A question about frets, fretting, neck backbow

I have been using fretwire from StewMac, as well as their circular saw blade for cutting fret slots. I use an arbor press for setting the frets. After fretting a board, it takes an arc shape, from the compression added from the fret tangs. Seems normal. I did one in Snakewood, which is quite a bit harder than ebony, and as expected, the arc was more severe. As I glue the fretboards to the neck after they are fretted, I have not seen a problem with neck backbow. Maybe just a little issue with the fretboard 'diving' where the neck ends. I have been putting in a stiffer upper transverse brace to counter this.

No real problems... that I am aware of...

I am now about to build a couple electric guitars, and a bass, some people fret after the finger board is installed with these. With the increased number of frets, that could cause a problem. I have researched on the net, and see that other people have experienced issues with this. Some have mentioned that the Stew Mac blade might be too thin for the Stew Mac (Duncan) fretwire.

Any thoughts on this?

I just read a thread where the slots were cut to thin for the frets causing the neck to bow...and the uke to buzz...
and learned about neck relief on the same thread....

try searching "neck relief" on the UU and maybe It will help you understand...

hawaii 50 said:

I just read a thread where the slots were cut to thin for the frets causing the neck to bow...and the uke to buzz...
and learned about neck relief on the same thread....

try searching "neck relief" on the UU and maybe It will help you understand...

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I think that thread you are referring to is bogus. I've never had a neck distort because the fret board had a little bow in it before it was glued to the neck.
How thick are you fret boards anyway? They should be somewhat flexible unless they are overly thick.
BTW! If you bind the fret board it will remain straight after fretting.

I think neck relief is a different issue. That would be a Band-Aid ( for a broken bone) to engineer that in to deal with a back bowed neck. I was under the impression that neck relief is so the shape of the top of the frets more closely matches the shape of an oscillating string, which on an uke seems more theoretical (in actuality, and relief really required) than on a longer scaled instrument. On a longer scaled instrument and chasing low action, I can see how relief can be important(but still subtle). I do not fully understand all of this yet. On ukes, I have not seen a backbowed neck. I am concerned that if fretting a longer neck with the board in place, that it may bow.

I am looking at that snakewood fingerboard now, it is less than 1/4" thick at the crown (significantly) (it is also radiused) Without calipers, I am guessing 4mm at the crown, maybe 4.5? It is bound, and it definitely did not remain flat after fretting. I like bound fretboards, have done a few. Compression from frets did leave them so they were not flat after fretting. The Ebony boards I have built required little pressure to flatten out so not an issue, more of an issue of just making sure that the upper brace was stiff enough, and not worrying if it dives slightly there. I have only been playing for less than a year now, and am not yet shredding beyond the 12th fret. Maybe next week though...

Words that I found on the net that most concerned me are that perhaps the StewMac saw blade is designed a little thin for their wire? Doesn't seem like that could be, as it would be too easy to fix.

Currently I have had no issues, other than I noticed that the Snakewood board definitely took a little more pressure to flatten out, but I have not built a long guitar neck yet.. Trying to avoid problems before they happen.

Maybe people were having problems from improper clamping and/or, using water based glue?

Its no problem on guitar fretboards. I get some bow when the frets are in but not more than a ukulele. There are more frets but they're farther apart and the board is a bit thicker. I haven't measured it, but it only takes a few pounds of pressure to flatten it out...a one finger amount of pressure.

I am concerned that if fretting a longer neck with the board in place, that it may bow.

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Isn't that what truss rods are for? To adjust for any change in neck angle, mainly due to string tension but it could also address any relatively minor pressures exerted by a bowed fretboard.

Maybe your snakewood fret board is too thick too flatten out. Personally, I think any fretboard approaching 1/4" is far too thick. I aim for somewhere between 3.5 and 4mm. My #764 wire goes in easily but snugly when slotted with the StewMac blade. I wouldn't want the kerf any wider. The caul I use when gluing the fret board to the neck also has matching relief.

mzuch said:

Isn't that what truss rods are for? To adjust for any change in neck angle, mainly due to string tension but it could also address any relatively minor pressures exerted by a bowed fretboard.

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Good point. I don't use adjustable truss rods (most ukulele builders don't) but I do use a carbon fiber reinforcement rod laid into the neck. Once that is set in the neck's not going anywhere.

I use CF in my uke necks, a 1/2" x 1/8" piece laid flat

Out of curiousity, how much relief for a tenor uke neck? I have been shown to just take a few careful passes with a sanding block on the fretboard before fretting, a difficult to measure amount.

Thank you for the info!

4.6mm is pretty far off 1/4", but still, yeah, I guess too thick

Chris_H said:

I use CF in my uke necks, a 1/2" x 1/8" piece laid flat

Out of curiousity, how much relief for a tenor uke neck? I have been shown to just take a few careful passes with a sanding block on the fretboard before fretting, a difficult to measure amount.

Thank you for the info!

4.6mm is pretty far off 1/4", but still, yeah, I guess too thick

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I don't think 1/2" X 1/8", especially when laid flat, is the best choice.
I set my neck relief at about 5 or 6 thousandths. A dollar bill, folded in half, will give you a place to start. I use one of those Al Carruth scrapers for a cleaner, flatter cut than sandpaper can give you.
Sound and playability are the single most important factors to me when I build. I take my time during fretting and set up and don't take short cuts. Regardless of how it looks or how much it costs or how much it weighs or how long it will last, an uke is worthless in my opinion if it's not a joy to play.

