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Started Viola #2 Commission

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.  That one was based on an 1830 Guadagnini and the record of that 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.  This what I ended up with.  Well seasoned Bosnian maple from 2011 and Alpine spruce from 1992.

I am keeping the design the same but the build process for #2 is recorded below.

 

Making Cello No.4

Design

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.

cello template da2 top

cello #4 back profile

cello #4 belly profile

fingerboard profile #4

cello #4 side view

cello #4 neck

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.

Travel multi-scale electric guitar completed

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
  • 1 trembucker TB4 bridge pickup, 1 SH-2n Jazz humbucker neck pickup
  • Minimal controls – 1 push/pull volume, 1 push/pull tone, 1 3-way toggle
  • integrated neck design for simplicity

The guitar was drawn up using the Solvespace parametric drawing package and the design pdfs are here:

travel guitar multiscale

travel guitar multiscale no dims

The Build

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

1 3-way toggle pickup selector

 

Dimensions  
Scale length Bottom E: 650mm

Top E: 623mm

Frets 22
Neck width at nut 43mm  7mm string spacing
String spread at bridge 53mm  10.6mm string spacing
Neck thickness 20mm at nut

23mm at body

Action at 12th fret 1.6mm (top E)
Overall length 756mm
Overall width 195mm
Body thickness 43mm
Fingerboard radius 16″
Weight 1.88kg

 

P02 Parlor Build

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:

Parlor P02 body template

Parlor P02 fingerboard template

Parlor P02 Headstock

Parlor P02 purfling

Parlor P02 rosette

Parlor P02 sideview

OM1 LH Cutaway build

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.

Dimensions:
Scale length 650mm
Total frets 22
Fret# at body 14
Body length 497mm
Upper bout 265mm
Waist 215mm
Lower bout 345mm
Total length 1039mm
Rib depth 82-100mm
Sound hole dia 98mm
Sound hole centre from heel 153.6mm
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 2.0-2.2mm
Back thickness 2.5mm nominal
Sides thickness 2.2mm
All-up weight  

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 Rosewood. 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 MOP
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

OM1 sideview

OM1 bridge

OM1 body template

New Workshop Completed

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:

And here is a gallery showing the construction process over the last 3 months:

 

P01 Parlor Guitar Build

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.

Dimensions:

Scale length 635mm
Total frets 19
Fret# at body 12
Body length 509mm
Upper bout 250mm
Waist 200mm
Lower bout 350mm
Total length 997mm
Rib depth 82-100mm
Sound hole dia 98mm
Sound hole centre from heel 166mm
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 1.8kg

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 Rosewood. 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 MOP
Headstock Ebony facing with inlaid crossbow
Pick guard Tortoise shell pattern

Fittings:

Tuners Gotoh 510  18:1
Nut & saddle Bone
Strings D’Addario   EXP17 (XT 56-13)

The drawings as pdfs are here:

Jigs

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

The design drawings are here:

Dovetail jig

I had the template plates for making the dovetails with a dovetail follower router bit laser cut from 6mm acrylic based on this design:

Dovetail P01

Top Solera

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.

Banding glued in place - note the white PTFE where the abalone will go

PTFE strip half removed

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.

Abalone purfling all scraped 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

Back of the neck showing the maple splice

 

Viola “Carice” finished

After 6 months of work my first viola is now finished and my client has decided to call her “Carice” after Elgar’s daughter.

It is copy of a 15.4″ Guadagnini and weighs in at just 512g (without the chinrest) 575g with a Kreddle chinrest compared with 565g for the original. 

Sounds rich and responsive (when I play it like a cello!).

See the build history here.

Finished viola body

Finished viola back

Finished viola front

 

 

 

Finished viola peg box

Finished viola side

Finished viola side

Cello build #3

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.