to seal everything and then French polished it all before adding the fittings.
French polishing the back
French polishing top
While the French polish was hardening I did most of the pot wiring off the guitar using the template with holes for the control pots to keep everything in the correct relative positions. Then the controls were fitted into the control cavity, the pickup wires threaded and the pickup rings screwed in before final soldering of the pickup connections.
Lastly I added some locking strap buttons from Schaller to make sure I wouldn’t drop it!
The nut was cut from a 6mm bone blank and cut to give 1mm clearance from the fingerboard.
Stringing up was very easy with the Nova headless tuners. You just feed the ball end through the tuner barrel and drop into the captive recess in the brass tuner cartridge then give it a few turns before feeding the other end through the clamp and tightening the locking grub screw with an allen key. The thrust bearing means that bringing the string up to tension is effortless. The bridge height was pretty much as designed to give 1.6mm action on the top E at the 12th fret. I used a 16″ template to set the other string bridge heights. Intonation was easily achieved in a few iterations by slackening the string and adjusting the cartridge clamping allen screw.
The truss rod was adjusted to give 0.25mm relief at the 6th fret. The humbuckers were adjusted to give a 2.4mm clearance to the string when stopped at the 22nd fret.
Finished instrument
The finished instrument plays really well with fantastic access to the whole neck right up to the 22nd fret which has a really good action and good sustain even at the highest positions. The variable scale is hardly noticeable except near the nut where it does become a little awkward. The humbuckers give a great fat sound and the push pull controls (configured to single coil) coupled with the 3-way toggle give a surprising degree of control over the character of the instrument.
It is definitely travel size too – fits in a baritone Uke bag.
It is certainly easier to play standing up with a strap and if I were to build another I would certainly make some slight adjustments to the shape to make it sit better on your leg and also increase the head length so the string clamps were a little further from the nut.
Finished instrument ready to rock
Nova string clamps detail
Nova tuners detail
Top detail
Specification
Materials
Neck
Mahogany with maple neck splice with thin black edges
Fingerboard
Ebony
Body
Same as neck
Fittings
Tuners
Nova multi-scale
Pickups
Bridge: Seymour Duncan TB4 trembucker
Neck: Seymour Duncan humbucker SH-2n Jazz humbucker
Fret wire
EVO 37080
Output jack
Pure Tone multi-contact
Controls
1 volume potentiometer with push/pull neck coil split
1 tone potentiometer with push/pull bridge coil split
Following the successful build of my first parlor guitar I decided to build a second one (P02) for myself with a few design tweaks based on lessons learned from the first one.
The main changes were to:
Make the body 12mm shorter, 15mm wider at the waist, 5mm narrower at the bottom bout and 15mm wider at the upper bout
Increase the head angle to 10degrees to give a greater string break at the nut
Reduce the number of frets from 19 to 18
Create a new neck dovetail template with lightly more acute angle
Use unslotted bridge pins
Build process
Some of the key elements of the build process are captured here:
Dimensions:
Scale length
635mm
Total frets
18
Fret# at body
12
Body length
497mm
Upper bout
265mm
Waist
215mm
Lower bout
345mm
Total length
997mm
Rib depth
82-100mm
Sound hole dia
98mm
Sound hole centre from heel
153.7mm
Fingerboard width at nut
46mm
Fingerboard width at 12th fret
55.4mm
String width at bridge
54mm
Fingerboard radius
16″
Neck thickness at nut
21mm
Neck thickness at heel
25mm
Top radius
25 ‘
Back radius
15′
Top thickness
1.9-2.2mm
Back thickness
2.5mm nominal
Sides thickness
2.2mm
All-up weight
1.93kg
Woods:
Top
Alpine spruce
Back and sides
Indian rosewood
Neck
Mahogany with centre maple splice
Fingerboard
Ebony
Linings
Mahogany (laminated)
End blocks
Mahogany
Top bracing (X style)
Spruce
Back bracing
Mahogany
Cross banding
Mahogany
Bridge
Ebony. Ebony pins with abalone dots
Decorations:
Sound hole
Abalone ring
Purfling
bw+Abalone+wb
Banding
Maple
Back centre strip
Maple bounded by abalone & purfling
Neck centre strip
Maple bounded by 0.6mm black
Fingerboard dots
Abalone
Headstock
Ebony facing with inlaid crossbow
Pick guard
Tortoise shell pattern
Fittings:
Tuners
Gotoh 510 18:1
Nut & saddle
Bone
Pickup
Fishman thinline under-saddle PRO- AG1-125
Strings
D’Addario XT 56-13
Drawings
Please find below pdfs of the key design drawings:
Following on from the successful build of my second parlor guitar (P02), I decided to build a left-handed cutaway variant on the P02 body design as a gift for my son’s birthday.
