Leveling - techniques for protecting some regions while focusing on others?

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by UsableThought, Jan 7, 2018.


  1. UsableThought

    UsableThought Supporting Member

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    Here's my question: What techniques do folks here use for fret leveling a guitar that's already been leveled at least once, and you want to protect and/or avoid areas that don't need material removed, or when you will be making more than one pass to handle different regions separately?

    Reason I ask is, I'm about to do a second level and crown on an Epiphone Dot, based on a lot more experience than the first time I did it a year or two ago. Since I'm an amateur, I take care and go slow & use proper tools. Members whose comments on leveling I've read and found helpful include Walter W., David Collins, and John Coloccia, among others.

    This isn't going to be a spot leveling of a few high frets here and there, but rather, a general refinement. I plan on removing almost no material from most of the frets in first position; a small amount (under 0.003") from the 1st fret and also from a small "hill" of frets in the middle of the board; and very little from the tongue, with nothing at all from the last 3 or 4 frets. Why these imperfections exist is that first time around, I did the job without a neck jig - only to discover that the neck buckles slightly under string tension. Not a big deal; but now I have a neck jig, and although jigs are necessarily imperfect, it will give me a leg up in smoothing out the buckle. (As an aside, I totally agree with what David Collins has said elsewhere about the surprising non-rigidity of jigs - they can't be trusted blindly, you must watch for neck & beam deflection & compensate as best you can.)

    So you can see that I have some regions that will be getting more attention than others. Hence my question; in performing this second and more refined leveling, I hope to remove as little material as necessary and not just heedlessly grind.

    Here's the only example of such a technique that I've come across so far - at least I think it's an example; it's from a comment by @John Coloccia, in a 2013 thread titled "Adding "falloff" to upper frets? How?". John says the following:

    I can't tell from the above whether the masking tape is on top of the 8th fret, or on each side; I would assume the latter, except that "Acoustics need a bit more, so it gets more and I use a little more tape" seems almost to suggest it's on top - probably I'm misreading. I'd like to hear more; does anyone else here do something like this?

    Aside from that, I've read many descriptions by @David Collins here and on other forums of how he levels via a succession of passes, refining what has gone before. So again, I'm curious as to how he manages to protect areas that don't need leveling during a given pass; is it all to do with well-drilled motor skills & a detailed mental picture, plus appropriate beam/file lengths, plus left-hand support? Or do tape or other devices sometimes play a part?

    I wonder if a very thin-gauge brass strip, well-taped down so as not to catch its edges, might be useful over a fret that serves as a "pivot"? (Either that or just several layers of very smoothly-applied tape.) This would be useful only with leveling beams & sandpaper, not fret files: the idea would be that the region on one side of the pivot fret gets worked on, while the region on the other side isn't touched because of the way the pivot fret causes the beam to ride up at a slant. (Similar to what I asked about above w/ John C's quote.) The leveling beam, unlike a fret file, could also have an end free of sandpaper; this would be the end that travels over the pivot fret. Care would need to be taken with the depth of the sandpaper & the depth of the brass strip or tape, as well as frequent stopping to re-check or re-measure, re-marker frets, etc.

    Of course there is always using short strokes plus short leveling beam, e.g. I can use an 8" beam for one region in particular; this seems to be the technique that people mention most often for fallaway, for example; but I don't know if it's as useful for other regions of the neck?

    Anyone who's got experience with selective leveling, and favors a particular technique, please share!
     
    Last edited: Jan 7, 2018
  2. bob-i

    bob-i Member

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    If you have one or two frets that are high, spot leveling works. More than that, do the entire fretboard. From your description it seems you need a full level.
     
  3. Ayrton

    Ayrton Member

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    If I am just needing to kiss the tops of the frets, I use the Katana. Everything else goes into my Stew Mac neck jig.
     
  4. UsableThought

    UsableThought Supporting Member

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    Sounds like the title may have given a wrong impression about the nature of my question. I've edited it and also the first paragraph to remove references to spot leveling. It's more to do with minimizing removal of more material than necessary on frets that still have decent height, but aren't brand new anymore; plus maybe also where the neck is soft and will deflect very easily (despite the jig) if care is not taken. I hope that makes it clearer.

    Another way to think of it: Go read the other thread I quoted from, "Adding "falloff" to upper frets? How?," and look at the different ways that people create fallaway (if they believe in doing so) - it's not spot leveling, and it's not a full level either; it's selective. Essentially I'm asking about those kinds of techniques, but used elsewhere than the tongue.
     
    Last edited: Jan 7, 2018
  5. Jack Daniels

    Jack Daniels Supporting Member

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    Spot leveling is used if you have just a fret or two buzzing.

    If you want to take small amounts off the top of all the frets, you still work it the same as always...just use a finer grit paper or file. If you use 600 grit wet dry paper, it takes very little with each swipe. This allows you to watch all the frets lower until you hit the lowest fret on the board. It also minimizes the scratches you have to remove on the next steps. Otherwise, you do this job just like any other fret leveling job and work through the process.
     
