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So I have been making an acoustic bass guitar and I don't know how I have got this far but I have discovered I have made a boo-boo! The offset from the centre line to the edge of the cutaway should be 27mm but I have somehow managed to make it 33mm! So with the neck width at the body joint 54mm on the plans I have a couple of option, neither of which sound great. I can keep to the 54mm width on the centre line and have a 6mm ledge to the side of it, I can keep the 54mm width and move it down so it lines up with the edge but the strings will be offset from the centre of the box. I am guessing just making the neck 12mm wider is a non starter? I have never played a bass so not sure how unplayable this would make it?

Any advice is greatly appreciated!

Just a wild idea, but what about a 5 string bass? I suppose the headstock is already sized for 4 strings with your 12th fret width.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I would leave the 6 mm ledge, and center the fret board with the the center seam and the sound hole. Write it up in the specs as a palm rest, and up charge at least $200.:>)

If you can figure a way to make the binding look right in that area, you could bevel the ledge, to transition with the edge of the fret board.

Lee: How about keeping the 54mm width, mount the neck as you intended, slope the neck so that the bridge ends up on center and cut the saddle slot to allow for the slop of the neck. Draw it out full size to see how it looks. Short of major reconstruction, don't see too many alternatives.
Tom

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A person who has never made a mistake has never made anything!!!

I'd probably leave the nut width and bridge spacing the same, and increase the fingerboard width at the body join. But not by the full 12mm. Even though leaving a ledge there is a personal peeve of mine, it's common enough that most people probably won't be bothered by a small one. You could probably get away with offsetting the neck 2mm or so toward the treble side without drawing attention, to further reduce the ledge.

Too bad your binding is already done... wide purfling, especially with shell, can make it look like you left the ledge visible on purpose to show it off rather than have it go underneath the fingerboard.

I see two options.
1) leave a ledge. Lots of guitars have a ledge, including every Taylor cutaway. I don't personally like them but it's an option.
2) this might seem controversial but would likely be the way I'd go with it. Mound the neck crooked. Meaning, mount it so that the treble side is flush with the cutaway but the centerline of the neck will meet the centerline of the bridge. It will require the mating surface/tenon to be crooked. The bridge can remain straight but the saddle slot will be at a different angle than it would have been before. In my opinion, it's a good fix. Your fingerboard extension will cover the centerline above the soundhole so it will be completely invisible. I'd play with it and see how crooked it will have to be to get it all right. In reality, it won't be too much, I don't think.

Certainly not a fatal error in my view. Given the apparent good work you've done at the corner where the bindings join, I'd leave the ledge. I know it's just a matter of taste, but I think the ledge will create a better look than what you'd planned.. I've played all kinds of guitars for 50 years (including bass) and I cannot see that there would be any sort of playability problem.

I like Colin's idea of a five string bass. Acoustic basses are somewhat of a mutt to start with and adding a high string (EADG added C) to push it a bit more into the baritone range might be a welcome addition

I vote for a ledge!
I wouldn't even notice if you didn't bring it up.
A

Live and learn. FWIW, Larrivee cutaways are always like that.

I'd leave the ledge if it were me, 5 mm is a bit bigger than I would like but not terrible. The purfling is nicely mitered there, the ledge is not uncommon and let's face it, it is an ABG, it won't get a whole lot of playing that far up to cause any real problems.

I'm not so sure tilting the neck would be a good option here. Usually I would say go for it since you can get away with a fair amount of asymmetry but I feel that it will take a fairly big angle to get it to match up and that angle will be exaggerated with the long neck span. I could be wrong though, draw it out full scale and see what you think. You could also do a combination of the two methods and get the ledge to be smaller (match what you think will look good with the purfling) and keep the offset angle within range.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Gentlemen, I would like to thank you, one and all, for taking the time to offer advice and opinions. To be honest I hadn't even considered Colin's suggestion of a five string, and as I haven't started the neck yet this is a real possibility. The safest of the alternatives seems to be to leave the ledge although to my eye it would be less aesthetically pleasing.
Does anyone have any typical neck widths for a five string? I have had a look around the 'net and they all seem to list the width at the nut they only seem to quote the neck depth at the 12th. I was planning to make this with a 34" scale and joined at the 13th fret.
Once again, many thanks for your thoughts. You are all a splendid bunch of chaps!

https://ritter-instruments.com/stringspacing.php
This site gives his nut and bridge string spacing for his standard and vintage models.
12th fret 55 mm for standard, 51mm for vintage, if my arithmetic is OK.
66 mm would give you 5.5 mm each side clear of neck edge for standard, 7.5 mm for vintage (if you were using 12th frets to body), does that sound ballpark?
(I own up - I did check before suggesting...)

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Finally got to finish this one, and just to show how it turned out moving from a 4 string to a 5 string here are some photos!

Oh man, Lee!
It looks fantastic!
I bet it sounds like a dream!
That extra string might just come in handy.
I would never guess there was a boo-boo on it.
Dan

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wah
Wah-wah-wah-wah
Wah

Nice recovery!

Turned out really well, nice one.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Classic example of turning a mistake into a feature. Really nice job.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Nicely done?
How does it sound?
I have never played an ABG...

Thanks chaps, I think converting to a 5 string was definitely the best option. I only glued the bridge on on Saturday so I haven't tuned it to pitch yet, just loosely wound the strings on for the photo as I prefer to leave it a week before cranking it up!

Well it sure does look nice. I personally have no problem with a ledge and in fact think it looks nice to see the binding come all around. I would not have changed my plans for that guitar. That's a big change for something that is an acceptable practice IMHO but regardless the bass looks great. Good job.

very nice

Ed

Looks great!

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.