Fretting a Compound Radius Fretboard

eldegenerate

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Hi, I am building my first ever guitar and am getting pretty close to being done with it. However, I am a bit confused when it comes to fretting. I bought a pre-radiused fretboard from stewmac and when I purchased it I was unaware of what a compound fretboard was. I now know what it is however I am unsure about how to go about installing the fretwire. I was originally planning on buying pre-radiused wire, but I dont know if that is a viable option anymore. The compound radius starts at 10" and at the 22nd fret is 14", does anyone know if I could still use pre-bent wire or have any tips for me?
 

guitarbuilder

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If it were me...I'd save the fretboard for another build and get another one with a single radius. Fretting can be hard enough on your first build and I think a compound radius will make it even more of a hassle. I'd also suggest you get straight fret wire and make a simple bender so you can overbend the wire a bit for your particular radius. Stewmac has fretwire in 2 feet lengths. I'm a convert to a fret press, so if you have access to a drill press, I'd get a caul to match your radius and press the wire in. This may help.





 
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Ronkirn

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remember when fretting a board, the fret being installed should be bent to a radius smaller than that of the fingerboard. I. E. a 7.25 would be perfect for a 9.5 board.

Since a compound radius board is a gradient use a smaller radiused fret-wire, checking until the board flattens somewhat, then move up to a different "bend" on the wire... depending on which way you move... I wouldn't just bend it to a generalized radius and use it on all the frets...
 

JohnnyThul

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Actually,the first guitar I ever built had a compound radius.
What I did was what @guitarbuilder suggested, first get a fret bender and bend the frets to a smaller radius than the smallest fretboard radius.
And then I hammered the frets in with a soft blow hammer (take your time, not too much force for the first blows and aim correctly). That worked out surprisingly good and easy.

Later on, I switched to 12" radius for all guitars I made since then and I invested in radiused pressing cauls which works much smoother and consistent, than the hammer.
Funny enough, the difference between compound 10-16" Vs the 12" radius for me was very negligible once I could compare.
 

gb Custom Shop

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I agree with @guitarbuilder. Single radius boards and pressing in frets is easier to achieve excellent results, especially for a first build.

There are a lot more considerations when using a compound radius board. And if it's 10-14", then ideally your bridge/saddles should have a radius of ~16". I.e. the compound radius extends to the bridge, not just the end of the fretboard. Lots of people overlook that.

However, if you were always going to hammer in frets, and your bridge is suitable for the radius, and you don't want to buy another fretboard... then you're better off bending your own fretwire as opposed to pre-bent. You need about 3 pieces of straight wire in total, so you can bend each piece to a different radius for different sections of the fretboard.

FWIW I wouldn't expect hammering frets to go perfectly on your first go. It takes a bit of practice but thankfully the more you do it, the more of a feel you'll get for it. I would also suggest getting fret pullers in case you need to reseat frets.
 

old wrench

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Almost all the necks I've built use a compound radius

My favorite compound radius is sort of vintage, approximately 8" to 11" - with approximately 12" bridge saddle radius

For those necks I get by using wire pre-bent to two approximate radii - 7-1/4" and 10" - but, depending on how hard the fret-board wood is, I'll make slight radius adjustments as I go

I generally use medium-jumbo stainless-steel wire*

I don't say "approximately" to be purposely ambiguous - small differences in fret-board radius are actually - very small ;)

One or two inches of difference in fret-board radius sounds like a huge amount, but when you get right down to actually measuring the difference over the width of the fret-board - it's a very small amount, not nearly as much as it sounds


Yes! :) - you do want your wire bent to a tighter radius than the board - as you press or hammer the fret in, the force tends to flatten-out the fret, so using an over-bent radius fret helps to compensate for that flattening action and helps to keep the fret ends seated.

But! :) - the amount of pre-bend depends on a few different factors


- One factor is the method used seat the frets - hammered or pressed?

If they are pressed in, I find less over-bend is needed - exaggerated hammering can actually put a reverse bend into the fret where the frets ends want to rise up and come out of the slot - the more you hammer, the worse it gets!

- Another factor is fret material - nickel-silver, or stainless-steel, or copper-nickel (Evo), etc, - and how resistant the material is to bending

I find stainless-steel is the stiffest, followed by copper-nickel, and nickel-silver bends the easiest - so I use less pre-bend with stainless - stainless is stiffer, but it's also pretty "springy"

- Another factor is fret size - obviously, jumbo size fret-wire resists bending more than skinny vintage wire


So, I don't use much over-bend when I'm pressing in medium-jumbo stainless-steel frets because they are stiff and springy

On the other hand, if I was hammering in skinny vintage size nickel-silver frets, I'd use more pre-bend


I think having fret slots cut to a consistent width that is sized for your wire (right depth too) and properly prepared (clean-cut and lightly beveled), is a great help to get the fret to set down in the slot


So, after all that yapping, blabbing, and typing, I'll just say that the easier the frets go in, the less over-bend you need, but you do need to start out with some over-bend

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