Sunday, June 28, 2009

Installing Fretboard Binding and Frets

Sunday, June 28, 2009.

This week was dedicated to binding the fretboard and then installing the frets. I know it doesn’t sound like much, but these two steps took an unexpectedly long time (true for a novice like me, I am sure, less I suspect once you have done it a few times).

After having completed cutting my fret slots, my next step was to bend and install the binding on the fretboard. The binding I bought is a white plastic strip that measures .060" thick x .250" wide. Being stiff and relatively brittle, the first step is to shape it to the contours of the fretboard and then glue it in place. Shaping is done with heat and the recommended glue to attach it to the ebony fretboard is weld-on cement.

During my research, I read several stories by folks who, using heat-guns to shape their binding, had overheated it and “turned it to ash”. This is good to know since I already have a heat-gun and it is the method I chose to use. Other heating methods include boiling water and hot sand or glass beads and I will probably try the boiling water method when it comes time to shape the binding for the body, but for this, I used the heat gun.

At the base of the fretboard there are several relatively sharp curves around which I needed to be quite sure that my bends were accurate, especially with respect to each other. To accomplish this, I made a small jig out of some scrap wood and drill bits.

To make this, I traced the outline of my fretboard onto the wood and then found appropriately sized drill bits that roughly matched the inside diameter of each of the bends. As you can see, I drilled the holes and then used the bits themselves as my “posts” to bend the binding around (these photos are of my first attempt at this jig where I tried to use a rod in one location rather than a drill bit - it didn’t work out so well, so I ended up making another jig). By holding the binding between the bits and then carefully applying heat, it was pretty easy to get the curves where I needed them.

Because I have a sharp corner at the base of the fretboard, I made my binding from two pieces. If you have a different contour for yours, you might want to make this from a single piece of binding. Using weld-on cement from Stew-Mac, I glued my first piece to the fretboard and held it with a combination of spring clamps and C-clamps.

Gluing turned out to be a less than perfect operation. It seems that the cement needs to be applied relatively heavy and then dries pretty quickly. I did not expect this and was not as speedy when applying my clamps as I should have. Consequently I ended up having to re-glue several places. Once I did, though, it seems to hold well.

In the second photo above, you can also see a shiny spot where the glue got on the surface of the fretboard. When this happened, I was worried that it might damage the wood or cause a stain but this turns out to not be the case. Once everything dried (24 hours) and I scraped the binding down to the thickness of the fretboard, the glue scraped right off.

Time to install the frets.

Fretwire seems to come generally in two forms - long rolls and short, straight sections. If you are a serious builder looking to make many instruments, it probably makes sense to buy your fretwire in bulk, or roll form. If you are only making one or two, like me right now, it makes sense to buy just what you need. So I bought two lengths of straight sections.

Now one of the things I read, written repeatedly by various luthiers, is that it is best to curve or arch the fret wire a little bit so that when installing it, the ends make contact before the center. This is to prevent the ends from popping out again after they are installed. Apparently this is relatively common when the wire is not arched but not so much if it is. So, wanting to do this, I looked for a way to do it. As it turns out, you can bend it by hand (the method I ended up using), cut a groove in your workbench and pull the wire through it (similar to the method you might use to curl strips of paper by pulling them down across the edge of a table), or build/buy a bending device from one of the luthier supply houses. Bending by hand, while being pretty easy, was also pretty inconsistent, but I think it worked out well enough for me.

Once I had a gentle curve in the wire, it was time to cut to length. The method I ended up using for the majority of my wires was to hold the wire against the fretboard and, using a standard set of side cutters, cut the wire as closely as possible to the edge of the fretboard. This method allows the wires to hang most of the way over the binding when installed.

Obviously, since the binding itself does not have slots cut in it, I needed to trim the “tang” on the wire at both ends. To do this, I used a grinding disk on my Dremel to cut away about 1/8” of the tang.

Then it was a simple case of hammering the frets into the slots on the fretboard. For this I used a hard plastic mallet while holding the fretboard back against the anvil section of my vice. To aid with the ends-before-center idea of the curved fretwire, I tapped in both ends first before tapping in the center. Here is what it looked like after installing the first three frets.

I don’t really like the look of the first two fret wires so I decided going to replace them but figured I better wait until all the other frets were installed before doing that.

Here it is after all the wires were installed. I do have some extra wire left so I will be replacing those first two frets.

And, finally, here is what I did toward making the fretboard extension. It is made from a scrap piece of maple and will be attached at the base of the neck under the fretboard for extra support.

As you can see from this picture, something is not quite right. I suspect that the soundboard is too thick right below where the extension makes contact so my current thought is to scrape and sand it lower and then, where needed, trim the extension to match.

With the fretboard laying on the neck and the nut (yet to be shaped) in place for spacing, it looks and feels pretty good. It even appears that the 15th fret is pretty much aligned with the break line where the neck and body meet as it should.

As I looked at this side view for the first time, I was concerned with the gap between the neck and the back of the fretboard. Having laid the two together before, I did not find the gap then, but now I do. Then it occurred to me - the difference is the frets. With them installed, there are 30 small “wedges” forcing the top surface apart and, therefore, causing it to bow. Once I have it glued on the neck and fretboard extension, this should straighten right out. It also lets me know that I don’t want to do any form of fret leveling until then, either.

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