Sunday 25 August 2019

Building a 13 Course Lute, Start to Finish, 3: Veneering the Neck

Hi friends, today I want to document veneering the neck with a single piece of ebony.

If you've been tuning in to this series, you'll know that my rationale in these posts is to present a photo and one-or-two sentence description of each discrete operation in building a 13 course lute. It's not my intention to present a how-to blog, though of course there's much information to be found for those who want it.

I have to confess that, after making the first two posts in the series, I felt a little pang of something--maybe of guilt, maybe of jealousy--with which I've had to reconcile before continuing the series.

Guilt first: on one hand I'm happy to talk about my working procedures (and nobody's forcing me to do it, after all), but I've had a nagging feeling, as I've been doing it, that they are not quite mine to share. After all, I learned them from my great teacher, Grant Tomlinson; and he learned them from his own great teacher, Stephen Gottlieb. Am I not appropriating their ideas, and presenting them as my own?--And yet these procedures are mine; I've earned them with my hard work, and though they have their source in those great makers, for better or worse I've taken them and made them my own. And so, I share them humbly, and hope in so doing to show respect and pay tribute not only to Grant Tomlinson, but to all the teachers, woodworkers and luthiers who have guided me (and still do guide me) on my journey in craft.

Now, jealousy. As I write these posts, I sometimes wonder: am I not sharing too much? Am I not giving away the farm, by talking in so much detail about how I do my work? It's a good question; many makers have derived income by packaging and selling such information. Well, maybe I will too, at some point; maybe these blog posts will eventually form the basis of a best-seller on how to build baroque lutes, and my sweetheart and I will retire on the royalties to our private island in the Caribbean. Indeed!--For now, though, I've resolved not to feel jealous about sharing what I know, and what I've learned. For one thing, there is plenty of information that I am not giving away in these posts, information that can really only be imparted through personal contact between a teacher and student, side-by-side at the bench. For another, if what I offer here helps someone to build a better baroque lute, and in consequence there are more excellent baroque lutes being played, and more people listening to great players on excellent baroque lutes, then I'll count that a good thing, not a bad one. So by all means, dear reader: take whatever is useful to you, use it to build great baroque lutes, and please, pass it on.

To begin.

I've carved the neck, and allowed for the thickness of the veneer.

This is my neck veneering jig (and my cup of coffee.)

Another view.

And yet another: this view shows the length of thick cotton skate lace that I use to tie the veneer down to the neck. I use skate lace because 1) it is very strong woven cotton, and 2) it is wide and flat.

The neck must sit up from the jig at a particular angle so that the veneer will tie down closely at the edges. I've worked out this angle (and made these wedges) through trial and error.

The nut end of the neck must sit up higher than the bottom (joint) end.  
Because the neck has a slightly asymmetrical shape, it must also sit slightly askew the centreline of the jig. 

A dry run with the skate lace allows me to check whether I've got the angles right, and the veneer will tie down tightly all along both edges of the neck.

It also allows me to rehearse the best way to tie the lace around the bottom end of the neck. 

I mark out the veneer, leaving a couple of millimetres extra in each dimension.

Then I cut it out and run it through the thickness sander.

I scrape the outside surface free of sanding marks, then run it through the sander one more time (with the outside surface face-down) to take the veneer to its final thickness.

My neck, my veneer, my jig, my glue, my bending iron, are all ready to go. I'll bend the veneer and glue it, working at a fairly quick but careful pace.

I've heated a saucepan of water, which I brush on the outside of the veneer. The veneer begins to curl immediately.

I also heat the underside of the veneer on the hot plate, which helps to curl the veneer even more. (The only use I have for the bending iron is to do some fine shaping on the outer edges of the veneer, near the nut end of the neck.)

I locate the veneer carefully and hold it in place while drilling a small-diameter hole through it. 

I can then locate the end of the veneer securely with a push-pin.

I drill another hole about halfway up the neck for a second location pin.

Working quickly, I heat the neck surface and the inside surface of the veneer with a hair dryer, then brush hot glue on the neck core.

Then I brush hot glue on the inside of the veneer.

I get the veneer in place quickly, and locate it with my pins.

Then I start tying it down tightly with the skate lace.

So far, so good. I can remove the location pins...

