need advice on fret leveling a compound neck

[arjepsen]

Hey.
A few years ago, I built a strat: ash body with canary laminate, and a canary pro construction 59 roundback neck.
I've never been able to get the action as low as I felt should be possible, and so I've been working on trying to fret level it.
I have a straight edge from guitarsandwoods.com, and also a technofret advanced leveling system.
I tried leveling it first, using the same method I saw in videos on youtube (check smbstressfest and his work on a warmoth strat). However, after that it seemed that I had to actually raise the action / put in more relief to get rid of buzz :-(
So now I'll try just using the technofret under-string leveling beam.
However, I'm a bit unsure about the straightness of the neck.
I'm trying to level it out using the straightedge on 3 little metal standoffs, which I place at 2., 8. and 20. fret. This is where it gets a bit confusing.
Right now I have it straight down the center. However, I get a slight rock (back bow) when I measure down the sides on the fretboard (low and high E string).
Is this because it's a compound neck, or??

Regards
Anders

 

[john_p_wi]

Anders,

I have had better luck leveling the compound radius pro necks using a 6 inch dia sharp sharpening stone and going across, side to side of the neck after checking the straightness of neck using a notched straight edge.  IMHO and experience, the longer leveling beams moving in the direction of the length of the neck do not work as well as the smaller 6" dia sharp stone moving across the neck ON COMPOUND RADIUS necks.  The longer beams do not allow for the change in radius easily (think cone diameter).  The Katana and other "under string" systems make it difficult / prohibit the ability to follow the radius change as the strings limit the side movement of the leveling device.

John

 

[stratamania]

On the longer edges you need the edge to follow the line of the strings rather than parallel with the centre line.

If you are trying to set a straight edge at the edges of a compound neck parallel with the centre line it will rock as a compound radius is a cross section of a cone.

When levelling you also need to take that into account and follow the lines the strings would make as a guideline.

 

[arjepsen]

Anders,

I have had better luck leveling the compound radius pro necks using a 6 inch dia sharp sharpening stone and going across, side to side of the neck after checking the straightness of neck using a notched straight edge.  IMHO and experience, the longer leveling beams moving in the direction of the length of the neck do not work as well as the smaller 6" dia sharp stone moving across the neck ON COMPOUND RADIUS necks.  The longer beams do not allow for the change in radius easily (think cone diameter).  The Katana and other "under string" systems make it difficult / prohibit the ability to follow the radius change as the strings limit the side movement of the leveling device.

John

Well, this is where I'm a bit in doubt. Right now the neck (that is - the wood) is strung up and straight down the middle, but very slightly backbowed on the sides. (following the line of the string)
However the level of the frets themselves are slightly backbowed down the middle, but straight on the sides.... (following the line of the strings)
I do have a diamond sharpening stone, but how can I make sure that the frets are level over the entire board, when the neck shows the problems that I just described?
And...
Isn't the ideal, that the frets should be level in a straight line following the string - (also on a compound neck)?
Isn't that exactly what the technofret leveling beam would do - level the frets following line of the string instead of the line of the center?

 

[john_p_wi]

Without physically seeing the neck and without having a proper setup, it can be difficult to understand what is happening.  As previously mentioned, I always use a notched straight edge down the center of the neck to make sure the neck wood is straight.  One of the most difficult things to learn is to read the neck and to understand what is going on - especially the relationship between nut, neck radius and bridge.  Could it be that previous attempts to level the frets rendered them uneven in height from the edges to center?

In regards to the strings following the path of the compound or cone, it is not exact.  The bridge width / string spacing and the radius that the bridge is set to is a major factor of course.  If one does a quick back of the envelope math adventure, one will find out that the difference in spacing of the strings between the nut and bridge is around 0.5 degrees.  This does not sound like much, but when multiplied by the 5 spaces between strings over the length of 25.5 inch scale length it is fairly large - and does show that the strings are too narrow at the bridge to follow the "exact cone" and is why the under string leveling systems are inhibited by the string.  It is not possible to "fan" the leveling beam out at the bridge end far enough on compound radius necks to follow the theoretical path.

