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Converting an Acoustic Guitar to a Bass, and String Selection

#102
Since discovering the fretboard radius of most basses is much smaller than a 6 string guitar I'm rethinking my design. Last night I read many posts here about how some people prefer a small radius, and some a large radius. It's a personal thing. I can see how a small radius would make it easier to not trip over strings. Converting a 6 string guitar presents another problem that the fretboard is only ¼" (.25") thick with approx .01" deep slots for the fret tangs. When you add a curvature to that, it makes the slots close to the bottom of the fretboard. This might not seem like a problem, but when doing a neck reset the fretboard extension is hanging out in air, just waiting to be snapped off. I've done that once! Since I have the 12" radius sanding block I don't think there would be a problem changing from a 16" radius. IS THERE ANY LOGICAL REASON WHY I SHOULD PUSH FOR 9.5" RADIUS??? The fret slots would probably be .02" deeper at the edge of the fretboard.

BUT!!! Throwing the radius into the equation, the flat single adjustable saddle won't work. I'm trying to make it as low as possible. I'd have to make some deep notches in the saddle to get the action correct for the E & G strings. I'm going to have to redesign the bridge & saddles to take the probable 12" radius into account. That sends me back to just the individual saddles.

So I did a radius layout. I've spread the saddle string spacing from 2" to 2-1/8". That's the max I can go with the width of the fretboard. For reference, the nut is 1.70" wide with a 1.30" string spacing, leaving .20" between the center of the outer strings and the edge of the fretboard. With a 2" saddle string spacing the outer strings are .17" from the edge of the fretboard at the 21st fret. When I open that up to 2.125", the strings are .13" from the edge at the 21st fret. BUT, .15" at the 12th fret. I'll be sure to make the fret ends as flat as possible.

Also, a few people have mentioned they don't like Jumbo frets. That seems to be the standard with basses and electric guitars, probably to make the frets last longer. They are also a little higher, making it easier to press too hard and alter the pitch of the note. I've already bought the Jumbo fret wire. That's what I was planning on putting in. But all my vintage Yamaha's have narrower & slightly lower frets. Obviously bass strings are much thicker and harder to bend than acoustic guitar strings. But the nylon core strings I'll be using will certainly bend easier than steel acoustic guitar strings. Now I'm wondering if I should stick with the smaller fret wire!!!

ALSO!!! I'm considering converting this guitar neck to BOLT ON, due to the possibility of later using steel strings and the additional tension causing the neck to pull up (not to be confused with neck relief) and require another neck reset to bring the action down. I'll keep the dovetail joint, just not glue it. I bought the inserts a couple of years ago but never used them. Maybe consider adding some additional reinforcement in the neck block area to keep it from forcing the top any lower near the sound hole, or maybe even reverse it slightly.

Yea, more changes. But I'd rather make changes in the planning stage vs. after the guitar is built.

AND!!! If I scrap the single saddle option, the individual saddles with be much lower and I DON'T need to do the full mockup!!! SBASSMAN!!! You got your wish!!!

BUT!!! I do need opinions on what fretboard radius and frets I should use. I'm going to start another version based on individual saddles and a 12" fretboard radius.
Fretboard Radius Layout.jpg
 
#103
Use the radius you like. I usually prefer a flatter radius and there are guys here who build or have have built basses with flat fretboards and like them. I think the the smaller radius comes from "tradition" (Leo did it that way) and, perhaps, upright bass as much as anything.

Same with frets. If the instrument is for you, use what you like. As long as they're level and in the right places, I'm not too picky about fret sizes.

For the fretboard extension, will it be off of the body enough to make a piece to glue under it similar to what would be on an archtop guitar?
 
#104
Matt Liebenau said:
Use the radius you like. I usually prefer a flatter radius and there are guys here who build or have have built basses with flat fretboards and like them. I think the the smaller radius comes from "tradition" (Leo did it that way) and, perhaps, upright bass as much as anything.

Same with frets. If the instrument is for you, use what you like. As long as they're level and in the right places, I'm not too picky about fret sizes.

For the fretboard extension, will it be off of the body enough to make a piece to glue under it similar to what would be on an archtop guitar?
Click to expand...
Well, there's the problem. I don't know what I like!! I'm not a bass player. Yet.

If I raise the fretboard I'll have to raise the saddles, or raise the bridge, which I can't do if I'm using the Taylor pins. I'm going to lower the saddles as much as possible. But the neck angle sets the action. Another reason to convert the neck to bolt on.

I'll probably keep the Jumbo fret wire and put my standard medium wire in.
 
#106
Matt Liebenau said:
In that case, just go with what's already on the neck. Keep it simple.
Click to expand...
I had already pulled most of the frets (with the intention of putting in Jumbo's), so I'll remove the rest and sand the fretboard from 16" to 12" radius. And deepen the slots. I had to open them anyway, the old Yamaha frets have thinner tangs than modern frets.

It's amazing how this continues to evolve!
 
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#107
alder said:
A small radius makes it easier to form chords on a guitar, but can cause notes to 'fret-out' when bending strings. On a bass, radius makes no real difference. I use 12" on everything. Anything between 10 and 16 is fine. You'd have to be really picky to even notice.
Click to expand...
That's what I've read. I can see the difference in a layout, but who knows if I'll notice in reality.

I doing a neck reset and frets on a vintage Yamaha FG-140. I'm going to sand the fretboard to 12" and see if it feels any different.
 
#108
While I agree it is more common for bigger fretwire on a bass, I have always wondered about that.

I often design my ultimate bass - in my head :) - and I'm always thinking when I hit Lotto and pay someone a big pile to make a great bass My Way, that part of my way will be - very small fretwire. I'm thinking small fretwire wire will be the ultimate balance between fretted and fretless. Enough to help with the intonation, but small enough to maybe easily catch some fretless vibe.
 
#109
I saw the Savarez Lower Octave 65cm scale classical acoustic strings discussed here and last week I put some on a 70s Alvarez 12 string (steel string), and I'm pleasantly surprised how nice they sound. They aren't loud but I did not expect them to be. The 12-string actually had an old Dean Markley pickup mounted with volume and tone knobs mounted on the side - but the lower octave strings made the pickup loudly vibrate/buzz so bad that I unmounted the pickup while I was away from any amps to see how it sounded. I'll eventually try to fix the buzzing and try the pickup out, but this guitar is intended for noodling on trips and not amplification so it will only stay on if it doesn't lower the acoustic volume. Here is a link - I didn't find any other options in the US for a 25" scale but I didn't look super hard: Invalid Link Removed
 

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