I recently received a commission to build another viola from someone who very much liked the 1st one I made and wanted one like it. This is a small instrument with a body length of only 390mm (15.4″) that is based on an 1830 Guadagnini and the record of the 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.
Here are some pictures of the finished instrument which weighs in at 522g (without chinrest):
Viola #2 frontViola #2 backViola #2 side view
I am keeping the design the same but the build process for #2 is recorded below:
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.
