Tuesday, January 30, 2007

THE HEEL BLOCK

STACKING THE HEEL.

At the weekend I got around to glue the block together. As with the neck I discovered that I had been as tight with my heelblock segments as I was with my neck. I was barely able to make them fit within the patterns - it was with in millimeters. Not good! In future I must make an effort to be a little more generous when I rough cut.

As preparation for the heel I planed the first and second segments down to 18mm. This will, I hope, end up giving me even sized segments all the way down to the heelcap that is intended to align with the binding. If all goes to plan, I would just have to shave the very bottom of the third segment to accommodate for this.

Once all the segments were prepped, I carefully went about the assembly with a dry run before adding glue. I prepared stop blocks and supports to keep the segments from sliding in the wet glue, as I did when I glued the scarf joint.

Then it was time for the real thing.


HEEL BLOCK SEGMENTS

THE STACKED HEEL

CHECKING PATTERNS

THE OBLIGATORY GLUING

Saturday, January 27, 2007

GLUING HEAD VENEER

Yesterday, I prepared the neck for receiving the headstock veneer. I scraped the joint free from squeezed out glue and trued it. I must say that the Cumpiano clamping method for gluing the neck joint worked very well and as a result there was virtually no movement in it.

The top face veneer is scrap from the bridge/fingerboard stock. The end of the lumber had a 4" long check on one side of the face that rendered it useless so I cut it off 7" down used the good side for the bridge and the bad was resawn into 1/8" sliced that was just wide enough to be bookmatched into a faceplate. The check was filled with epoxy mixed with sawdust from the resawing. After the two pieces were glued together to a faceplate, I scraped it down to 2mm thickness. The other two veneer slices that make up the sandwich are maple and wenge that was cut from sheets I already had.

I also made an acrylic template for the head and traced the outline onto the faceplate.

FACE VENEERS

The veneers were then carefully laid in place on the head in position and two holes outside the template was drilled through the veneer and into the headstock. These holes were to received two small brads in order to hold veneers in place and not slide around in the wet glue when clamping pressure was applied. I also cut a clamping caul from MDF with holes to house the brads protruding from the head and veneer assembly.

READY FOR CLAMPING

THE GLUE-UP

I got a lot of squeezed out glue as usual. This time I made an attempt to wipe it off, but not very successfully. It smudged everywhere. What to do?

Wednesday, January 24, 2007

STARTING THE NECK


DISASTER!


Things didn't go to well last night. I started cutting up my neck blank and left the scarf joint cut to last - not a good idea. When I finally got to do it, my saw wandered and left an uneven cut. I blame the saw. I think the teeth has to be reset. A bad workman always blames his tools.... This would normally not be to much of a problem as the joint faces is trued with a block plane but, doing so, I was running out of excess neck stock fast. On top of that, I realized that the cut ended up being at a 17º angle rather than the 15º I was aiming for, making matters worse. 15º is already on the steep side for a classical guitar and 17º is definitely the limit. The joint will be under increased stress from the string tension and the glue surface is left smaller. I was barely able get the thing straightened and had 1mm of excess neck left when I was done, but I'm stuck with a 17º neck joint!

I should have taken some photographs of the joint faces before I started to plane them, but I was panicking and forgot .

Then things took a turn for the worse. As I was preparing to glue the joint, I couldn't help noticing that the whole neck looked a bit wide, but didn't think much of it. I cut my clamping cauls 3" wide to fit and when I started a dry run of the clamping I noticed that the cauls were 3/4" too narrow - or rather, the neck was 3/4" too wide. How did that happen? I'm freaking out here. One thing is to drop something by accident or execute a task poorly because of lack of experience, but this!!! What is next?

I gathered myself and cut the extra width off, measuring everything veeeeeery carefully - hands shaking, skit marks all over the place, and glued the thing together to what seemed to be a satisfactory joint. Still 17º though.

I'm really scared now!


