The Fingerstyle Guitar - Notching the Kerfed Linings

Once the kerfed linings are glued to the sides, the sandpaper-lined concave dishes I made use of when shaping and gluing the top and back braces serve their other purpose by helping me sand a drop-off onto the edges of the rim assembly to match the curvature of the back and top plates.

I can then use a Dremel rotary tool to rout pockets into the linings to accommodate the brace ends. Using the more traditional kerfed linings whose saw kerfs face into the guitar body, there's always a danger that if one or both edges of a brace pocket happen to be in close proximity to the kerfs, a chunk of wood will be dislodged as the pocket is cut. With reverse-kerfed linings, however, the individual sections of wood between the kerfs are firmly glued to the sides and serious chipping of the exposed face of the lining on either side of the brace pocket is far less likely, provided some simple precautions are taken.

When routing the brace pockets, it's important that the Dremel is guided in such a way that the router bit's clockwise rotation doesn't contribute to tearing or chipping of the linings as the pocket is cut. This is particularly important to observe where the left-hand edge of the brace pocket is concerned (i.e., with the guitar side facing me). With that in mind, I make my first cut towards me in the direction of the guitar side along this left-hand margin, easing the router bit into the lining for the equivalent of around half the bit's diameter; a second shallow entry cut on the right-hand side of the pocket defines its width. Several light passes are made from left to right until a single recess is created between the two entry cuts. I repeat this process until the recess extends to the guitar's side and make final adjustments until the end of the brace fits snugly within the pocket. It's difficult to avoid chipping entirely, but by guiding the router in the manner I've described, it's of a minor nature and can be easily cleaned up with sandpaper.


I rout the pockets in pairs, beginning at the tail-block end of the body. If the first pair of pockets is accurately marked and cut, the centre-line of the back will be correctly aligned from that point on. If a minor adjustment to the back alignment is required, the pockets can be modified accordingly. The second, and subsequent pairs of pockets can then be more accurately positioned, with correct alignment of the back more firmly established as each pair is cut.

Some builders postulate that because reverse-kerfed linings stiffen the rim assembly once attached, there are resultant improvements in the sound of the instrument. Occasionally, it seems, views such as this are repeated often enough by individuals held in high regard within the luthier community that they become accepted as fact, whether or not they've been held up to close scrutiny. I acknowledge that I have a lot to learn and always try to have an open mind when reading of the experiences and opinions of other more experienced builders, but after looking at popular wisdom such as this from all angles, I'm left unconvinced. For what it's worth, my personal view is that while it's somewhat helpful having a stiffer rim to work with in the course of constructing the instrument, from the point at which the back and soundboard are attached to the rims, any contribution the linings may have made to the rims' stiffness is eclipsed by the strength of the top and back in compression. I suspect that in the finished instrument, the linings - reversed or otherwise - play little part beyond their primary purpose: to provide a gluing surface for the top and back plates.

Cheers
Pete

The Fingerstyle Guitar - Side Reinforcement

For almost as long as I've been building guitars I've followed the lead of others and have fitted kerfed linings to the rims, then installed wooden reinforcement strips to span the sides between the top and back linings. Although this remains common practice, it seems an increasing number within the lutherie community are coming to the view that this could potentially do more harm than good, the thinking being that if the guitar sustains a significant impact, the area of relative weakness created at the intersection of the side reinforcement and the lining could contribute to a crack developing at that point - it makes sense to me.

For this guitar then - and for its rosewood and spruce companion - I've chosen an alternative approach which is to to glue cloth bias tape across the full width of the sides at regular intervals and install the linings over the top of it. The rationale for this is that as the glue-impregnated cloth spans the entire side and will remain somewhat flexible, the weak point I've described is largely avoided. In the unlikely event that a crack develops in one of the sides for whatever reason, the tape will provide a measure of protection against the crack propagating along the length of the side - at least until a permanent repair can be carried out.

Useful Links:
Installing Side Tapes

Cheers
Pete

New Wood Purchases

I have a love/hate relationship with our strong Australian dollar at present. It's too convenient an excuse to click the "Buy Now" button when I spot particularly desirable pieces of wood on favourite web sites such as Allied Lutherie's but, of course, it's also of benefit once I've given in to temptation. Resistance is futile, it would seem.

Ample evidence of my recent weakness can be seen below. Those poor souls similarly afflicted with "Wood Acquisition Syndrome" can click the pictures for a closer look. 

European Spruce

Port Orford Cedar

European Spruce needs no introduction, but Port Orford Cedar is a relatively uncommon tonewood. Luthier's Mercantile has this to say about it:

Similar in appearance and scent to Alaskan Yellow Cedar, Port Orford Cedar is stiffer, lighter and thus more suitable for soundboards. Indeed, it is highly sought after for the bold, robust, responsive tone that it imparts on an instrument. It is very even textured, with a slight golden-white color and tight, even grain. A great advantage to the builder is that this wood is more immune to splitting than absolutely any other soundboard wood.

The Port Orford Cedar is in transit as I write this and I'm impatient to inspect it, flex it, tap it - and smell it! Aside from its promised tonal and structural advantages, I'm looking forward to experiencing the pungent peppery smell it's said to impart to a completed instrument.  It's almost worth combining it with a back and side set of Claro Walnut for that reason alone given walnut's delicious aroma.  Such an instrument would surely be the ultimate "perfumed guitar"!

