Friday, March 22, 2002

Mandolin #1: Neck

It's always the neck that makes me nervous. It seems that with good materials you can't go too wrong on the body. Sure, maybe it won't be the loudest or most balanced, etc. But with the neck, and particularly the fingerboard, if you mess up, the instrument's just not going to play.

Cutting the Fingerboard
Cutting out the fingerboard from the blank seemed like something I couldn't mess up too bad. I traced the outline of the fretboard from a plastic template made from the blueprint and started hacking away. Well, coping saws are not exactly the best tool for cutting a straight line. In fact, one of my side cuts had actually crossed into my traced outline. No problem, it's a big fingerboard blank. I just reoriented my template and traced another outline. Okay, this is a test. Anyone paying more attention than I was at the time? Well, with a preslotted fingerboard blank, orienting the template anywhere other than right down the center is going to result in some slanted frets. Well, I didn't realize it until too late and fortunately it didn't look too bad. I had no idea whether one would be able to tell one she was strung up. I was being realistic and thinking that it was somewhat unlikely that my first fingerboard (much less the rest of my first mandolin) was going to play at all. It was more likely that I might have to hand it over to the pros for a new fingerboard anyway so I should just keep plugging forward.

Fingerboard outline 

I was able to straighten my crooked sides by clamping the fingerboard in my bench vise and sanding it with my flat sanding board. I just kept at it until I got down to my outline. Some sanding and filing of the fingerboard extension got everything ready for binding. You may also notice that I scalloped the fingerboard extension. Yeah, um, I did that because of, uh, like, my picking style, and, uh, so I could minimize pick noise on studio sessions... Okay fine, the proximity of the frets and the narrowness of the fingerboard extension made the slight offset of the fret slots look more pronounced. I had considered scalloping the extension anyway for some of the reasons above and decided that hiding my fingerboard trimming mistake was a good enough motivation to go for it. I set the depth on the Dremel router base and just worked from the end of the extension towards the nut. Much easier than I thought it would be a definitely a modification I would feel comfortable attempting on another mandolin (though whether I like the fingerboard scalloped is yet to be seen).

Trimming fingerboard Scalloped fingerboard extension 

Binding the Fingerboard
Using a setup shown in the MacRostie video, fingerboard binding went smoothly. There was no channel to cut. The binding is just glued to the side of the fingerboard. I think MacRostie used way paper to prevent everything from sticking to his work surface. I used a scrap piece of Melamine (sp?) which worked well. Starting on the long side of the fingerboard, I clamped using blocks before bending around the extension. I heated the binding with my wife's BigHair 4000 Handheld Hair Elevation System and bent it around the extension using the end of a pencil to push into the tight curve at the end. Starting with a new piece of binding from the other side, I used the same method of clamping the straight section before bending the tricky parts. I had to get creative with clamps and the end of a pencil to hold everything in place and keep the curves tight against the fingerboard.

Binding fingerboard 1 Binding fingerboard 2 Binding fingerboard 4

 Binding fingerboard 5 Binding fingerboard 6  

Position Markers
You can see in the third picture that I added the position markers while some of the binding was drying. Though I carefully located the center of each fret space by finding the intersection of lines drawn diagonally from corner to corner, as soon as I started drilling, the bit wandered and each hole ended up a little different. In one case on, one of the higher fret spaces where the frets are closer together, the hole actually started to blend into one of the fret slots. Of course, the markers are a purely aesthetic (or at least purely visual) feature so it doesn't really matter but it looked a little sloppy. I guess the correct procedure is to use a smaller bit to start the hole so the larger bit will remain centered. In any case, the position markers came cut with the kit so installing them was just a matter of filling the hole with thin superglue and sliding the dot into the hole. I then did what MacRostie did and added some more superglue around the edges of the dots. The glue was thin enough to slip down the sides of the hole and any excess would be sanded off in the leveling anyway.

Cleaning up the Fingerboard
Using a mixture of ebony dust and Elmer's white glue, I filled any spots where fret slots had been torn when the fingerboard was being trimmed and where my position marker holes had strayed too close. I could then use my flat board with adhesive sandpaper to sand the fingerboard level. I then used increasing grits of sand paper up to 400 or so to hand sand to a nice smooth finish.

Filling fingerboard cracks 2 Leveling fingerboard binding Filling fingerboard cracks 1

Side Position Markers
Side position marker material comes in a thin black rod. I drilled holes by eye in the binding on the side of the fingerboard. I know, you're probably all impressed that I remembered to make sure the markers were on the treble side of the fingerboard so they could be seen from above by the player. Once the holes were drilled, they were filled with super glue and one end of the side position marker rod was inserted and nipped off just above the binding. Then with the fingerboard clamped in the vise, the side position marker ends were sanded flush to the side binding.

