Mopus chapter 7: The End is Near! (Part 2)

Now on to making the fretboard.  What I was really after was not just a way to make this fretboard, but future ones as well.  Here’s Mopus’ future ebony fretboard being trued up:

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The biggest challenge in making a fretboard is to cut very precisely located slots for the frets to be installed into – the positions which are determined by the overall scale length. The slots have to be very clean, cut to a constant depth, and the width must be precise. There are various expensive ways to tool up for this operation – either by using a fancy miter box, or by using a table saw outfitted with a special (and therefor pricey) blade, but I wanted to come up with my own solution.

Besides cost, there was another reason I wanted to go my own way – I’m already planning the next guitar, which will have fan frets. A fan fret guitar (also called a multi-scale guitar), has frets which are not parallel, but spread out like a fan. The reason for this is to allow the bass strings to be longer than the treble strings. Google “fan fret guitar” if you’re curious about what I’m talking about. The problem with all the fret slotting solutions I mentioned above is that they assume all the frets are parallel.

So once again, I’m investing a lot of time and thought towards creating a tool just so I can make something else. Here’s what I came up with:

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There is a long fence that the fretboard seats against to keep it perfectly straight, and two lever clamps to lock it down. The saw is held in perfect horizontal alignment by use of 3 very high powered magnets embedded into a cross fence made of maple. This fence can swivel to cut any angle, and is locked down by a bolt. The saw has a blade whose kerf is exactly the width of the desired slot. The surface that the blade is stuck to is highly polished, so that the saw glides very easily, yet is held against the side with over 70 pounds of force due to the magnets. The depth of the slot is controlled by the height of the cross fence, the top will hit the ridge at the top of the saw blade when the depth is reached.  Got all that?  No? Well, the important thing is that it seems to work very well…

But now getting back to this guitar, all I need are standard parallel frets, so all that mumbo jumbo about fan frets is for sometime in the future. In this case all I had to do was lock the cross fence down at 90 degrees and begin sawing. Here’s the slotting jig in action:

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I did use a template and an indexing pin so that I didn’t have to think too much about exactly were the frets needed to be. For each cut you just index to the next position in the template and go.

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After tapering the fretboard sides on the bandsaw, I worked on the fretboard radius. This is a curve on the top of the fretboard to make it easier on the musician’s fingers. I chose a 16 inch radius, mainly because I already had sanding blocks for this.  I used makeshift fences to keep the radius even down the length of the fretboard. The fretboard is held in place with double sticky tape.

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Much elbow grease and some sweat and swear words later, I had my fretboard. Now for some fret markers.

I tried out a few fret marker ideas, and settled on a “random angle” design made from gold mother of pearl.  I just wanted something different, but not that hard to pull off.

I pulled out my nifty shell cutting jig (with the all important vacuum attachment) from 3 years ago, and cut some shell blanks:

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To inlay the shell, I first scored the outline, then filled it with chalk so I could see it. I used a Dremel with a special base and inlay bit to cut inside the lines.

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And I was able to get a pretty good fit. It doesn’t hurt that I’ve done this sort of thing a few times now.

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I used black CA glue to install the markers. It seems to blend pretty good with the ebony, and it’s certainly easier than the epoxy / sawdust method I had used before.  After some sanding and filing, here’s what my fretboard looked like at the time.

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That’s curly maple on either side of the fretboard, which I then glued on to dress things up a bit more. I also decided to put a curve at the very bottom of the fretboard (the part that will touch the sound hole).

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Since I was already cutting shell, I figured I should make the headstock logo at the same time. I originally thought I’d use blue abalone for this, looking cool and all, but after comparing against gold MOP, I went with the latter. It just stands out more IMO.

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After doing the headstock inlay, and a bunch of sanding and cleaning, I was anxious to see what Mopus would look like one day. Laying all the pieces together, Mopus is starting to resemble an actual guitar!

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The next steps are to install the frets and make a bridge. Those things are already done, but I think that’s enough info for today. Stay tuned for the super exciting part three of this update, coming to a theater near you! OK, maybe not a theater.

Mopus chapter 6: The End is Near! (Part 1)

My last Mopus update was way back in November, and so much has happened since that it almost seems like last year. Wait…

Mopus is getting close to being done. By “close” I probably still mean 3 or more weeks, but it’s clearly almost a thing at this point.  Here’s a story of how a couple pieces of nondescript wood became a guitar neck.

I started innocently enough with a nice but boring bit of mahogany.

The neck blank I’m using is not thick enough to carve out a headstock and a heel, so the idea is to build up those areas by cutting off pieces and gluing them back where needed. To begin with, to make the headstock I made an angled cut to glue back as a “scarf joint”.

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Here you can see how this already suggests a guitar headstock.

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Sure I could glue this up right now, but on this project I’m not really ever looking for the easy way out. So to make a more interesting neck, I sliced the board right down the center and laminated in three wood strips (maple flanked by purple heart) to create a center stripe.

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After gluing on the bit I previously cut off, and spending some quality time with some planes and other tools, I wound up with with this, which I think already looks pretty cool:

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But the headstock is way too thick for actual guitar tuners, so that part had to get a lot thinner:

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At this point I decided to take a detour and take care of something that has been bothering me for a while – the workbench I’d been using was small and wobbly. So, I made myself a heavy, sturdy and much larger workbench. Now we’re talking!

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I also made myself a router table at the same time, which I would need to finish the neck.  Yep, still another side project. In my guitar making experience so far, these kind of side trips seem to be the norm.  It’s a pretty true statement that guitar making (and likely wood working in general) is mostly about making things which enable you to make things.

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Armed with the router table, I could now cut channels in the neck for the truss rod. While I was at it, I also routed out channels for two carbon fiber rods which should make for a pretty stable neck. It was a bit of a mini project finding a source for carbon fiber!

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Next up was to glue the heel block on, and while I was at it, I figured I’d also glue on the headplate at the same time. Previously I had found and prepared some bookmatched striped Macassar ebony into a headplate, which I had all ready to go for this moment.

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And after a little cutting, trimming, rasping, and filing, this is what the neck looked like:

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Now to address attaching the neck to the body. This is not the easiest thing to do. I decided to use a mortise and tenon design with bolts (as opposed to the traditional dovetail joint).  These days, this is considered a better design, because it is much easier to adjust the neck angle should it become necessary.  The challenge is to cut a precise mortise in the guitar body (without destroying it), and to cut a precise tenon in the guitar neck. The angle between the neck and body is also tricky, as for various reasons the neck has to be at a calculated angle of about 1.5 degrees. Even a tenth of a degree makes a huge difference in playability, so this is not something one does freehand. A custom made jig is really a must, so I spent weeks designing and building such a jig.

I came up with a design that would work for both the mortise and tenon, using templates made from acrylic.  I had all sorts of problems and false starts making this jig, but in the end I was ready to do the cuts. Here I’m ready to cut the mortise into the guitar.

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And this is what the body mortise looks like.  Maybe you can appreciate how terrifying this cut could be. Not a lot of margin for error here.

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And here’s the tenon freshly cut into the neck heel:

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The holes in the heel are for barrel bolts which I’ll eventually use to screw the neck on.  Finding a source for these was a project into itself!

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This takes us to the middle of February.  At this point Mopus has a rough neck, a pretty complete body, and a way to connect one to the other.  That’s really great and all (and believe me I was thrilled), but there’s still a lot left to do and tell.  Mopus still needs a fretboard, some frets, and oh yeah, a bridge before we’re even in the ballpark. As I write this, all those things are now done! Stay tuned for part two!