 

[arjepsen]

Hmm... I'm trying to get my head around this.
Isn't it always the goal to get the frets level underneath each string to combat buzz.
If they're not level, wouldn't they... like... buzz? ???
Not trying to discard what you wrote - just trying to get my head around it.

In any case:
The neck wood is straight down the center.
Frets are backbowed down the center, but level down the sides under the e-strings.

So my question is what I should aim for with the frets, and how best to do so.

 

[john_p_wi]

Yes, the frets need to be level - following the path of the string with a rigid leveling beam WILL change the compound radius if done improperly, which is why in first post I mentioned that the best success that I have had is going across the strings.  Generally, I need to raise the action above what could be the lowest playable action to allow a little more string height for bending - this is with 6100 SS frets too.  Warmoth's pro compound necks are capable of incredibly low action IF set up / leveled properly.  Don't forget, strings are flexible, rigid leveling beams are not - strings will find the contact point of the neck when pressed while rigid beams will change the radius on the neck IF done improperly.

Do you have any way to measure the fret height across the width of the neck?  It truly sounds if previous leveling attempts went south.  Again, has the nut / neck / bridge been set up properly?

IF you feel that you are in over your head, you could always have it Plek'd, take it to a pro, or simply buy another neck.

 

[arjepsen]

Yes, the frets need to be level - following the path of the string with a rigid leveling beam WILL change the compound radius if done improperly, which is why in first post I mentioned that the best success that I have had is going across the strings.  Generally, I need to raise the action above what could be the lowest playable action to allow a little more string height for bending - this is with 6100 SS frets too.  Warmoth's pro compound necks are capable of incredibly low action IF set up / leveled properly.  Don't forget, strings are flexible, rigid leveling beams are not - strings will find the contact point of the neck when pressed while rigid beams will change the radius on the neck IF done improperly.

Do you have any way to measure the fret height across the width of the neck?  It truly sounds if previous leveling attempts went south.  Again, has the nut / neck / bridge been set up properly?

IF you feel that you are in over your head, you could always have it Plek'd, take it to a pro, or simply buy another neck.

Well, I don't think I have a plek place anywhere near. (I live in Denmark, on zealand).
But also, I want to learn to do it myself. I already did a couple of practice runs on old strats.
But they didn't have the compound neck.
Anyway, yes, I do have a caliper. Just doing a quick measuering across the board shows generally around .047 on the edges, and around .052 in the center. Yes, it was just a fast measurement not truly precise, but are there anywhere in particular you want me to measure?

 

[Cagey]

Wow. .005" variation in fret height? That's huge. Your radius is already compromised. Somebody did some aggressive (and uneven) grinding. But, don't worry about that too much. You can usually compensate at the bridge.

Here's the thing. With a neck that's already fretted but where the frets are not destroyed from excessive wear, you don't really care where the fretboard is. You don't play the fretboard, you play the frets. They're what need to be level, not the 'board. If you're re-fretting, then you level the 'board. Otherwise, you can essentially ignore it.

That means a couple things. First, you need an accurate straightedge, not a slotted unit that ignores the frets. You also need some feeler gauges. That way, you can adjust the truss rod until the neck is straight relative to the frets.

Then, you use a fret rocker to find any frets that are a bit high. Mark them with a Sharpie or write on the masking tape or something. Then, use a crowning tool such as this...

... to lower those frets. Once you can't get a .001" feeler under any of the frets, then you dress and polish them. Once that's done, you put about .008" to .0012" relief in the neck, and you're good to go. Bolt it on the guitar, string it up, make any necessary bridge adjustments, and take over the world with your amazing wankitude.

If the whole thing is a hot mess, then the Diasharp files mentioned earlier will allow you to level en masse better than the "beam" solutions some subscribe to. To maintain radius, just keep track in your head how much time you're spending in the different areas. It's a feel thing. Check your results often, so you don't remove more material than you need to. If you can avoid that, though, you're better off. The thing to remember is that everything is relative. Also, be patient. It's a pain in the ass to keep measuring frequently, but it can save you having to re-fret, which is more like an ass beating.

