Homebuilt EUB build thread

Greetings, longtime reader, finally bothered to get an account to post a build thread. I built several guitars years ago in highschool, and have always wanted to build a bass. This year I finally set my sights not only on building a new bass for me, but building an EUB. I play 5 string electric (low B) for church band, and there are a number of times I am kicking myself because I can't get that nice acoustic sound for songs from Rend Collective or a bowed sound for some hymns.

After thinking it through, and doing a lot of hunting, I decided that I wanted to build a 5 string EUB with the same scale length as a long scale bass (34") so that my fingerings will all transfer. I also want to stick with the 5 string for the same reason, also we play enough stuff in Eb and that low D is so handy so it makes sense to me.

I would appreciate any feedback or encouragement you have to offer through the process. As an electric player there are likely some mechanics of playing an upright that I am frankly ignorant of so if there are glaring problems that you see with the design please speak out!

It will take a few months to build, and I will try to take pictures of the process as I go and post regularly.

 

How did I start down this road? I did some quick sketches to get my ideas out of my head, and onto paper. Here are a couple of paper sketches that I did early on in the design process to figure out what I wanted to build.



Early inspiration was a semi hollow body electric. I wanted something that was relatively easy to build (limited curves) but still emulated the classic shape of a double bass.

 

Coming together. taking the paper sketches, and using autocad I did some more detailed draft work to pull together some of the fiddly bits and line some things up. This is pretty close to a final design as I will probably do.

Some early design decisions that I had to make:
1 Bridges. I decided to use single string bridges, this would allow me to control the string spacing to better accommodate the strings. I have some concerns that I may limit my string choices in the future, but I also plan on drilling through the support under the bridge so that longer strings can be accommodated through the body of the bass but that limits me to an upper string diameter of ~.130" (the hole through the bridge) and about 7.5" of wrapped string end. I may wind up regretting this decision, but it seemed like a good way to start. It didn't hurt that I found them on Amazon for <$20.

2 Tuners. I plan on using electric bass tuners on this using a 2/3 arrangement for the headstock as it gave me the straightest string travel. I left room to upgrade to 'elephant ears' if I need to, but I really like the Gotoh tuners on my Spector NS-2005, and these will be identical. This will likely be one of the most expensive parts of the bass ($70).

3. Pickups. I plan on using individual pizeo pickups under each bridge, and I am of a mind to get an acoustic piezo preamp (they are cheap on ebay) that also has a microphone to use inside the main chamber, blending with the piezos for hopefully a warmer sound. I have no idea how far the rabbit hole I might go on this, but I am also evaluating building some breadboards with individual string volume / tone controls / mixing. but those are decisions I don't have to make right now. it's enough to know I need to fit a piezo under each saddle, and have a wire come out somewhere accessible.

4 Woods. in the interest of cost, I am building this out of easily accessible maple and mahogany board stock from my local hardware store. No fancy grained woods, no quartersawn pieces, just trying to keep it within a modest budget. The neck will be straight through the length of the bass, but have some cutouts to allow for better resonance in the body cavity. The front, back and sides will be mahogany. My current plan is to bookmatch a 1x8x8 (.75"x7.5"x8') to .25" and use that as the panels to build the sides using maple stringers to provide structure and a framework.

 

Some details of the headstock.

Front View:


Side View:

 

Neck through plan design: This shows the cutout plan for the neck through the body.

 

@DoubleMIDI so you would recommend going 38 - 40" or so? I was thinking (initially) to use the NS 5 string set.

 

A thought. 34" is pretty close to the 4th - 5th fret of 4/4 scale length. In theory, using an E - C set Tuned B - G, the string tension should be similar?

 

Here's how it would look if I stretched the neck to 41.5" scale length.

 

I can do this, the woodworking for it will be a little fiddly, but I have some ideas. basically, I will have to carve some flats on the slope for the tuners to sit, I am thinking that they will wind up slightly recessed from the front view. The trickiest part will be on the inside of the 'well' between the tuner sets. I'll probably have to fit the tuners before I add the bottom piece to the headstock so I can reach where the tuners are.

 

I think this falls under information that I didn't know that I didn't know. I figured BG strings = thick guitar strings = thin DB strings. instead, BG strings are more delicate and finicky. The fact that my sister has had the same strings on her double bass for decades somewhat mollifies my shock at their price tag ( ) and I thought decent BG strings were expensive!

Honestly, I rarely play above the 7th fret on the B or E strings, as the notes get 'flabby' and I much prefer a nice tight bass sound from my BG.

I will re-visit the body dimensions with the new scale length in mind, as I now think it is too small and short for the neck.

 

@Amano more like this?

 

Updated body shape/size.

 

My sisters is in Virginia, so that's a little complicated.

My original plan was to buy a replacement 3/4 fingerboard from overseas. That's become complicated for 2 reasons, a) the relief carving on the back, while necessary for a fingerboard hanging over the body of an acoustic bass complicates the joinery to attach it in a manner to avoid odd sounds from the hole in the middle of the fretboard. and b) I am not sure that with the extra size that it would work anyways, in the original plan, I was going to leave the free end alone, and cut the nut end to get the additional width for the 5th string.

Carving a multi-radius fretboard doesn't worry me too much, there are a number of simple jigs out there to help manage it (I like the one from the aussie that built a fingerboard out of poly cutting board material) I think the standard taper is from 7-8 inches at the nut to 18-24 inches at the bridge end. The part that worries me a bit is the scalloping in the middle to accommodate the string vibrations, but AFAIK that is very much a trial and error fiddly bit even for professional luthiers (which I am not). I found this article to be particularly enlightening. Fingerboard Geometry | Looking at the radius - Joey Naeger Basses

Ebony is going to be right out of my budget for this project (a 3/4"x5"x36" piece of ebony can cost well north of $100) So I am looking for something available off the shelf from Woodcraft or another hardwood supplier, maybe a piece of Paduak, Purpleheart, or Wenge as they tend to be MUCH cheaper ($30-$50).

This is exactly why I chose the bridge that I did, because I knew that I was going to have to radius the bridges to match the fingerboard. Each pair of bridges out from center will be at a different height (heck, I may find that every bridge is at a different height!) to accomodate string height, and neck angle.