And start applying heat and pressure with the iron. You can see I'm getting some significant glue squeeze-out through the hole for the location  pin, halfway up the neck; I also check for squeeze-out along the length of the neck, on each side.

I continue tying off until the entire veneer is tight.

I also keep ironing until I'm quite satisfied that the veneer is glued closely to the neck core, and that there are no gaps or air bubbles.

The fit looks pretty good from the nut end...

... and from the bottom end too. I clean up the glue squeeze-out with a brush, and then give the surface of the joint a coat of glue size.

At this time, I would like to introduce my audio-visual aide, whose name (for some reason) is Carl. Without his sturdy assistance, none of the actions shots of me working would be possible. Thanks Carl!

Next morning: the glue is dry, and I can remove the veneered neck from the jig. Here I am beginning to carefully saw away the excess veneer at the joint end of the neck.

I use my low-angle block plane (with the sole well-waxed) to plane the veneer almost flush with the surface of the joint. I use the low-angle plane to bring all the other veneer edges flush to the neck core as well.

Top view of the veneered neck: I think I got a good result.

The back side looks good too. No big lumps or bumps, no air pockets; everything looks solid.

Now, I will set the neck aside for at least one week before re-fitting and gluing it to the body. This is because hot hide glue, when used over a large surface such as this, will take a long time to dry thoroughly. While it dries over a number of days, it will continuously contract, mainly across the grain, but also along the grain as well. (This property of hide glue to contract as it dries is one of the main difficulties of working with it, but also, in certain circumstances, one of its great benefits.) As it contracts, it exerts a great deal of force on the woods on each side of the joint, and ends up significantly distorting the shape of the neck. The upper surface of the neck was dead-flat when I began shaping it; it's no longer anywhere near flat, either in cross-section or long section. The same is true for the neck-joint surface. By putting the neck aside for a week, I hope to allow the woods and the glue enough time to reach an equilibrium before fitting and gluing the crucial neck joint.

And so the blog will take a break as well. Happy lute making--and happy lute playing--and I will talk to you again soon.

Monday 12 August 2019

Building a 13 Course Lute, Start to Finish, 2: Fitting and Making the Neck

Hello dear friends, here's the second installment of the ongoing series, in which I chronicle the building of a 13 course lute. As I explained at the outset, what I want to do with the series is to document the stages of construction in as much detail as reasonably possible. I'm presenting photos of each discrete task, and accompanying them with a one- or two-sentence explanation of the operation depicted.

This is not, strictly speaking, a how-to blog, though of course I do hope (and in fact I'm quite sure) that much can be gleaned from my depiction of the process. Sometimes an image of a maker doing some operation, or a photo of a particular jig or setup, will be enough to spark the imagination of an onlooker who can take that concept and make it work for them in their own building practice.

However, I think that this post especially, in which I describe working with the bowl and doing the initial alignment of the neck, may prompt a lot of questions. That's natural, because my work in this stage will really lay the foundations for the instrument's final action and playability. If I work well and carefully now, I'll eventually end up with an instrument that has a very comfortable neck size and shape, a well-curved fingerboard, and string heights that are nice and low--all of which go together to create a consummately playable instrument.

I may, therefore, pause once or twice in the chronicle to give a bit of background and explanation of what I'm up to. I don't want to purposely confuse anyone (though I'm sure I'll do it anyway...)

So let us begin, where we left off last time: with the completed bowl.

Seen here: poplar top block; honduras rosewood ribs; paper rib tapes; spruce counter-cap.

This photo, and the one below, show the bowl with the false belly fitted inside. This piece of carefully-shaped 1/4" pressed board will preserve the body outline securely throughout the building process.

I've spot-glued in a few places along the side ribs to keep the false belly in place. I've used weak glue size, so that it won't be too difficult to remove the false belly when I eventually need to do so.

Here I'm marking the various depths of the 'belly scoop' on the edge rib. I will then plane this scoop evenly into the edge rib on both the bass and treble side.

I've planed in the belly scoop, and you can see how it creates a smooth curve from the bottom end, to the middle of the bowl, to the top end. 

I mark the position of the front edge of the bridge by transferring it from my working drawing. Then I stretch a length of  black thread across the body at that point, and tape it securely in place with masking tape.

