The "Bassirelli" - Jim's new bass
For many years I had wanted an acoustic bass that would play like my Fender Precision bass, yet have enough volume to stand up on its own acoustically while playing with other acoustic instruments. With great hopes, I bought my Epiphone El Capitan in 2001, and although it's a great bass with a wonderful sound when played through my Fender Frontman 25B (I've played hundreds of gigs in small venues with this set up), it still doesn't keep up unplugged with other acoustic instruments.
A nice 3/4 upright bass would solve the volume problem, but the intonation would not be the same as the Fender Precision or the Epiphone El Capitan. The scale length on full size bass guitars is 34 inches, and the scale length on the upright bass is about 41 inches - impossible to use all four fingers on incremental semitones in the lowest register of each string. Plus, the bulk of carrying one of those beasts around... I did have the opportunity to play an Ernie Ball Earthwood bass guitar during a cross country train trip in 2001. It played easily and projected well, but long since out of production, these basses are nearly impossible to find and are usually quite expensive.
I decided that the time had finally come to build my own bass since there was really nothing on the market that incorporated all of the design features I was looking for.
This is the story of the building of that bass:
||In 2006, while building our studio, I had to cut down a few trees on
the property to
enable truck access. One of those
trees was a poplar, and from that downed tree I cut a log that was about four feet long
to save for a future project. I skinned
the bark off, and set it aside in a corner of the studio for another
five and a half years, knowing that some day it would have a greater
Fast forward to January 2012...
In the design phase (which by the way, continues to evolve!), I decided that the body should resemble an instrument in the violin family, but for portability purposes would not be as large as a double bass, but maybe about the size of a cello. In order to improve the resonance of the body compared to an acoustic bass guitar, this bass would have a bridge and tailpiece like an archtop guitar. This would cause the tension of the strings to create downward pressure on the top at the site of the bridge, and the top would not be pulled up by the attachment of the strings because the tailpiece would transfer that load to a block in the base of the instrument. That would allow the top to be more resonant since the construction could be much lighter and would not require stiff bracing.
One other major design characteristic was that the scale length should be the same as my other bases (34") for playability, so that my intonation would be the same on this neck as it was on the Fender P bass and the Epiphone El Capitan. I also decided to make the neck bolt on to facilitate any changes that may be necessary due to the experimental nature of this project.
I started doing some full scale sketches, and started cutting this nice dry log to create some lumber that would soon become the neck on this hybrid bass.
|Even though I had owned and operated a well equipped cabinet shop in Honolulu
many years ago, one of my objectives was to be able to create this new bass
using some really basic construction tools.
These are the tools I am using for this project. The table saw is a cheap, 10", lightweight (very portable) jobsite saw. The chop saw is a 20 year old, 10" Makita miter saw. This guy has been around the block a few times! The circular saw is a Skil 77 that is at least as old, in fact, it's a Golden Anniversary model (what year was that? maybe 1987?). The Makita router is also of the same vintage, and in remarkably good shape. The Skil jig saw is one of the newer tools; it's a 2005 model (I finally had to replace my 1981 Black and Decker!), and the drill is a 2008 Hitachi, battery powered, with a 3/8" chuck. The rest of these tools include some files I inherited from my father (and his father?), some 30 year old Pony pipe clamps and a variety of C-clamps. Nothing fancy here.
As you can see, I'm not bragging about my great collection of hi-tech, modern tools. On the contrary, the point is, if you are inclined to create an instrument for yourself, you are not limited as much by the quality of the tools as you may be by your innovative and skillful use of them.
||First step was to rough out the neck. To
get started, a bit of freehand work on the table saw was necessary to turn
that log into some useable lumber.
Soon I had some square and parallel edges and was able to layout the shape I had planned. Some of the cuts required making some primitive jigs to make the angular cuts.
I did need to glue up an extra block on the back of the head to accommodate the full thickness of the head due to the angle of the tilt.
I waited to attach the heel to the neck until the body was completed so I could be sure that the angle of the heel in reference to the neck would match the bump in the arched top of the body and the height of the bridge.
|In Asheville, I purchased a 5' x 5' sheet
of 1/8" birch ply. I determined which way it was most flexible, and based
the grain direction of the sides, top, and back so that it would be easy to
The C-bouts were the tightest, with their 3" radius. Leaving the side strips outdoors for several cool humid nights made them a bit more flexible, and I worked them slowly into the inside of a half piece of scrap 6" PVC pipe, and left them clamped up for a few more days. Then I built a frame of internal bracing from some local pine that had been sitting around in the shop for a few years, and glued them into their permanent home.