 

[arjepsen]

Thanks.
I understand the point about the frets being more important than the wood.
But I just need to get one thing clear:
If I have the frets straight down the center - should they be backbowed down the sides, or?

 

[Cagey]

No. They should be straight everywhere.

 

[arjepsen]

Sorry, I'm getting confused.  :-\

Right now - if I adjust the trussrod so that the frets are level on the sides, then there is a backbow down the middle. So if I adjust the trussrod so that the frets are level in the center, they would have a relief on the sides.

If I understand you correctly, then they should be level (in line of the strings, right?) all the way down the neck, both center and sides.

That means that I would either have to take some material off the frets in the middle, down the center.
Or I would have to take off some material at both the nut and bridge end of the frets on the sides.
Am I correct, or have I misunderstood?

 

[stratamania]

I think you have understood correctly.

Which option of the two to choose would be the one that will remove the least amount of fret material.

 

[john_p_wi]

Sorry, I'm getting confused.  :-\

Right now - if I adjust the trussrod so that the frets are level on the sides, then there is a backbow down the middle. So if I adjust the trussrod so that the frets are level in the center, they would have a relief on the sides.

If I understand you correctly, then they should be level (in line of the strings, right?) all the way down the neck, both center and sides.

That means that I would either have to take some material off the frets in the middle, down the center.
Or I would have to take off some material at both the nut and bridge end of the frets on the sides.
Am I correct, or have I misunderstood?

Above, you mentioned that the center was .052 while the sides were .047 inch, - I would start in the center as there already is a 0.005 difference in fret height.  Mark the frets and go slow with a lot of measuring and marking in between.

 

[Cagey]

It sounds like someone used a radius block to level the frets at some point, not realizing the geometry of the neck. That would account for everything you're seeing.

 

[Dan025]

Hey.
A few years ago, I built a strat: ash body with canary laminate, and a canary pro construction 59 roundback neck.
I've never been able to get the action as low as I felt should be possible, and so I've been working on trying to fret level it.
I have a straight edge from guitarsandwoods.com, and also a technofret advanced leveling system.
I tried leveling it first, using the same method I saw in videos on youtube (check smbstressfest and his work on a warmoth strat). However, after that it seemed that I had to actually raise the action / put in more relief to get rid of buzz :-(
So now I'll try just using the technofret under-string leveling beam.
However, I'm a bit unsure about the straightness of the neck.
I'm trying to level it out using the straightedge on 3 little metal standoffs, which I place at 2., 8. and 20. fret. This is where it gets a bit confusing.
Right now I have it straight down the center. However, I get a slight rock (back bow) when I measure down the sides on the fretboard (low and high E string).
Is this because it's a compound neck, or??

Regards
Anders

ok, without giving too much input that may conflict with others advice i'll just explain the geometry here.

a compund neck is basically a section taken from a cone. the ideal geometry has the point of the cone directly under the point where the "E" strings would converge if it they were extended out far enough. the reason for a compund neck is that the strings and neck taper, therefore you need a surface that tapers. if you stretch a piece of string down a straight tube everything is fine as long as the string is parallel to the axis of the tube. if you stretch the string diagonally it will have to curve around the tube. the same goes for a cone section (like if the top was cut off) but if it were a full cone and one end of the string is anchored at the very point of the cone it's impossible to cross the axis of the cone and you will always wind up parallel to the surface with no curvature.

if you are leveling frets on a compound you should follow the string path and not stay parallel to the center line or you end up with a wierd contorted cone like shape that doesn't have the bennifits of a proper compound setup. the issues you may have are that the string spacing is not ideal to the fretboard geometry. if this is the case you could notice that even though you are following the string path you still get the appearance of back bow on the "E" strings.