Useful links:
Port Ordford Cedar - Stansell Guitars

Cheers
Pete

Kerfed Linings

Kerf: a slit or notch made by a saw

Pre-made kerfed linings are readily available from any number of suppliers, but given their expense and fragility, I prefer to fabricate my own, leaving a little more wood between the termination of each saw cut and the opposite face of the lining than is generally present on those available commercially. Even with that precaution, I like to pre-bend the mahogany strips with the aid of a bending iron to match the contours of the guitar side. Breakages are rare, but if I should happen to snap one, it makes sense to discard it, or at least reserve it for areas where the break won't be visible. Given the attention to detail lavished on the other aspects of a hand-built instrument, I find it incomprehensible when I see pictures of the interior of a guitar in which joins in the linings are in plain view through the soundhole. I'm a little uncomfortable too with saw cuts whose spacing or depth varies noticeably along the length of the strip. Using my band-saw and the crude but effective fixture pictured below, I'm able to produce evenly spaced cuts of a consistent depth.

After several less than satisfactory attempts using a router to apply a rounded profile to what will be the inner corner of the strips, I discovered that by planing a series of facets onto the appropriate edge with a small block plane, I could quickly and easily blend them into a smooth curvature with a sanding block. It reinforces the fact that sometimes, the simple, non-mechanised approach is best!

Cheers

Pete

A Claro Walnut/Sitka Spruce 000 - Free to Good Home!

I've made great advances with the last two guitars I've completed in terms of build quality and tone and I'm afraid I'm a little lacking in motivation when it comes to completing this one. I guess that's a little strange given my usual passion for guitar building, but considering that I began its construction quite some time ago and would much rather be working on my new instruments, putting into practice important lessons recently learned, I'm inclined to forgive myself for this half-hearted attitude.


The photograph above doesn't do the claro walnut back and sides justice; in its present raw state, the wood looks pretty uninspiring. Under finish, however, its stunning figure will be fully revealed and will be the icing on what I hope will be a very successful cake!

Tapping on this unusually marked Sitka spruce soundboard in its unfinished state gives me reason to be confident. The body is very resonant, the standard of workmanship is acceptable and construction is far enough advanced that I'm sure I can muster the enthusiasm to finish it. This guitar's state of completion will fall into line with my two latest instruments when they are ready to receive bindings. From that point on I'll attempt to complete the remaining steps on all three guitars concurrently.

Click for a closer look.

For what will hopefully be the last time, I plan on finding an appreciative recipient and making a gift of one of my instruments. It's certainly been very satisfying to have delivered my last two guitars to keen players free of charge, but once this guitar finds a new home, foregoing that pleasure and at last deriving some meagre income from my hobby is a prospect that's becoming increasingly attractive.  Semi-retirement (and a new band-saw) beckons!

Cheers

Pete

The Fingerstyle Guitar - Head Block, Tail Block and Linings

Having braced the top, it's time to temporarily suspend my excitement and spend some time on the rims. For me, this is perhaps the least inspiring stage of construction and the reason I find it preferable to have a ready-made stock of head blocks, tail blocks and kerfed lining strips which I've prepared in batches over the preceding months.  With a supply of blocks and linings on hand, I can make short work of fitting them to the guitar's sides and move on quickly to more interesting tasks.

I laminate my tail blocks using three layers of wood, the middle layer of which has its grain oriented at right angles to the two outer layers, parallel with the grain of the sides. For the little additional effort involved, I can feel confident that the block will remain intact and a side crack will be avoided should the guitar ever be dropped on its end pin.

In the belief that setting modest targets fuels motivation and sustains momentum, I'm setting myself the goal of attaching the head and tail blocks and installing the kerfed linings in the week ahead.

Cheers
Pete

The Fingerstyle Guitar - Soundboard Voicing

Like many novice guitar builders I was inclined to overbuild my early guitars, the mortal fear of them imploding tending to override any suspicion that I was robbing them of their full tonal potential. It's been difficult to leave that mindset behind me, but with a conscious effort to "lighten up", and with the wisdom of more experienced luthiers in mind, I'm venturing further from my previous comfort zone with each guitar in an effort to increase their responsiveness. To that end, I've significantly reduced the mass of my soundboard braces, ever mindful of the delicate balance necessary between lightness and strength. Ironically, it's because of advice from those same sources that I'm inclined to leave the soundboard itself a little thicker than I may once have done.

John Mayes' "Advanced Voicing" DVD provided me with a way forward where carving the soundboard braces is concerned. Without a doubt, watching John shave and shape the soundboard braces then tap on the top to assess the changes he'd brought about has given me a much better insight into the process than I'd been able to gain through simply reading about other luthiers' methods in that regard. As John clearly demonstrates, judicious removal of small amounts of mass from one or more braces can make a big difference to the responsiveness of the soundboard.  It's still a somewhat mysterious and inexact science for me, but recent results suggest that I'm heading in the right direction at last.

There's some carving of brace ends and final finish sanding remaining, but essentially, the redwood top is as resonant as I can confidently make it without sacrificing necessary strength. Its pitch when tapped is significantly different to that of the Sitka spruce top I've recently brought to this level of completion and it will be interesting to compare the two guitars when they're strung up. For my own future reference, I intend to document each top's overall weight and brace dimensions as well as record their tap tones with a hand-held Zoom recorder, the thinking being that over time, as I complete more instruments, I'll be able to correlate these measurements with their sound when played.

Cheers
Pete

Postscript:  Since publishing this post yesterday, I've capped the "X" brace intersection with a small piece of spruce and the relative pitches of the two tops when tapped are now much closer.  It explains the startling difference I noticed yesterday and is a great demonstration of how this small addition can significantly increase the overall stiffness of the top.