Fingerboard side markers 2 Fingerboard side markers 1

Shaping the Neck
With the binding on it, my neck button (protruding from the back) was almost as big as the neck heel. As a result, some shaping was needed on the heel but there was not a lot of material to remove. With the neck clamped in my bench vice (and kept there by a nest of rubber bands), I went to work with a rasp. My goal was to remove some material and to create a general "V" shape near the nut and flattening as it approached the heel. The second picture on the left shows the heel rounded on one side and the "V" shape starting to appear. I had some idea that I wanted a fairly low profile and didn't want it too massive near the heel (hard to finger chop chords up higher when you have to reach around the heel) but basically I just went by feel comparing it to other mandolins until I liked the what I felt.

Shaping the neck 1 Shaping the neck 3

Shaping the neck 5 Shaping the neck 6

Installing the Neck
After some careful final checks using my meticulously calibrated cardboard template, I determined that I was as confident in my neck as I always had been and got out the glue (gasp). I had to use some scrap blocks positioned around the top of the dovetail as clamping cauls because the 15th fret crosspiece prevented the clamps from applying pressure to the top of the neck. With the neck securely in place, I trimmed the crosspiece flush with my dovetail saw. The fingerboard extension support only required some basic shaping and rounding. Before it could be glued in place, a flat spot on the top next the to the crosspiece was needed. Through a combination of sanding different bottom angles into the extension support and using a small sanding block on the top, I was able to get a flush fit between the end of the support and the crosspiece and glued and clamped the support in place. Finally, neck, crosspiece, and extension support needed to be leveled together to provide a flat surface for the fingerboard. Working with my flat sanding stick and some sanding blocks, I came to realized that the end of the extension support was angled upwards a bit. Though it took some time and repetitive effort, the protruding wood eventually yielded and I was left with a level surface and tight joints between all three pieces.

Gluing the neck Leveling the crosspiece  

 Shaping the fingerboard extension Gluing the fingerboard extension Glued and leveled fingerboard extension

A final aesthetic touch was to carve a concave curve into the fingerboard extension support and 15th fret crosspiece on either side of the fingerboard. I suppose it was originally done just to  remove the corner so it wouldn't get in the way, but it's really a nice looking effect. Here’s a pic from later in the process…

Crosspiece curve

By the time I got to the last few frets, I had developed a workable fretting system despite my makeshift fretting tools. Before any frets could go in, each slot had to be cleaned of saw dust, binding glue, super glue, etc. I mostly used an xacto knife with a regular blade although there is a hook blade available that looks a lot like the fret slot cleaning tools available from luthiery suppliers. My process was to start with my tiny nippers slowly clipping (or nipping if you prefer) from one end below the fret bead. Then I would come up from the bottom to clip off a small section of the tangs. This part of the wire overhangs the binding on one side of the slot. I would then lay the wire across the slot and mark the needed length. I think a good set of fret nippers would allow you to just come up from the bottom and nip out a section of the tangs. With my system, I had to nibble (nipple?) away at the tangs with a corner of the nipper slowly creating a gap in the tangs. Nibbling too much at one time would bend the wire. With the gap nibbled, I used the remaining length of the wire to stabilize the end and keep it from rolling. Unfortunately, I think the hammer I chose may have been made by the same people who make those Superballs making it somewhat awkward to find the right level of impact without having the hammer rebound and hit me in the forehead. Okay, that may be a slight exaggeration but my hammer was too soft and would cause my whole set up to bounce around the table with each smack often vibrating the last fret I'd done out of its slot. By clamping everything to the table and sliding my clamping caul along the fingerboard as I went, I was able to make the system work. Anyway, on the rare occasion that the frets seated securely in the slots, I would nip them just beyond the binding and move on. As I said, by the time I got to the end of the board, the frets were going in much more smoothly. Now, does anyone know what those high frets are for (mandolin player joke)? In any case I knew I would be revisiting the frets after she'd been strung up so I did my best and moved on.

Once all the frets were in place, I clamped the fingerboard in my bench vise and cleaned up the edges with a file and a flat sanding stick. At this point, I was not worried about a proper fret dressing. I just wanted to get the fingerboard on the mandolin.

Fretting 1 Fretting 2 Fretting 5

 Fretting 6 Fretting 8 Fret ends 2

Index of Project


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