Broken truss-rod replacement
Truss-rods can fail. Sometimes because of over-tightening, sometimes when the hexagonal keyway has been rounded (with an undersized or worn allen key), sometimes when they rust and seize after being kept in damp conditions, and sometimes because they were under-engineered in the first place. And sometimes for no obvious reason.
I now grease all truss-rod threads, so that even should the guitar be kept in damp conditions (which of course it shouldn’t for several reasons), the threads should not rust. And should turn more easily in all conditions.
Daniel Clark recently sent me his 1989 Model 1 guitar with a non-functioning truss-rod. This truss-rod was made of a steel rod in an aluminium channel, as were most at the time of building. One end of the rod is fixed to the end of the channel, the other is threaded with a long Allen nut working against the other end of the channel.
Tightening the long nut against the threaded end of the rod shortens it, and as the channel is of fixed length, the channel has to curve. Because the truss-rod is tightly enclosed, it bends in its entirety with the longer channel back to the outside of the shorter rod, bending the neck with it.
Old type steel and aluminium truss-rod
Modern truss-rods are simpler and more compact. The rod is threaded at both ends, one standard and one reverse thread, and runs through long nuts attached to each end of a narrow flat steel bar. So turning the rod (with an Allen key in the rounded end) one way shortens it (and the other way lengthens it) against the fixed length bar, thus bending it.
Not only does this have less work to do (not having to bend the sides of the channel), it also eliminates the problem caused by different expansion rates of steel and aluminium. It also permits pulling the neck forward if required.
Modern double action all steel truss-rod
When Daniel’s guitar arrived, turning the long Allen nut was effortless but had no effect. So the truss-rod had to come out.
The standard procedure is to remove the fingerboard (complete with frets), so the truss-rod can be changed, replacing the fingerboard afterwards. My problem with this method is that it damages the finish, not only between the fingerboard and the neck but also, more importantly, between the upper portion of the fingerboard and the soundboard. Touching up old finish on a soundboard is a problem, it will always show. So I came up with a different method.
Rather than remove the whole fingerboard, I take out the frets and cut a slot in the fingerboard above the truss-rod so I can remove and replace it. I do this with a router mounted on a simple plywood jig.
1. Here is the jig mounted over the fingerboard. I removed the frets and routed out the area above the broken truss rod, enabling me to lever it out. The mahogany neck is visible at the bottom of the slot. The old truss-rod is alongside.
2. The new truss-rod is in place. As it is narrower than the original, I set pieces of Blackwood on either side so the truss-rod is a snug fit. As the rod underneath now has to turn, it is lubricated with graphite powder to minimize resistance.
3. I cut a piece of ebony of the exact size to fit the slot and fitted and glued it in place, pressing it gently onto the truss-rod. I checked that the truss-rod can still turn freely.
4. I trimmed the ebony insert down to match the level of the existing fingerboard, cut the fret slots in it, and replaced the centre Mother of Pearl dots.
5. The old frets were worn, so after checking the fretboard is level, I replaced them with Evo Gold fretwire. This is much harder than the original nickel silver and will last much longer without pitting.
6. Now strung up, it needed just a tweak on the truss-rod, and it’s perfect. The only way the repair shows is that the new ebony is a little blacker than the original, but a quick oiling minimizes even this. With the 3rd and 4th strings over the joins, it is almost impossible to see. And no damage to the finish.
Click on the image to see a larger version.
When I removed the old truss-rod, I found the thread had stripped, allowing the nut to turn freely without shortening the rod. On examination, I saw the rod was thinner than on some, as was the threaded end. It was also installed at a time before I greased the threads.
The fingerboard repaired, with new frets and new truss-rod, is now better than new and the instrument sounds excellent. In fact, better than before. This guitar will become shortly become available to purchase and will appear on my ‘Available now’ webpage.
Douglas Fir bracewood
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Douglas Fir is a lovely honey coloured softwood. When close grained, it makes excellent guitar soundboards. These give a strong, characterful bass and a clear treble. Being light and stiff, Douglas Fir also makes excellent brace wood. Here are rough cut bracewood pieces resting just above my warm workshop stove.
It has been suggested that when Stradivari first set up building violins he was short of well seasoned spruce (he will have used Italian spruce coming from the north), so put less seasoned wood into his chimney, letting the hot fumes ran past the face of the soundboard wood and drying it reasonably quickly. Kilned wood is dried much faster by high temperatures which changes the chemistry of the wood in a way air drying and the relatively slow drying in the passing warm fumes from a stove or fire do not.
I should add, I don’t know how reliable the Stradivari theory is.
When having a classical guitar built (in a time before I was building instruments), the sides picked were hanging in front of a radiator, so drying in a similar fashion.
Having bought three blocks of Douglas Fir for braces, I cut the first into slightly oversize pieces, taped them together and placed them on my warm workshop stove, left on day and night. They were edge on to the heat, allowing the warm air to run past the face of each brace in much the same way as Stradivari is thought to have dried his spruce.
After a few weeks, the wood is dry and resonant, ringing beautifully when tapped.
