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Crowning frets question

Discussion in 'The DIY Tool Shed' started by trxx, Oct 22, 2020.

  1. trxx

    trxx Tele-Afflicted

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    I did a level and crown once using pretty crude tools (many years ago). The results were less than stellar. One issue I had, and maybe it was the lighting, was in knowing when a fret is really properly rounded over or if the sharpy line has just been scratched off. I mean, if that fat sharpy line is just touched with a file, the sharpy in that area is removed, but that doesn't mean that the area has been properly profiled to the line. I guess one way to approach that would be to start at the top, filing something of an angle to the sharpy line, then profile toward the bottom. This seems to be the opposite of what I see everyone doing though.
     
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  2. Laren

    Laren Tele-Meister

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    I found this video is about the best I've found on the topic. Plus the one that proceeds it.



    Hope it helps.
     
  3. Freeman Keller

    Freeman Keller Friend of Leo's

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    The way I do it is very simple. I make the fretboard as flat and true as I can before I start, that way the leveling only takes the minimum off any frets. After fretting I again make sure the frets themself are as level as possible - check between the board and fret crown with a very thin feeler to make sure they are down tight. In other words a good fret job should require minimum leveling.

    I sharpie every fret. I level with a 24 inch beam with 400 grit. Ideally every fret will still be colored but will have a tiny shiny line on the very crown. Obviously that doesn't always happen but that is the goal. I don't "round over" the tops of the frets, I actually flatten them (it has been called the "school bus shape").

    Once they are all level I hit the crowns again with the sharpie and start putting the curve back in. Here, ideally, all the sharpie color will be removed except a very fine line right across the very top. In other words I don't want to make them any lower, just rounded. Once I'm happy with that I'll do the final polish, which removes that line of sharpie color and any scratches
     
  4. trxx

    trxx Tele-Afflicted

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    Maybe I didn't explain myself well enough in my question?
     
  5. SRHmusic

    SRHmusic Tele-Meister Silver Supporter

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    I bought a StewMac crowning file, not the most expensive, but with the handle and 300 and 150 grit on the two ends of the shaft you can pop out and turn around. It works reasonably well, and then it's lots of polishing with their fret erasers 600, 800 and 1200, and micromesh papers if I want to really make them mirror smooth. I've switched to stainless steel frets on all my main guitars so only some touch up is needed these days and the same tools still work fine. Good lighting is key, and I, too, find the marker approach is good for leveling but not as much for crowning. Sometimes it works just right and you can see a thin line down the center. Not sure what type of marker is best.

    Before crowning files, I think the good luthiers would do the crowning by hand with a small flat or triangle file, and perhaps one with a flat milled edge to minimize the chance of scratching the fingerboard. And some probably still do it this way.
     
    Last edited: Oct 22, 2020
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  6. TwangBrain

    TwangBrain Tele-Meister

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    Well, the only advice I can give is to not rush. Be methodical and exercise patience. Getting a rounded crown after leveling is either a chore w/ common tools, or you can make/buy a file with a curve. A gouged concave sliver of hardwood with some fine-grit paper will get you a rounded profile. Then simply refine with finer grades and buff with steel wool or abrasive buffing pads. Tedious either way you do it...the reason why those jobs can be pricey when taken to techs and luthiers.
     
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  7. ritten70

    ritten70 TDPRI Member

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    I’ve never seen it done from the top down but can’t think of a reason it wouldn’t work. I generally use a triangle file from the side and sneak up to leave about 1/32” of sharpie. After I have that I sand up to about 1500 grit before hitting it with polish to get the crown. As I’m going I use a fret rocker, especially if I do kiss the top and the sharpie lines disappear. So, to answer the question, I use a fret rocker as I go.
     
  8. trxx

    trxx Tele-Afflicted

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    I asked the question in the original post because it seems that without first starting by establishing a thinner top sharpy line after leveling it would be more difficult to judge whether any profile filing has merely knocked off the sharpie (without any significant profiling) rather than having really began a profile from the desired top line. I mean, something that might better demonstrate this point would be using a cloth to carefully wipe away all the sharpie except for the top desired line width, where nothing has been removed from the fret. I'm thinking that the same could happen using a file, lighting passing over the fret, removing all sharpy except for the desired top line, but nothing has been really profiled.

    Hopefully the better explains what I mean for others who are replying. I'm pretty sure you already know what I mean to say here.
     
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  9. ritten70

    ritten70 TDPRI Member

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    Gotcha, think that would work fine. Lots of different roads get to the same destination. I actually might give that a try on my next fret job. It actually might be a way to provide a more consistent fret top.
     