THE WANDERING SAW CUT
TRUING THE JOINT

CHECKING THE FIT

THE GLUE-UP

CLAMP ABSTRACT

Tuesday, January 23, 2007

PREPARING BINDING

Over the weekend I started preparation for cutting up all my wood up into individual parts used for the build.

As I wanted to use the same wood for binding as I am for the back and sides, as the standard for classical guitars is, it sort of made sense for me to cut it all from the same stock.

So before I started to resaw my bubinga, the first thing I did was to cut on the three strips of veneer; maple - bubinga - maple to size, just slightly wider that the back and sides board. Then I glued them on the with Titebond III, first fastening them in position with masking tape and then clamping them on with a MDF caul.

Unfortunately, I was a bit too generous with the glue, hence the large runs down the side. At the time I was thinking about wiping it off but ended up leaving it to dry for later clean-up. When the Glue had dried overnight I scraped off most of the glue though some still remained as evindent in the last photograph. I will deal with that later.

THE BINDING VENEERS

THE BINDING VENEERS

THE GLUEING


BINDING VENEER READY

CUTTING IT ALL UP

I finally started the preparation of the individual component. It was a moment I have been looking forward to with great anticipation. Mostly because I could use my bandsaw for the purpose it was bought for - resawing guitarwoods!

FIRST CUT
For this resawing I had bought two blades: Iturra's 'Bladerunner' (identical to Highland Hardware's 'Woodslicer, only half the price) and the Lenox Carbide Tipped Tri-master, both 1/2" blades. I had hoped to use the Bladerunner with it's roughly 1/32" narrow kerf for the bubinga in order to get five 1/8" slices out of the 3/4" board. Two for the back, two for the sides and an orphan, or a spare, in case something would go wrong later in the build - I'm going to bend the sides by hand later! The five slices would also give me four strips of binding as well as an centerstrip for the back.

I put the Bladerunner on the saw, tensioned the to 15.000, tracked it and set my guides and tried some test cuts in some 9' wide maple but I couldn't get the blade to behave. It squealed and howled it's way though the stock only to reveal a cut that had wandered all over the place. I tried to lube the blade, same result. I thought maybe I should adjust the fence for drift but it seemed the blade just went randomly from left to right.
After a while I decided to give it up and try the Lenox blade instead. The Lenox blade has a considerable wider kerf, about a 1/16", so I had to give up the idea of getting five slices. But before I changed blades I cut the binding portion off and sliced it up into five as I first had intended with the whole board.

The Lenox blade was quite a different animal! I also tensioned this one to 15.000 psi, though I think the saw really got stretched to it's limits. I have an Iturra spring in it and it held the tension with no problem, but I had to use considerable force to turn the tensioning crank. It did not like the last couple of turns. I think I'll try to go a bit easier in the future and see what happens.

The Tri-master went though the stock with straight cuts, great commitment and endurance. Still noisy, though. The only time the cuts became uneven was when I didn't hold the wood steady against the fence or table. I ended up with four sliced just under 1/8" and a bit of some veneer from the last cut. It cut though the Bolivian rosewood with even greater ease. It seems that the denser the wood the easier it was for the Tri-master to cut. I did some test cut in walnut and the blade appeared to be struggling with that the most. I read somewhere that shavings from softer wood tend to swell more and fill up the gullets creating more friction and heat. I don't know if it's true, but it certainly appears to be the case here.

Lesson learned:

In retrospect I think I was a bit naive to think I could get five slices out of a 3/4" board. At least with my setup and skill level, whatever blade I used. It is nice to make the most out of what you have but being this frugal, could easily have yielded me nothing. What I did get was stock that, when all the saw marks have been planed away, will be barely about 0.100" and no definitely more. A close shave.

One side of the bubinga showed more interesting figure with darker ink lines and medullary rays and I had planed to use that for the back. Unfortunately I ended up cutting what was intended for sides into back and visa versa. It is not disastrous but a shame nevertheless. To add salt to the wound, I also forgot to cut off a bit of the end of the mahogany to use for an end block and back joint reinforcement, before I ripped it into the neck blank. One must learn to pay attention!

