Zero fret with Fret Scale Template.....How???

Discussion in 'Luthier's Corner' started by honza992, Jun 2, 2018.

  1. Hi All

    A quick question, though hard to explain. I would like to use a zero fret but I can't quite work out how to do it in conjunction with a Fret Scale Template.

    I've checked with Stewmac and they confirm that their fret scale templates are designed to be used either with a Fender style nut or with a fretboard which is cut off at the nut. This is because the template takes into account the thickness of your saw blade when making the cut at the zero position. Using a zero fret though means that the theoretical zero point is not aligned with the top of the zero fret, it will half of 0.023" away from where it should be.

    Does that make sense?

    So does anyone know if I can use this sort of template with a zero fret, or would I have to cut the zero fret slot by hand?

  2. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yes, you are technically correct. If you cut the zero slot using their template, and then put a zero fret in it, the center of the crown of the zero fret will be about 0.010" too far away from the other frets.

    Two ways to fix this:

    Cut the zero slot. Then reposition the template 0.010" toward the headstock, and cut the rest of the slots.

    The easier way is to cut all of the slots as they are on the template. Then use a taller size wire for the zero fret. File the top surface down to the correct height (about 0.010" higher than the other frets), which leaves a fairly wide flat across the top. Then crown it asymetrically; round off the side toward the headstock more than the side toward the frets. File it so the edge that the string sees is even with the fingerboard-side of the fret tang.
    joselorellano and honza992 like this.
  3. That's great, thanks Bruce. Simple effective advice, as usual.
  4. rwkeating


    Oct 1, 2014
    @Bruce Johnson, you've mention this before (about making the 0 fret hire than the rest.) How would you do that? I know how to level all the frets, but I can't figure out how to do the zero fret on its own.
  5. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Do you mean how to measure it, or how to cut it to height?

    To measure the height of the zero fret in relation to the others, you need some kind of a straightedge or a metal bar about 6" long. First, lay the bar on a flat surface and use the depth rod on the end of your digital calipers to measure the height of the bar at the one end, that is, the height from the top surface of the bar down to the flat surface. Zero the calipers. Now, lay the bar on the frets, resting on frets 1-4, with the end coming up right against (but not on top of) the zero fret. Use the calipers' depth rod to measure down from the top of the bar to the top of the zero fret. The caliper will read out how much higher the zero fret is above the others. Is my description understandable? It's not as complicated as it sounds.

    Because I do this all the time, I built a simple gauge with a brass bar, a wood handle and a dial indicator. The bar rests on frets 1-4 and the indicator tip rests on the zero fret. The indicator is zeroed with the bar resting on a flat surface. Same idea, just faster. I check the zero fret height at each string position.

    To cut the zero fret higher than the others, there are several ways.

    One way is to start with all the frets the same wire size and height, then level all the rest of them down 0.010", leaving the zero fret untouched. That's what I do on most of my instruments these days. I do my leveling with a long sharpening stone. You may have seen my technique on other threads. Other folks use beams with sandpaper, or long flat fine files. Whatever your tool of choice, do the grinding/sanding/filing all the way up to, but not over, the zero fret. Keep checking the height of the zero fret above the others as you go. Get them all leveled and 0.010" below the zero fret. All in one operation. Crown and polish all the rest of them, and don't touch the zero fret.

    Another way is to use a different size, taller height fret wire for the zero fret. You can leave it out initially, if you like, while you level and crown all the other frets. Then install the zero fret and measure its height. Trim it down to the right height with a small flat file, checking the height as you go. When you get close, switch to a small sharpening stone, sliding side-to-side, to take out the file scratches. Then crown it and polish it.
    rwkeating likes this.
  6. rwkeating


    Oct 1, 2014
    Thanks for covering it all. I was referring to both the measurement and the cutting method.
  7. rudy4444


    Mar 13, 2012
    Central Illinois
    The latest edition of Taylor's Wood and Wire magazine has a reader's question about Taylor's nut position. Bob Taylor states that the nut is technically "too close" to the first fret, as they cut the boards on a gang saw and position the nut at the front edge of the slot where a "zero fret" would be located. Something to consider...

    My Taylors have the sweetest intonation of any of the guitar brands I've owned.
  8. That's really interesting, thanks for posting that.

    On a 34" bass the difference (half the saw kerf) is 0.0115" or .0.3mm. As a percentage of the string length thats 0.03%. My fret crowning ability probably has a margin of error not that much smaller than 0.3mm!

    Next build is zero fret time!
  9. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yeah, that's about it. While technically, the error is there, in practice it usually is corrected/offset by other things. For example, even if the front face of the nut is 0.0115" forward of the "0" line, when you file the nut slots, there will usually be a tiny bevel or radius at the front edge of the slot. This pushes the effective break point of the string back a tiny bit, in the direction that corrects it.

    As you probably have read, I have a special slotting machine, and I slot about hundred necks a year for my own basses and other Luthiers. I've worked this issue quite a bit. I make up my own slotting scales for my machine, and I make them all with the Zero line right on the zero position. That is, cutting a zero slot puts the zero fret in the right position in relation to the other frets. I use zero frets on all my own basses. But, most of the necks I slot for other guys use slot-style (Fender-style) or shelf-style (Gibson-style) nuts. When I do them, I make a slight correction of half the saw blade width when I'm zeroing my machine.

    What's the tolerance, in terms of dimensional accuracy of nut/fret position versus what you can hear and measure on an electronic tuner? In my experience, the (actual fulcrum break point at the) nut needs to be within +/- 0.005" of the correct position. If it's out more than that, you may not hear it, but you can see it on the tuner. As you move up the neck, the tolerance gets tighter. At the last fret, it's more like +/- 0.002".

    Fret position is the highest accuracy part of building instruments.
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