  10. PhredE

    PhredE Tele-Holic

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    trxx,

    Ron Kirn has a pretty good tutorial in the TDPRI DIY section -- it's got some good pics in there too. It's very similar to Freeman's approach and vice versa.

    Edit: As someone mentioned above, I find I do a lot better job in sunlight and even better when I can magnify those frets and look close/hard at each one.
     
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  11. trxx

    trxx Tele-Afflicted

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    Both of those sound like a good idea. Thanks.
     
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  12. trxx

    trxx Tele-Afflicted

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    I'm thinking that it might result in less work. If just enough angle is established either side of the flattened fret top to thin the flat, then it seems it would probably require less profiling. I'm just drawing it out and thinking about it, and will have to put it to the test I suppose. So I guess it's a matter of figuring out how little angle is required approaching either side of the flat to prevent fret buzz. I have a badly worn neck here that I can experiment with to find out.

    A simple illustration of what I mean:

    [​IMG]
     
    Last edited: Oct 22, 2020
  13. trxx

    trxx Tele-Afflicted

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    I'm also thinking here (maybe the whole idea is naive) that a very simple tool could be fashioned that rides on top of other frets, having the needed angle over the fret of interest (whatever that angle turns out to be) with sandpaper stuck to the tool. I think this isn't hard to imagine, but I'll have to wait until tomorrow to draw up a simple illustration.
     
  14. trxx

    trxx Tele-Afflicted

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    When I think it over, a tangent line along the circumference of a circle has an infinitely small approach angle to a given point (think fret top). So if a truly round fret top were ok, a very small amount of approaching angle should be fine. Maybe 5-10 degrees for safety against buzz?
     
  15. gregulator450

    gregulator450 Tele-Afflicted Silver Supporter

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    Is there a specific crown shape you're going for?

    I have both a Stew-Mac two-sided diamond crowning file made for medium and wide frets (pre Z-file), and a three-corner slim taper file that I modified myself for safe edges. I can't really tell a difference in crown shape using one or the other on the same size fret. I always start at the base/bottom of the fret and work my way to the crown. I would probably create extra work for myself if I started at the top. When I 'roll' the file (slim taper) toward the crown, it should create a good rounded crown profile. From a more philosophical standpoint, I would think that "just scratching off the sharpie" on my way to the center of the fret top would be the ideal situation for a crown. I like to remove the minimum amount of material as possible when doing fretwork, and the subsequent smoothing and polishing should further refine the crown to its best shape. I might add also that the height and width of the fret wire will have some effect on the crown shape, whether you have the school bus fret shape or a more rounded and vertical fret shape in the end.
     
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  16. Freeman Keller

    Freeman Keller Friend of Leo's

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    If you use a crowing file with a radius very slightly larger than that of your fret you automatically do what you describe in your diagram. At least that is always what I assumed I was doing by watching the sharpie color go away.

    I've honestly never tried to master crowning frets with a three sided file. I use jewelers files for the facets on the ends and a set of standard fret crowning files for the crowns. I will often put a piece of sand paper in the notch of the file but that is after I've got the rounded shape re-established.
     
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  17. schmee

    schmee Doctor of Teleocity Silver Supporter

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    I have fret crowning files for taking the flat off. 3 sizes. They are curved cross section.
    My final though is just 600 wet sand paper run lightly along the length and the fret crown.
    Then a Dremel and 3M Finesse It with a cotton wheel and you can see your reflection in it in seconds!
     
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  18. jrblue

    jrblue Friend of Leo's

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    Anything that knocks off the top sharpie line is a mistake -- a serious one, in fact. If this commonly occurs, you need to practice until it doesn't. Most people start fropm the bottom up in order to minimize the change of marring the crown, but I would thinbk whatever you can actually control would be the method to use. I can fret quite well, but do not do it nearly enough to use some of the filing techniques that people who do tons of fretwork can control, so I use a crowning file, which with its concave shape pretty much eliminates the possibility of messing up a fret top.
     
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  19. Freeman Keller

    Freeman Keller Friend of Leo's

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    Be careful with a dremel. If the frets have been installed with glue the heat will release it and if there is any binding the heat can either damage it or release the adhesive. A slip with a dremel can do some quick damage to the fretboard

    I agree totally and that is what I was trying to describe in my post. When I am done recrowning I want to see the thinnest line of sharpie right on the very crest of the each fret. Polishing will take that off but no more material.
     
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  20. schmee

    schmee Doctor of Teleocity Silver Supporter

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    I hear you, actually with the damp cotton wheel and Finesse it, you hit each fret for literally about 10 seconds! No heat at all.
     
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