Making a Ladder Braced Harp Guitar

2007 was the year of making "different" instruments for me - a Lap slide Weissenborn style guitar followed by a ladder braced Concert sized guitar. Next I wanted to try a harp guitar. My original plan was to make one based around Samhain - my Grand Concert style guitar and I have bought in a Lutz top set from Shane Neifer at High Mountain Tonewoods for this, but having made Jack the Lad I was fascinated by the concept and sound of ladder bracing. So my first harp guitar build was a "prototype" based around Jack the Lad. I am also interested in using multipiece tops and backs to make the most use of a scarce resource - tone wood, so "Jacob" (Jacob's Ladder - get it?)  had a 6 piece English walnut back and 4 piece Lutz top. The Lutz was Shane's "packing grade" and was used to protect some East Indian Rosewood sides I got from him, but having been a tree for lots of years and come across the Atlantic Ocean as a bridesmaid rather than a bride, this wood deserved better. To make best use of my webpages this is a long page and you will have to scroll a long way down to see it all. Hopefully it's worth it:

 

Start with the "cunning plan" or at least the start of the plan. This will be a 12 fret body join, slotted peghead with 625mm scale length. Six extra bass strings will be carried over a hollow neck and finish in another slotted peghead.

This is the mold.

And here is the six piece English walnut back, together with the sides. This will be a slim guitar - aroind 3" deep - maybe just a fraction over.

Here is the six piece Lutz top. Even Shane's packing Lutz is quatersawn with fantastic cross-silking and it has a very promising tap tone.

First side in the Fox Bender. The long piece at the front will make taking it out interesting!

Here's the side out of the Fox Bender. It needs a bend by hand on the hot pipe.

The second side is bent in the Fox-bender for the lower bout and waist shape and finished off on the hot pipe by hand to fit the mold. Then the tail block is made and glued in. I am using fish glue for this.

Here is the tail block glued in place.

Next I want to make the peghead for the six sub-bass strings so that this can be glued to the sides. This is a very similar process to the Weissenborn-style guitar build. Here is the peg head in rough shape, using a block of English walnut to match the sides.

You can see the rough shaping of the underside here.

The top face has a cocobolo veneer on it - to match the slot-head of the guitar six strings and here it is being glued in place. I want to use hot hide glue and fish glue where possible on this instrument, but cocobolo can be tricky to glue and I know from Jack the Lad that Titebond works well. So Titebond it is.

Here's the peg-head cut to shape and the positions marked for the slots and holes for the tuners.

The tuner holes are drilled first using this neat jig.

Here's the result.

Then the slots are routed out.

Here the inside of the slots have been cleaned up with files and sandpaper and the initial ramping done.

Here's the peghead with the portion that goes in the hollow neck shaped to accept the sides.

The sides are cut to the right length and then glued onto the peghead. I am using fish glue for this.

Next I make the mahogany neck block that will hold the adjustable neck and carbon-fibre buttress braces. For more details see my adjustable neck page. I am using fish glue to attach the neck block.

Here's the neck block glued in to the side rim assembly.

I now make the soundhole re-enforcement plate and the bridgeplate. These are both made from spruce with the grain perpendicular to that of the main top. These are glued on in the go-bar deck using hot-hide glue.

The soundhole (94mm diameter) is then cut.

Next the spruce bridgeplate is routed to the depth of 1.5mm to accomodate a strip of Old Rio Rosewood where the ball ends of the strings will be.

Here's a dry fit. The Rosewood plate will be glued in using hot-hide glue in the go bar deck and when dry it will be sanded flush with the rest of the bridgeplate.

Now the first two ladder braces are glued on using hot-hide glue. The bottom of the braces are radiused to 10'.

The third ladder brace has been glued on together with the two A frame braces. These will be carved down so that the final ladder braced can be notched over them. The ends of the A frame braces will be glued into the neck block. I won't profile the braces and voice the top until just before I am ready to close up the box.

The final ladder brace is glued in after being notched to span the A frame braces and drilled to allow for truss-rod adjustment.

The top is cut to close to the final shape and then tested for fit to the sides. The brace positions are marked on the side.The sides for the top are then profiles and Spanish cedar reverse-kerfed linings glued on with fish glue. When the glue is dry the linings are sanded to the correct profile. The top ladder braces are initially shaped (final voicing of the top is done just before closing the box) and pockets for the brace ends routed out of the kerfed linings.

