Frets causing back bow
Frets causing back bow
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.
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
Peregrine Guitars
Peregrine Guitars
Re: Frets causing back bow
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.
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.
Re: Frets causing back bow
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.
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
- Steve.Toscano
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Re: Frets causing back bow
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.
OR
Try softening the top corners of the slot with a small triangular file.
- Trevor Gore
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Re: Frets causing back bow
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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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.
- lamanoditrento
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Re: Frets causing back bow
The barbs were my first thought too.Trevor Gore wrote: ↑Wed Dec 07, 2022 8:25 pmI'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.
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
Re: Frets causing back bow
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...
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
- lamanoditrento
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Re: Frets causing back bow
I think these https://hobbyshopmelbourne.com.au/produ ... s-full-setkiwigeo wrote: ↑Thu Dec 08, 2022 5:58 pmIn 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...
Trent
Re: Frets causing back bow
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
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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