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  6. UsableThought

    UsableThought Supporting Member

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    Sure, except that's not what I want. Sometimes that's fine - just-installed frets, etc. - but with your philosophy of "work it the same as always" you are ceding control to a full-length sanding beam without examining its path of travel. All paths aren't the same.

    Think about how a Plek works. Or just look again at the analogy to fallaway. Imagine if your goal wasn't to sand all frets equally - just letting a full-length sanding beam do its thing - but differentially. In this case, for example, I don't want to touch the last few frets on the tongue at all - the frets there & elsewhere on the tongue are shorter because the first time around I had to counteract a tongue rise (factory guitar). But I do want to bring the rest of the frets into a straight line, smoothing out the existing 0.002" buckling in first position. So the situation is similar to adding fallaway, except the direction is flipped. How would you do that?
     
    Last edited: Jan 8, 2018
  7. UsableThought

    UsableThought Supporting Member

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    Just to follow up, I did a search that came up with a David Collins comment over on Frets.Net (fretsnetning.com) where he describes his leveling techniques in detail, including how he takes more or less material off, adds fallaway, etc. The thread is titled simply "Plek"; link is here and link to David's comment is here.

    I could never hope to learn such a dizzying level of technique in a million years; but the fact that David (and I'm sure others) take the extra care and time they do is reassuring to me - I am not crazy to consider the sorts of possibilities I have raised in my post. Below I quote two highlights that seem especially germane; for full context, you can read that entire thread. I have bolded the stuff that jumps out at me for really being versatile.

    First highlight:

    My process starts usually with a bar just longer than the entire board with 220 grit paper. This is the first referencing stage to see how good or bad it is. From here I can adjust the truss rod to strategically minimize material removal, go to a heavier grit or bring in the files if much material needs to be removed from any area, or file/level away a rise in the extension to get it out of the way before starting the true leveling of the main section, etc.​

    Second highlight:

    Now there are a number of other little details to the process. Leveling in fall away at the extension is of course quite simple. For very minor fall away I may use a long bar, 15-18", with one or two pieces of tape at one end to create a very shallow angle. Mark the frets, and level until they are touching the area you wish for the fall away to begin. For more dramatic fall away I can use a shorter bar, more layers of tape at the end, or both. This can be done early or late in the leveling job, though I usually prefer to start it off early.​

    The tape idea he mentions here is what I was wondering about with John C's mention of tape in my initial post. Creating a shallow angle with tape is exactly what I am thinking of doing for the Dot.
     
    Last edited: Jan 8, 2018
  8. John Coloccia

    John Coloccia Cold Supporting Member Gold Supporting Member

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    It's on top. I think you got it already, but the idea is to force a slight angle into the upper frets. You can also do it with a short leveling block with varying strokes/pressure. Personally, I prefer no fall away and a straight neck. Just remember that the fall away is only there because the relief is there. If your neck is straight, you don't need fall away.
     
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  9. Timtam

    Timtam Member

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    Taping for fallaway from about 13:50 here ...
     
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  10. UsableThought

    UsableThought Supporting Member

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    Excellent, thanks for finding & sharing this.
     
  11. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    Have a short sanding tool handy for any fall-away follies. I use a 3/8thick piece of plexiglass 4.5" x 1.5" with a little handle on top. Lap the sole until it is perfectly flat and straight. Then use Loctite general purpose spray adhesive to glue 220 on it and there you go. Be sure to preserve the radius as you work.
    BTW much of the fall-away work is due to that COS bend at the body joint area. This is best dealt with via the fretboard surface/refret.
     
  12. John Coloccia

    John Coloccia Cold Supporting Member Gold Supporting Member

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    I always meant to ask you because I think you like straight necks too. Do you put any fall-away into new guitars? I tended to leave mine dead flat.
     
  13. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    Nice to hear from you John! No...I do not put fall-away into new TCM guitars, since the design eliminates the COS curve, and the way that the neck reacts to load is pre-determined.
     
  14. walterw

    walterw Gold Supporting Member

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    you have it backwards here.

    if the idea is to just knock down the "hills" while leaving the "valleys" untouched, then the full-length beam with the neck in the jig is exactly what you want. anything shorter and you will be hitting those shorter frets you're trying to avoid.

    +1 to @Jack Daniels' ("daniels's"? i never get that right) point about using a fairly fine grit on said sanding beam so as to take off material slowly and leave finer scratches when you're done.

    +1 also to @David Collins'es (goddammit) point about the flexibility of jigs, and wow what a next-level discussion that turned into :eek:; i'm just using a wooden jig, and after all the strapping down and pushing and pulling i've drifted into trusting what my eyes and the straightedges are telling me about the resulting profile more than what the dial indicators say.

    frankly though, the kind of esoterica in that frets.net thread might be more than you need to worry about as a "hobbyist" or as a player just trying to get your own stuff to play right. just the fact that you're using a jig and paying attention to what happens, enough to start seeing just how fussy and imprecise it all is, that alone puts you way ahead of a lot of people who work on guitars!

    as for fallaway, on electrics my own default is to do nothing more than a few extra swipes with a shorter file up top once the overall leveling is done, laying it flat but adding a little "english" like past the 18th fret on the treble side and coming back to maybe the 16th or 17th on the bass side (i.e., where nobody plays). using even thin tape over a lower fret to force the file to angle down would be much too dramatic for me.

    when done, if i were to re-blue the fret tops and do one pass with the flat beam it would still remove marker from those top frets, just not as much as the rest.
     