I also determine the body's centreline, and tape a length of the same thread to the bottom end of the body. 
A close-up view of the crossroads.

The centreline thread is long enough that I can stretch it across the  marked centreline on the top block, and eventually use it to align the neck. 

A view from the bottom end.

After drilling pilot holes, I screw a pair of plexiglass blocks into the top block. These blocks are crucial in setting the neck at the proper angle, and keeping it from slipping forward during gluing (after the neck is shaped and veneered).

Now I can start working with the honduras mahogany neck blank.  The first step is to flatten the top surface, which I do with a low-angle block plane. (This neck blank is built up of three pieces, which were offcuts from a plank which also yielded a number of single-piece neck blanks. I glued the pieces together a number of years ago; this neck will be as stable as a single-piece neck, and will use perfectly good material that would otherwise have gone to waste.)

This is my method of determining the neck cut-off angle: I lay a straightedge from the bridge across the top block, and a sliding bevel on top of that. 

I adjust the bevel so that it matches the angle of the top block face.

A brief aside about what I'm doing here: the thread I've stretched across the body represents the position of the front of the bridge, according to the plan view; it also represents the elevation of the bridge, in relation to the edge of the bowl. Referring to my side-view working drawing, and making some careful calculations involving the height of the first string at the bridge, the thickness of the soundboard, the thickness of the fingerboard, and other factors, I can determine the angle of the top surface of the neck in relation to this string. What you see in the photo is my straightedge resting on a spacer block of a precise thickness, which I've chosen because it will allow the straightedge to rest an exact distance below the thread (which I've calculated.) 

Once I've got the angle exactly right, I can then transfer it to the side of the neck blank...

And make the cutoff by adjusting the bandsaw table to the proper angle.

I then refine this angle with a low-angle block plane and, at the very last, a sanding block. This surface must be dead flat, and I check for flatness carefully with an engineer's square.

Holding the neck in place with the left hand, I bring in a straightedge to hold against the neck surface. This allows me to check the angle of the neck surface in relation to my bridge thread. 

I've stuck a bit of steel tape measure to the corner of the straightedge, so that I can see exactly how far below the cotton the straightedge sits. I will adjust the neck cutoff as needed with the low-angle block plane, files or sanding block, until the angle of the neck is exactly what I want.

When I've got the angle, I size the end-grain of the neck cutoff a number of times with hot diluted hide glue.

I also brush a few coats of size on the top block surface. I let both surfaces dry overnight, then re-fit the next morning, making sure one more time that the angle is exactly correct.

When I've re-fitted the neck yet again, I mark the position of the neck screw by pushing a shop-made awl through the screw hole in the top block.

There's my mark.

I have a good solid jig that I can clamp the neck to, to hold it upright while I drill a pilot hole.

Your humble narrator, in action, drilling the pilot hole for the neck screw.

Once the pilot's drilled, I can screw up the neck, and bring up the thread to mark the centreline.

And once I've done that, I can lay out the edges and centreline of the neck. (As you might notice here, the centreline of the body and that of the neck do not coincide, which is often the case with 13 course lutes.)

Here's me laying out the neck shape at the nut end. Note that I will prick along the inside line, subtracting the thickness of the neck veneer.

There's my neck profile at the nut end.

And here's my neck profile at the body-neck joint. Note that I've marked an inside line here too, to allow for the thickness of the veneer.

The first step in shaping the neck is to shape the long section only.

There's the long section: note how the line quickly re-curves as it comes away from from the body-neck joint, then flattens and tapers evenly out toward the nut end.

I shape the neck using, first, a spokeshave and small fingerplanes, then the low-angle block plane, then rasps and files, as you see here.

The re-curve in the long section, along with the change in cross-section profile from a near-semicircle at the body-neck joint to a very flattened profile at the nut end, make this neck a very complex shape to carve gracefully. This photo shows the nearly-finished shape.
As a final check, I screw the neck to the body to make sure I've left the correct space for the veneer.

And then, at the end of a long, long, long, long, long, long day, I sweep up.

I hope you've enjoyed this, the second installment of "The Tedium and the Triumph." So far much tedium, not too much triumph. But it does feel good to get a good shape on the neck, and I'm looking forward to veneering the neck next week, which I'll share in the next installment.