Moore Bettah Ukuleles said:

I don't think 1/2" X 1/8", especially when laid flat, is the best choice.
I set my neck relief at about 5 or 6 thousandths. A dollar bill, folded in half, will give you a place to start. I use one of those Al Carruth scrapers for a cleaner, flatter cut than sandpaper can give you.
Sound and playability are the single most important factors to me when I build. I take my time during fretting and set up and don't take short cuts. Regardless of how it looks or how much it costs or how much it weighs or how long it will last, an uke is worthless in my opinion if it's not a joy to play.

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I love playing my Beautiful Moore Bettah...Thanks Chuck!

the fretwork is the best I have seen...you can tell Chuck puts a lot of time and effort into it....
now when I get a nice ukulele in my hands,I look down the neck to see if there is any neck relief built into it...

not to many builders do it...but seems to be an important part of the ukulele build...IMO

my 2 cents

Keep in mind that most ukes built with no truss rod or reinforcement rod will develop some relief naturally after a while due to the string tension. The down side to that is that you can't control it.

Chris, I'm using the same saw blade but I tap my frets in. I think I have more control that way and can actually set them more even. I'm using the same StewMac #764 wire but I thin my fretboards to 0.157 and have not had any problems. I use the CF rod too but 3/8x1/8 edge wise instead of flat. I haven't been putting relief in the FB but I will give it a go on my next. I have a baritone order so with the longer neck it might be necessary.

resoman said:

I haven't been putting relief in the FB but I will give it a go on my next.

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Approach neck relief conservatively. It's not a case where more is better. Too much relief will cause the strings to buzz higher up on the finger board. A matter of a couple of thou either way can make a difference.

hmmmm.. I started out putting in 3/8" x 1/8" vertically, but switched up to the larger size based on some words that Rick wrote.. another case of different ways.. I am not sold on it by any means, though I am sure it still adds a lot of stiffness. I guess maybe I should do some flex testing, maybe break a neck or two... simple enough to measure deflection of an unbraced neck, and the 2 different orientations, deflection under a given weight, and the type of failure, and when. Of course this still would not pass 'scientific' muster....

I am not a trained structural engineer, and have not searched out the equations to find out about how different amounts/ positions of CF affect neck stiffness.

Anyone?

resoman said:

Chris, I'm using the same saw blade but I tap my frets in. I think I have more control that way and can actually set them more even. I'm using the same StewMac #764 wire but I thin my fretboards to 0.157 and have not had any problems. I use the CF rod too but 3/8x1/8 edge wise instead of flat. I haven't been putting relief in the FB but I will give it a go on my next. I have a baritone order so with the longer neck it might be necessary.

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I am curious about why an arbor press would set frets unevenly. I pounded them in at Pete's place, so I have felt what it feels like to set them with a hammer. With the press, they go in smoothly, never an issue. At full depth, I use the arbor kind of as a hammer, if you can imagine that, to set them fully .

My radiused fretboards are 0.150" at the side. I did not want to go thinner, as then the binding looks too miniature.. maybe a reason to rethink the radius? I like the radius though... The crown of the board in front of me is 0.183" so about 25 thou thicker than yours. Good to know I can go thinner. Thank you.

Chris_H said:

I am curious about why an arbor press would set frets unevenly. I pounded them in at Pete's place, so I have felt what it feels like to set them with a hammer. With the press, they go in smoothly, never an issue. At full depth, I use the arbor kind of as a hammer, if you can imagine that, to set them fully .

My radiused fretboards are 0.150" at the side. I did not want to go thinner, as then the binding looks to miniature.. maybe a reason to rethink the radius? I like the radius though... The crown of the board in front of me is 0.183" so about 25 thou thicker than yours. Good to know I can go thinner. Thank you.

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Look at some of the earlier ukes. Those fret boards were less than 1/8" thick. I've also heard that a thick fret board can dampen the sound, especially if it's ebony. Besides, thick fret boards just look bulky.

Chris_H said:

hmmmm.. I started out putting in 3/8" x 1/8" vertically, but switched up to the larger size based on some words that Rick wrote.. another case of different ways.. I am not sold on it by any means, though I am sure it still adds a lot of stiffness. I guess maybe I should do some flex testing, maybe break a neck or two... simple enough to measure deflection of an unbraced neck, and the 2 different orientations, deflection under a given weight, and the type of failure, and when. Of course this still would not pass 'scientific' muster....

I am not a trained structural engineer, and have not searched out the equations to find out about how different amounts/ positions of CF affect neck stiffness.

Anyone?

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Whether it's sound board bracing or floor joists, any beam will be much, much stronger if laid on edge. I use 1/4" X 3/8" rod, laid on edge. For you mathematical types (which I'm not), the strength of a beam goes up with the square of the depth of the member. So if I'm not mistaken a 1/8' X 1/2" beam will be 8 times stiffer on it's edge than if laid flat. One of you high-dome people here will correct me if I'm wrong.

Chris_H said:

Words that I found on the net that most concerned me are that perhaps the StewMac saw blade is designed a little thin for their wire? Doesn't seem like that could be, as it would be too easy to fix.

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That was the case with my uke as the barbs were larger than the saw used. Sent it back and he had to refret the uke and add neck relief. Lesson learned and he will now put in neck relief for all his ukes.

I recall seeing a recommended Stewmac saw but it's not listed anymore...I guess someone complained that it didn't fit correctly. HAHAHA

Of course your saw could be larger.

nongdam said:

That was the case with my uke as the barbs were larger than the saw used. Sent it back and he had to refret the uke and add neck relief. Lesson learned and he will now put in neck relief for all his ukes.

I recall seeing a recommended Stewmac saw but it's not listed anymore...I guess someone complained that it didn't fit correctly. HAHAHA

Of course your saw could be larger.

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You are getting bad information Daniel. The barbs of the fret tang need to be wider than the fret slots otherwise they wouldn't hold. That's what the barbs are there for. The StewMac slotting blades when used with the StewMac fret wire work for thousands of luthiers.