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  15. Jack Daniels

    Jack Daniels Supporting Member

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    This /\
     
  16. walterw

    walterw Gold Supporting Member

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    tell us about that thing.

    a neat idea, you leave the guitar strung up so the tension actually is "real world" and it slips under the strings to do the leveling.

    how flexible is it (being as thin as it is), and do you mess with the idea of introducing curve into the tool itself? that's the part i can't get past, it assumes that a neck relief profile is a perfect arc of a circle (the only way one curve can slide along another and keep contact along the entire surface) and i don't think that's true, it might be some sort of ellipse that's flatter in some areas and more curved in others.
     
  17. Ayrton

    Ayrton Member

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    The same idea as a neck jig, but more fine tuning than serious leveling.

    A piece of aluminum with a truss rod in it. Works great for fine tuning new frets or a new(ish) guitar.

    The little triangle don’t really help me because I like a flatter neck, so I just mark the frets and tweak the bar until I am touching all frets.

    Serious leveling of the frets or board and I use the neck jig.

    I thought it was worth the money as a home user, so I would thnk it would be a time saver in a busy shop.

    Sully turned me onto it

     
  18. Timtam

    Timtam Member

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    Some people have made one from a Martin-style truss rod ....
    http://www.stewmac.com/Materials_an...djustable_Truss_Rods/U-channel_Truss_Rod.html
    And something like brass capped nuts for the 3 fulcrums to get/set the bend.

    But yes ... a tensioned neck is approximated by a simple 3-point curve, which is then imposed on all the frets under it, with typically quite short sweeps of the 'curve'. But some people swear by them and get low action. So somehow they mostly seem to work OK.
     
  19. UsableThought

    UsableThought Supporting Member

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    Walter, from what you say here I'm pretty sure you're misunderstanding me - I am not about to use short beams on this neck. I'm sorry if I wasn't clear - my intent was to stick to my question about technique and not get sidetracked. But let me see if I can be clear at least about this one particular aspect.

    I don't want to repeat what David Collins has said so much better than I could about neck jigs & their limitations, but I will only say that I couldn't do what I'm doing to do without the neck jig. It has several great attributes. First and foremost, with the pushup & pulldown plus the depth gauges, I can very quickly get within the neighborhood of simulating of how the neck buckles under string tension; the gauges make setting up this simulation much quicker, although thereafter I double-check and refine by comparing to very careful chart of feeler gauge measurements (made with the jig's help in terms of avoiding deflection while measuring).

    What the gauges are especially great for is picking up neck deflection during the leveling process, something that can and does happen on many necks despite the metal support rods. As David has said, this feature alone makes the jig a great tool for learning. Being able to see deflection in real time allows me to compensate the right amount, when otherwise I'd be flying blind.

    As for a full length beam - as I say, I will indeed be using one; and, at the same time I will be using a modified version of the "tape" trick. Fret 20 will act as a pivot, so that the range of valleys and hills that the beam acts on is limited to frets 1–19, with frets 20-22 remaining unchanged. The maximum amount removed from any of frets 1-19 will be roughly 0.003". Frets 20-22 will have a very slight amount of fallaway - e.g. for fret 22 it will be about a half-thousandth. I'm staying off those frets because they're a little shorter - I had to bring the entire tongue down in the first pass due to a rise, apparently not an uncommon thing in a factory built guitar. So basically I'm creating a slight slant to how I level most of the neck.

    By the way I can imagine plenty of ways a neck jig and full length beam could be mis-used, if the assumption is taken too literally that "all you need to do is zero the gauges & apply a full-length beam and you're good." Here's one: Say you've got a neck as straight as you can get it, and the result leaves a significant hump or hill in the middle of the board - fairly broad as well as high. The hill will naturally cause a full length beam to rock very slightly; which means that if you don't think about what it is you want to do, and just leave it up to the beam, it will settle on one end and the hill peak, or else on the other end and the hill peak; and it will level that side of the hill first, removing more material there. That might or might not be what you want, if you're working with frets that are no longer as tall as they initially were (a guitar that has worn frets, or had at least one fret job previously, say). Again, it's a hypothetical, and it may not come up very often, or be significant when it does. But probably there will be situations in this level of thinking and planning can be beneficial.
     
    Last edited: Jan 9, 2018
  20. walterw

    walterw Gold Supporting Member

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    that won't work.

    you'll just create a fallaway at the nut end, which you very much do not want.

    just adjust the neck as straight as it will go (equally over and under-bowed, so you're not taking too much from any one spot), lock it into the jig, and flatten the fret top profile with the long beam. if the last few frets are indeed already low then the beam won't touch them, and if they're actually high then the beam will knock them down level with the rest, that's the whole idea.
     

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