The top is again tested for fit - this time outside the mould.

Here's a side view.

Now for the back. The back ladder brace positions are marked and the East Indian Rosewood centre seam reinforcement strips glued in using hot hide glue

The back braces are glued on in the go-bar deck using hot hide glue. The bottom of the braces have been radiused at 10'.

With the braces on, the back is checked for fit on the rim-set, the braces cut to the right length to fit and the back cut to the right shape. The harp arm is left with some extra width on each side and will be cut to the exact shape just before gluing.

The sides are then profiled to the back curvature and the harp arm profiled to meet the peghead. Planing with a small block plane is one of my favourite tasks - very relaxing and satifying.

Having marked where the back brace ends are on the outside of the sides, the Spanish cedar reverse-kerfed linings are glued in with fish glue. The linings are notched to accept the top and back braces, spruce side braces are notched into the linings and glued to the sides, carbon fibre buttress braces are attached to the headblock and sides, and the end graft of cocobolo flanked by ebony inlaid and glued into the rim . . .

. . . then the back can be glued on. I am using fish glue. No clamps are required as the sides are profiled to take the back shape - I use brown tape to hold the back on while the glue dries.

The back is trimmed flush to the sides, and then the side soundport is cut out after first re-enforcing the side where it goes with thin veneers. I also have made up a latice of carbon fibre braces for the hollow arm supporting the 6 sub-bass strings.

Here is a side view showing the soundport.

The top is voiced and signed.

Here is a view of the "triabolic" braces. The braces ar just under 6mm wide and vary in height from 13-16mm.

Then the top is glued on with fish glue. I have used 2 clamps at the head-block to make sure good contact is made.

The scarfe joint is cut on the walnut neck piece using my home made jig.

After truing up the pieces they are glued up using hot hide glue and the same cutting jig.

It's interesting how the Muses of guitar making intervene from time to time to influence a build. This was meant to be an English walnut neck but while routing the truss-rod slot the router bit decided to come loose and drilled a perfect hole in the middle of the neck before hitting the floor with a musical clunk. Well now it's a laminated neck of walnut/ mahogany/ rosewood/ mahogany/ walnut. Here are the pieces being clamped together after glueing with fish glue.

While the glued neck is curing it's time to think of binding the body. Old joke: "How many luthiers does it take to change a light bulb? Only one but they have to make a jig first!" Well this harp guitar is certainly a different shape and so I had to make a jig to hold it while I cut the binding channels. Here's the result. Hmm . . . tomorrow's Friday 13th so maybe it will be a good idea to do something else.

The binding and purfling channels are routed . . .

. . . and the binding and purflings are carefully tested for fitted, adjusted and then glued in and taped up.

Here's the body after the bindings and purflings have been scraped level.

Back to the neck. The truss rod channel and the two channels for the carbon-fibre rods are routed.

Here is the neck with the truss-rod installed, walnut cap glued on, carbon-fibre rods glued in and the whole surface cleaned off and levelled.

Now begins the complex job of getting the fingerboard side purfling to seamlessly join with the headstock side purfling. First a piece of walnut the width of the nut is glued on where the nut will be . . .

. . . the small piece of wood is then sanded to meet the plane of the headstock. The neadstock veneer is glued on, and then the headstock is bound with matching cocobolo, with a bwb purfling on the bottom - the binding is glued and taped here in the photo. The channel is routed so that the bwb of the headstock veneer meets the bwb purfling of the fingerboard . . .

. . . like this.

The fingerboard has been slotted, bound and is glued to the neck, the headstock slots cut, a backstrap cocobolo veneer put on, the neck shaped and bolted to the body. The bridge has been slotted for the three saddles, the twelve bridge-pin holes drilles and countersunk and rough shaped.

The finish has been applied to the main body - the back and sides had Z-Poxy pore filler and the top a shellac wash coat and then the body sprayed with pre-catalysed lacquer. The bridge was placed in the correct position and three of the bridge-pin holes drilled through. The bridge outline is carefully scribed on the top and the lacquer removed inside the scribe lines.

Here's a trial fitting of the bridge. The bottom of the bridge has been profiled to match the shape of the top where it will be glued.

The bridge is then glued on using hot hide glue.

Set-up is a little more complicated than usual but follows the same steps as my other builds shown here. This is the end result - small and compact and pleasing to the eye.

It made it's debut with me at the 2007 Burwell Bash.