1980s F-hole mandolin
Yesterday Robert Boyett visited with two of my older mandolins. One was my standard model of the 1980s, with Indian rosewood back and sides, a German spruce soundboard and an oval soundhole. The other had maple back and sides, a carved back and a German spruce soundboard with f-holes.
This second one greatly surprised me. I later built a small (Gibson size) mandolin with f-holes, but it was in my mind this was the first and only one. However, there is no doubt I built this one. All my design and build features are present, along with the address card type label of the time.
The f-holes are unusually large, and I now recall matching their combined area to that of the oval hole in my standard mandolin. The soundboard is braced with tone bars running the length of the body rather than the X bracing on oval hole models. The label is unfortunately undated, but I used this style until the late 1980s.
Deeper than our current mandolins, it sounded truly wonderful with a fat, rich sound. Robert has many mandolins but said he always goes to this one. Clearly well looked after by its three owners, it’s in virtually new condition. Robert was thrilled with it, and rightly so.
Food for thought.
Well on the way
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As a contrast to the soundboard below, this is a guitar is approaching completion. Here the Wengé neck has been jointed to the body; next the truss rod and slotted fingerboard will be added.
Very early stages
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A new instrument is begun long before its actual build. This Anniversary D model guitar will be built several months from now, but the soundboard and back will be braced and set aside in advance.
Here is the Douglas Fir soundboard with ebony logo inlaid, and also shown is the headstock with it’s Birdseye maple logo.
Knitted toys
Hexham is a delightful small market town. One of its charms is a group of knitted toys on the market square post box, regularly replaced with a new set. It says something about Hexham that these toys stay out day and night unmolested.
Today’s selection
Hexham Bluegrass festival
This weekend is the second Hexham Bluegrass festival weekend. Light rain on and off, but the bandstand in the Abbey Grounds is a great setting whatever the weather. These photos were taken not long after they set up, plenty more people arriving later.
The Saturday Bandstand session opened with the Byker Hillbillies
Development New World guitar for sale
Now Sold
As well as the Douglas Fir/Brazilian rosewood guitar below, I am also selling a development New World guitar.
It has back and sides of Katalox, also known as Mexican Ebony. I came across it when visiting Keystone Guitar Tonewoods in Essex a dozen or so years ago. I was intrigued by its ringing tap tone and close grained dark appearance, so bought a couple of sets. They sat on a shelf in my warm shop, air-drying and half forgotten for over a decade, until last year when I took them down, tapped them again, and couldn’t resist building one into a guitar.
The soundboard is close grained German spruce, with my inlaid ebony logo on the shoulder.
It has my preferred Highlander pickup fitted.
I strung the New World guitar in November 2023 and was captivated by the rich, smooth and even sound. The bass is strong and smooth, the treble strong and clear without a hint of edginess. I love it; this is a guitar for life.
I shall build more Katalox guitars, though it can be hard to find. I found only two sets on offer in Europe and bought them both. So I now have another three sets.
Katalox has another advantage: it isn’t listed on any CITES appendix so exporting is easier.
Specification New World K
Soundboard: | German spruce |
Back and sides: | Katalox (Mexican ebony) |
Neck | Wengé |
Fingerboard: | Ebony |
Bridge: | Ebony with two piece bone saddle |
Binding: | Santos rosewood with red/gold/green purfling |
Trim: | Birdsfoot edging with red and black purfling |
Body Width: | 402mm (15.8″) |
Body Length: | 495mm (19.5”) |
Max body depth: | 101mm (4.0”) |
F/b width at nut: | 45mm (1.75″) |
Scale: | 643mm (25.3”) |
Tuners: | Gold Gotohs |
Pickup | Highlander |
Price
The New World K is priced as a New World African Blackwood at £11,250.00. While unmarked, it has been with me for seven months so the cost is £10,500.00 including Hiscox Artist Line case and Highlander pickup.
US price is $15,000 including shipping and insurance. Katalox is not CITES listed so shipping is straightforward. As with the Douglas Fir MS, this is an opportunity to buy from me without the usual wait.
2023 Douglas Fir / Brazilian rosewood MS guitar
I am selling a 2023 Douglas Fir and Brazilian rosewood MS guitar, the first Douglas Fir MS I built. It has a fitted Highlander pickup and is completely unmarked, having spent the year with its super careful owner, Benji Lock-Powell. Benji is parting with it for personal reasons.
I have now built three guitars with Douglas Fir soundboards and all are exceptional. As well as being beautiful to look at, Douglas Fir gives a truly bright treble along with a rich characterful bass. I personally love it, and am currently building a New World with a Douglas Fir soundboard for myself.
The guitar’s Brazilian rosewood has full CITES certification, which will be provided to the new owner. As the photos show, this particular set is special, strikingly figured with green edging showing in natural light. The finish is excellent, the photo of the back below perfectly reflecting the room around it.
It includes a fitted Highlander pickup (the best) and comes in a Hiscox Artist line case.
Click on photos for larger images
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Priced at £11,000 ($15,000 to the US including shipping), £4000 below new list price, this is an opportunity to buy a very special Brazilian rosewood guitar immediately.
For any queries, please contact me by email stefan@sobellguitars.com or telephone me on 07740 600 282.