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There seems to be a lot more options out there for (short scale) acoustic bass designs. Cordoba, taylor. U bass...
Can I purchase a design somewhere I can adapt to a OOO body?

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Mike McNerney

Sorry for the "senior moment" I asked the same question 1.5 years ago. I got some advice but no plans yet

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Mike McNerney

I think that if you could do the tension calculations and find out how different they are from a guitar you could probably just adjust from there. As far as the bracing goes.

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Pat

I recently built an acoustic bass with a J200 body but it had a 34" scale. I modified the bracing that was used in a plan by Mark Stanley I got on eBay years ago. Waldron guitars has templates and parts for that bass. It's huge though. There are several other plans on https://www.liutaiomottola.com/. What scale length are you thinking of building? If anything like 20" to 25" scale, I'd just use a 000 plan and draw it up with a neck the length you want and join it to the body at whichever fret gets the bridge to match up with the 000's plan location. Depending on the string gauge you're planning to use you might want to increase the height of the X brace by 1/8" or so.

I am thinking something like the taylor Mini Bass 23.5" scale Taylor designed a nylon string for it & I like the sound. So you are suggesting just making the x brace 1/8" higher and what about the soundboard thickness. I can do the rest. thanks

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Mike McNerney

If stringing with nylon you probably don't need to modify anything per bracing/ top thickness from the 000 specs, or find out what the bracing looks like on a Taylor and use that and check Taylor's top thickness. Are you going to add a pickup? I suggest JJB. Check the advice I got on this post viewtopic.php?f=10101&t=52222.

I realize that this thread is a couple months old and probably shouldn't be in the electric guitar forum at all, but I happen to have an acoustic bass on my bench for a couple of days and thought that maybe I could help Mike with his design. I PM'ed him and told him that I would just take a whole bunch of measurement off it and post them to his thread - that way others could comment. I do however think there is a lot to be said for moving this to the general acoustic subforum.

Anyway, guitar is s Spector Timbre TB-4 acoustic/electric bass.



It is spruce over what looks to be sapele, has a Fishman UST but the owner plays it both plugged and unplugged. I'll just list all the measurements I took off of it, then discuss a couple of interesting things. All measurements are in inched unless otherwise noted

Scale 34", 22 frets, body joint at 15
Body length 21"
Lower bout 17-1/4
Upper bout 12-1/2
Waist 10-1/4
Depth at neck 4"
Depth at tail 5"

Top thickness - 0.125
Top dome ~ 1/8 measured behind the bridge
Sound hole 2-5/8 x 5

The neck is a bolt on some what like a Fender but with inserts. Neck block is 4-1/4 long by 3-1/4 wide and extends from the top to the back
The neck heel is 1 inch thick at the outside edge (I did not measure the f/b radius)
Neck angle 2 degrees. The neck has about 1/16 of overstand and parallels the top upper bout
Bridge 1/2 tall
Saddle is 0.160 to 0.180 above the bridge
Strings 0.046 to 0.100
Tuning EADG one octave below bottom 4 strings on an acoustic guitar.

Back bracing is 5 ladders at 3/8 wide and 3/4 tall (approximately, a little difficult to measure
Top bracing is two spruce braces 3/8 x 3/4 running from the neck block to the lower bout kerfing. Probably tucked, I can't tell. The braces run under the wings of the bridge.
There is one ladder cross brace at about the front edge of the bridge that is notched into the top braces.
All braces are tapered to a point on top. The ends are scalloped but there is no scalloping on the brace themselves.
Bridge plate between the top braces

I have sketched the approximate location of the top braces on this



Hope this helps, Mike, if there is anything else you would like me to check I will have this for a few days