The little white pieces are bone for the nut and the saddle. It stank when I cut it up!

THE RESAWN PARTS


THE RESAWN PARTS

LEFTOVERS
At the end of the day I had a lot of usable left overs, well, left over. Enough for several fingerboards, saddles, kerfing, bracing, a set of bindings and a couple of face plates and lots of nuts and saddles for future builds.

Thursday, January 18, 2007

SOLERA

I finally got to finish my solera or workboard that the guitar will be assembled on. It is basically made out of three sheets of 1/2" Baltic birch plywood laminated together. The blocks are made from maple as is the soundhole clamp. The blocks sit in slots that have been cut around the rim of the workboard and can be positioned to accommodate various guitar shapes and sizes. The hole in the end of the neck extension allows the workboard to be bolted to a bench for easy access from all sides during the construction process. The holes between the blocks have been drilled to allow the use of spool clamps when the back of the instrument is glued on.

As with the plan, this concept is also from Roy Courtnall book. However, I chose not to hollow the face of the workboard out, as Courtnall suggests, in order to accommodate the dome that will be build into the soundboard.
Instead, I'll be using a cork shim to lift the soundboard off the solera. The reason for this is that I still haven't made a decision on how to deal with all the complications the construction of a domed top entails. The cork shim also appears to be a simpler and more versatile approach.

SOLERA

SOLERA

SOLERA

BLOCKS

Wednesday, January 03, 2007

PLANS

The guitar I'm going to build is a 3/4 classical with a scale length of 580mm. It is based of an reduced version of the Torres plan "Antonio de Torres 1" from Roy Courtnall's book. All measurements have been reduced to fit the shorter scale apart form the head of the guitar, that has been reduced only about 2% in order to accommodate a standard set of tuning machines.

The soundboard bracing is different from Courtnall's Torres. I have chosen to emulate Jeffrey Elliott's Torres/Hauser with the open harmonic bar. I don't have any particularly good reason for doing so, other than I was speculating that maybe the open harmonic bar would allow more of the already smaller soundboard to vibrate freely. Maybe I was just seduced by the nice photographs on Jeffrey Elliott's website.

Other than that I pretty much intend to stick with convention though chances are I might alter things a little as I go along, goof, learn, progress and discover. It has been quite fun redrawing the plan. It made me consider and investigate a lot of things I wouldn't otherwise have thought of.

SOUNDBOARD BRACING PLAN


NECK, BRIDGE AND SOUNDBOX PROFILE

MATERIALS

As this is my first build and I intend to use as little prefabricated materials as I can in order to learn as much as possible about the process. I'm sure I will at times regret this decision however, I hope it will be worth the effort and pay off in the end. Apart from tuning machines, fret wire and a few sheet of veneer for purfling and rosette this represents everything I'll be using to make my instrument from.

WOOD AND BONE

A CLOSER VIEW


From left to right: Englellmann spruce (Picea engelmannii) for the top and bracing. Bolivian rosewood (Machaerium scleroxylon) for the fingerboard, bridge and headplate. Honduran mahogany (Swietenia macrophylla) for the neck, kerfing, back bracing and endblock. The last piece is Bubinga (Guibourtia tessmannii) that will be resawn into back, sides and binding.

I bought the spruce on ebay form Kootenay Tonewoods. It was sold as a lot of five tops graded AAA for about $120 including shipping and free bracewood. The Bubinga, the Mahogany and the Rosewood all came as 4/4 stock from a local lumber yard. It was bought little by little over the past year or so and came to about $60 altogether. Both the bubinga and the mahogany have some crossgrain fractures, that I think I'll be able to avoid when they are sawn up for their purpose.

The bone in the lower right hand corner is cattle bone, also from ebay. I got them form Tropiworld who sold them in boxes of fifteen for $20 including shipping.

All in all the guitar should come in well under $150 in raw material and hardware. On top of that comes glue and finish materials and a few other bits and pieces.