Frets causing back bow

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TallDad71
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Frets causing back bow

Post by TallDad71 » Wed Dec 07, 2022 5:39 am

My fret saw is 0.5mm, my fret tangs are 0.5mm wide so why when I install the Frets do I get a back bow on my fretboard I wonder?

I secure them in out of habit with titebond, I can see how that might not be necessary but can’t see why that would add to the back bow.

Any thoughts and tips would be really appreciated please.
Alan

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Allen
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Re: Frets causing back bow

Post by Allen » Wed Dec 07, 2022 6:23 am

I use the standard width tang fret wire and had used the SM 0.023" fret saw until I changed to doing slots on my CNC. When my fret slots were cut straight through on the table saw my fret boards always had a back bow.

When I switched to blind fret slots (similar to a bound fret board) my fret boards lay dead flat. Conclusion is that blind fret slots or bound fret boards are far superior.
Allen R. McFarlen
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kiwigeo
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Re: Frets causing back bow

Post by kiwigeo » Wed Dec 07, 2022 9:30 am

Possible reasons:

1) There'll be a bit of water from the Titebond glue swelling the wood around the slot.
2) Saw might not be exactly a 0.5mm kerf...especially if its had a bit of use.
Martin

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Steve.Toscano
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Re: Frets causing back bow

Post by Steve.Toscano » Wed Dec 07, 2022 10:13 am

Double check the kerf and the fret tangs. I suggest they aren't right.
OR
Try softening the top corners of the slot with a small triangular file.

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Trevor Gore
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Re: Frets causing back bow

Post by Trevor Gore » Wed Dec 07, 2022 8:25 pm

TallDad71 wrote:
Wed Dec 07, 2022 5:39 am
My fret saw is 0.5mm, my fret tangs are 0.5mm wide so why when I install the Frets do I get a back bow on my fretboard I wonder?
I'm guessing that the 0.5mm measurement doesn't include the barbs (or the frets would just fall out). The barbs will force a bit of back bow, especially if you're fretting into really hard wood. If you're using Titebond as well, when you have finished fretting just invert the fret board over a 6mm high strip of cork in the middle of the fret board and clamp the ends down over night (so putting some temporary forward bow into the board). When you release the clamps in the morning the fret board will be close to straight and you will know that the barbs are properly embedded in wood and solid Titebond.

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lamanoditrento
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Re: Frets causing back bow

Post by lamanoditrento » Thu Dec 08, 2022 9:38 am

Trevor Gore wrote:
Wed Dec 07, 2022 8:25 pm
TallDad71 wrote:
Wed Dec 07, 2022 5:39 am
My fret saw is 0.5mm, my fret tangs are 0.5mm wide so why when I install the Frets do I get a back bow on my fretboard I wonder?
I'm guessing that the 0.5mm measurement doesn't include the barbs (or the frets would just fall out). The barbs will force a bit of back bow, especially if you're fretting into really hard wood. If you're using Titebond as well, when you have finished fretting just invert the fret board over a 6mm high strip of cork in the middle of the fret board and clamp the ends down over night (so putting some temporary forward bow into the board). When you release the clamps in the morning the fret board will be close to straight and you will know that the barbs are properly embedded in wood and solid Titebond.
The barbs were my first thought too.

Kinda obliquely related (but not really), TJ Thompson was recently on a Fretboard Journal podcast speaking about bar frets and using backbow to correct neck bowing/movement. He described using different width tangs at different frets, e.g. 45 thou tangs in frets 4-7, 47 thou for frets 8-11, 52 thou 12 to 16 and 40 thou 17 and above.

Some of the episode is a bit self-congratulatory and 'old guy' ramble but I thought the bar-fret stuff very interesting:
https://www.fretboardjournal.com/podcas ... rd-summit/
Trent

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kiwigeo
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Re: Frets causing back bow

Post by kiwigeo » Thu Dec 08, 2022 5:58 pm

In the clip TJ Thompson advises not to order anything from Australia..try to get it locally (ie from the US).

Is he talking about these"?: https://www.thesandpaperman.com.au/sia- ... -fine.html

Couldn't find any reference to bar frets in the video clip...
Martin

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lamanoditrento
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Re: Frets causing back bow

Post by lamanoditrento » Fri Dec 09, 2022 4:20 pm

kiwigeo wrote:
Thu Dec 08, 2022 5:58 pm
In the clip TJ Thompson advises not to order anything from Australia..try to get it locally (ie from the US).

Is he talking about these"?: https://www.thesandpaperman.com.au/sia- ... -fine.html

Couldn't find any reference to bar frets in the video clip...
I think these https://hobbyshopmelbourne.com.au/produ ... s-full-set
Trent

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Re: Frets causing back bow

Post by simso » Fri Dec 09, 2022 9:20 pm

Measure the wire and the tangs, very rarely do i find them to spec, especially if they are from stewmac, good products but pretty off spec most of the time the stuff I have gotten from them

Do you have barb files, that allows you to trim the width of the barbs, my test for frets is it should fit into the slot with thumb pressure to the barb and then gets hammered or pressed home to set the barb.

Ebony boards are very unforgiving for a tight fitted fret, very easy to get backbow

Steve
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Do your own repairs - http://www.mirwa.com.au/How_to_Series.html

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