if you have a tune-o-matic bridge (narrow spacing, fender had wider spacing) or a different nut width from what the compound was designed for (unfortunately they don't have a different compound for wider nut widths) or a vintage fender bridge which has even wider spacing than a modern "tremolo" style bridge you may notice a hump. i believe the "ideal" mix of spacing is a popular trem like a modern fender. not a floyd or vintage fender and either a 1-5/8 nut or 1-11/16 nut but i'm not sure which. it may be beneficial to use a wider nut or narrower bridge though, as if you do this bends will first bring the string closer to alignment with the point of the cone before you go over center and start getting back into a situation where there is a hump. this might get you a little extra bend.

if you level the neck with a straight edge you can get any hump out of the string path by following the string path. even on a non compund neck, you just end up with a weird, semi cylindrical shape that's pinched in in the middle like an hour glass but on a scale too small to see. well it would be more of an hour glass that was bent so that there would be one line that was straight.

edit:

now i see your hump is actually down the center?? odd! unless somone used a radius block wider than the nut radius and went most heavy on the nut end ie they used a block with some relief still set into the neck and the block matched the high frets in radius.. or your frets are just worn out by the nut from playing a lot in that half of the neck. there can also be wood shrinkage. it's always best to setup a guitar after it has a bit of age to it. you may set it up new but it will change, after some time things will kinda stabilize especially if the humidity it encounters is consistent. if i wanted to correct this i might split the relief you see on the edges and start with both backbow down the center and relief down the e strings. as long as you work in the direction of the strings you should come up with a good setup in the end.

if you really want to get down to the bottom of where the missing material is though, you might want to 1 check the wood not the fret tops. you could have frets that lost their seat lifting and skewing things. and also check the radius with radius gauges. if you found the nut radius to be larger than 10" then you would want to take most material off the tips of the frets on the nut end.

 

[arjepsen]

Thanks all for the answers... though I have to say I'm still in doubt about how to proceed.
I have two tools, that I could use for this job:
1: a straightedge/beam with sandpaper on - about 1½ cm wide. it's an angled thingie that can go under the strings, and level the frets while under string tension.
2: the diamond shapener stone.

I'm leaning towards the straightedge, since it's sure to level  the whole length, where the diamond stone is more difficult to use in getting the whole length straight/level.

Given the problems that I've described, which would you guys suggest?

 

[Cagey]

I'm not sure why you'd want to level the frets while under string tension. It doesn't get you anything, and adds a lot of hardship. Unclench $4 and buy another set of strings so you can sacrifice the ones on there. All this work is a LOT easier with the neck off the body.

For as uneven as it sounds like those frets are, you are certainly going to need a crowning file, no matter what you use to level the frets.

For what a good crowning file, a dressing file, and a set of abrasives to smooth/polish out the frets after you're done grinding on them, you might be able to buy a new neck. I know you want to learn how to do this. I've been there. I bought the tools. But, I also knew I was going to use them repeatedly over time, which is what it takes to justify the expense. If this is a one-off, that may not be the best way to go.

You might want to consider using this one as a slide neck, or selling it to someone who's looking for such a thing. In that case, the frets don't matter so much. Then, get a new neck that doesn't need such a drastic amount of work.

 

[arjepsen]

As far as I've understood, the neck will have a slightly different shape under tension, than with the strings off. That's the reason for trying to level them under tension.

 

[john_p_wi]

Cagey, The idea behind the under string leveling with the neck under tension arises from the idea that some necks only develop humps etc while under string tension in which the leveling bar would eliminate.

arjepsen, Cagey's advice above is very good.  Personally I think using the 6" dia sharp and going across the frets in the center area of the neck would be your best solution, not working the edges which are already lower.  Going across the neck would help maintain the radius while lowering the center of frets.  This is why you will need to measure and mark repeatedly. Trust me, the fret material will be removed much quicker than you think.  Additionally, make sure the neck is supported under the area that you are working.  Also it does not take much downward pressure on the tool to remove material, generally the weight of the stone is enough.

Would using the narrow leveling beam under the strings simply add facets or flat spots under the strings?  It seems as though the strings would interfere with the side to side movement of the leveling beam and as I said above, the string path does not follow the cone exactly - do the math.

Go slow and good luck.