Design
I chose a conventional 650mm scale length compared to the 635mm on the P02 which resulted in the bridge being pushed a bit further down the body and altered the bracing pattern slightly (as well as being reversed for the LH design). The sound hole wasn’t moved which gave room for 21 frets. I also increased the headstock angle to 12 degrees.
I was able to re-use the P02 body mould with the addition of a screw-on insert for the cutaway.
The Build
The build was basically the same process as the P01 & P02 with the exception of the cutaway which was the most tricky part requiring VERY careful bending of the rosewood. I also had to decide what decorations to do around the edges of the cutaway. I ended up putting maple edge pieces on the two cutaway side edges and continuing the abalone purfling around the cutaway on the back and front.
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.
The Design
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.
Body form
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
Sides
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.
Gluing in the top block
Gluing in the bottom block
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.
Mahogany strips ready for laminating into linings
Gluing up the linings
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.
The top
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.
Abalone rosette
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.
Gluing in the X-braces
Gluing in the maple bridge patch
Gluing in the remaining braces
Once fixed in place I scalloped the braces to give a basic profile before making some frequency measurements and comparing with the back.
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.
Back after adding the centre strip
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.
Label fitted to back before closing the box
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.
Gluing on the top
Linings notched ready for the back
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.
Gluing on the back
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.
The neck
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.
making the neck sandwich
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.
Gluing the neck lap joint
Gluing in the heel pieces
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.
Dovetail mortise cut into the body showing the hole to take the neck brace key
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.
Neck joint after dry fitting
Next I glued on the headpiece laminations with suitable cauls.
Headstock laminations being glued in place
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.
Fingerboard
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.
Neck assembly ready for gluing to body
Finally I glued the neck assembly to the body with Titebond.
The Bridge
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.
Marking the bridge position with masking tape
Gluing the bridge
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.
Intonator based on StewMac design
I also built an adjustable jig that could be clamped to the guitar top to guide the router and cut the saddle slot.
saddle slot cutting jig
Setup
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).
Finished instrument
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!
My trademark emblem – a crossbow – made from ebony, maple and abalone
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.
The mold
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.
Inner part of new cello mold
New cello mold bolted up
The ribs
I cut blocks from willow for the corners and spruce for the ends and glued into the mold before shaping with chisels and files.
Blocks glued into mold
Blocks carved to shape
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.
Gluing in the c-bout ribs
Then I could remove the outer parts of the mold to fit the linings which I mitred into the corner blocks.
Top section of mold removed to allow fitting of linings
Linings fitted
The plates
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.
Book-matched back planed flat
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. (Post build note – should be more like 4.5mm).
Then onto the lengthy process of carving the outside profile of the plates.
Rough shaping of the back with a chisel
Top after starting to rout shelf all round the edge
Back after starting to rout shelf all round the edge
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).
Plates temporarily assembled onto ribs and overhang set ready to do purfling
Then I marked the purfling channels set in 5mm from the edge and cut out using a scalpel and a fine chisel.
Purfling glued in on back plate
Purfling channel cut and faired in to back profile
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.
Back plate drilled to give rough 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.
Gluing on the bass bar
I ended up with the following mode frequencies and plate weights:
Mode 1
Mode 2 (x-mode)
Mode 5 (ring mode)
Weight
Top
26.5Hz
52.6Hz
119Hz (A3 +36cents
488g
Back
31.2Hz
63.2Hz
127.5Hz (B3 +55cents)
785g
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.
Gluing on the back
Then I removed the collapsible rib form, finished shaping the blocks and drilled the pilot hole for the endpin.
Corner and end blocks shaped and inside cleaned up ready to glue on top plate
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.
Squared up maple neck block marked up ready for cutting on bandsaw
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.
Cleaning up the rough outline of the neck
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.
Cutting the cheeks on the bandsaw
Then I sawed the scroll profile a segment at a time before using gouges and scrapers to reach the finished shape.
Sawing the scroll outline
Scroll nearly done
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.
Getting ready to glue on the neck
Neck glued on
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.
Cleaned up and ready to go in the fuming cabinet
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.
After sealing with 2 coats of shellac
After sealing with 2 coats of shellac
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.
After 1st application of artist colours
After 1st application of artist colours
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.
After 1st coat of colour varnish
After 1st coat of colour varnish
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.
After more artist colour and another coat of varnish
After some more artists colours and 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.
Gluing fingerboard back on cello #3
Then I shaped and fitted the saddle, nut and bridge before stringing up with a set of larsens.
Finished Instrument
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.
Simple jig to hold peg while drilling the string hole
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.
Simple jig to hold the bridge
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.
Scroll
Scroll
Pegbox
Side view
Back
Front
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”.