I glued the sides of the upper bout and the lower bout to blocks made from more of that local pine. I drilled two holes in the neck block, and one in the tail block, putting threaded brass inserts into these holes that would later accept the bolts for the neck and tailpiece.
Finally, I glued the upper and lower bouts to the C-bouts, and voila! - this instrument has a shape!
||Most violin style bodies use a bass side brace
called a "bass bar" on the top
and a sound post between the top and back sitting just behind the treble
side of the bridge.
I decided to try a center brace on both the top and the back which would set the top and back contours, and connect them with a "wrench" shaped sound post which locks in to notches in the top and back braces.
I made a female dovetail cut in the neck and tail blocks with the router and made a corresponding male cut on the table saw to create the end to end braces, then cut the top and back arched contours with the jig saw.
Although the center braces on the back and top are glued in place at the neck and tail blocks, I did not glue the connector brace (in deference to the traditions established by builders of the violin family). Instead, prior to assembly, I coated the surfaces of the notched pieces with glycerin soap.
|In preparation for attaching the top and
back to the sides, the mating surface of the sides needed to be increased. Instead of using a kerfed liner, as is common on
most acoustic guitars, I cut several strips of the 1/8" birch ply, which were very easy to
bend, and glued them to the sides, lamination style, creating a wide enough surface to glue the
top and back. They're very strong.
Ordinary spring type clothespins made great clamps for this process.
|Designing the F-holes for the top took quite a bit of
thought and deliberation. I looked at the styles, sizes, and placement of
Knowing full well that in so many ways this bass was breaking so many of the rules, I still wanted to show respect for some of the traditions that had inspired its design. I also needed to work with the properties of the 1/8" birch ply. I knew that if I cut fully open F-holes the bent contour of the top would cause a height discrepancy between the sides of the F-holes; the edge closer to the center would be higher and out of plane with the edge closer to the side.
My design incorporates a modern, stylized F shape that is disconnected in the center (to prevent the edge to edge height discrepancy), and uses shaped, pointed holes in place of the traditional centerlines to mark the bridge location.
|The end to end braces which were dry fit
to hold the body shape while gluing the liner were now glued to the top and
Then I built two jigs from plywood scraps and 2x6's that approximated the outer shape of the bass. These jigs would facilitate the gluing of the top and back to the sides while allowing room for the "bump" on both top and back. They kept even pressure at the perimeter while reducing the number of clamps necessary to get the job done.
These jigs continued to be useful later during the sanding process.
|Simultaneously gluing the back and top to
the sides was a little bit of a challenge. Having the jigs and clamps all
set up and adjusted in advance was a big help. I left the whole assembly
clamped up overnight to maximize the holding power of the glue as there was
a lot of tension on the top and back to produce the arching in both pieces.
Despite this effort, I had one area that popped and needed to be re-glued.
I used the router with a flush cutting bit to trim the over-sized top and back to conform roughly to the shape of the sides, but the router doesn't sit squarely to the sides when riding on an arched top and back, so there was quite a bit of hand work with flat and round files to flush those edges.
|Creating the binding was another new challenge!
I cut 1/4" x 5/32" strips of poplar (about twice the lineal footage of what I would need), shaping the edge with a radiusing bit on the router. Even though I had cut the narrow dimension parallel to the grain, I found that it wouldn't easily bend to the contours of this bass.
After searching the web for wood bending methods, I found a great article and accompanying video in Fine Woodworking Magazine's website, that used a hot pipe. This became my bending method.
I used the table saw as a base for this part of the project because it was really quick to set up and the aluminum surface was resistant to the heat. Not shown in the photos is a C-clamp on the far side of the 1-1/2" (inside diameter) pipe, holding the pipe to the top of the table saw. That pipe was hot!
Keeping the temperature of the pipe in the correct range and indulging my own patience proved to yield the best results. It was a good thing that I had cut enough extra material to experiment with!
||Now it was time to glue on the binding.
At first, I tried to dry fit
entire pieces using a strap as a clamp, but as convenient as this could have
been, I found that it was nearly impossible to maintain even pressure all of
the way around the bouts.
The best method, using the tools at my disposal, was to glue and clamp about an inch or two at a time.
|With the binding on, the body was now ready for sanding.
Lots of hand work here, and those photos aren't very interesting!
I started with 80 grit in a few places just to knock off areas with excess glue or that were still out of alignment. I moved quickly to 120 grit, treating the whole body. Common emery boards were helpful here, too, especially to shape the edges of the binding.
I followed with full treatments of 180 grit, 220 grit, and finally 320 grit. Now this baby was really smooth!
Here's the body hanging outside the shop ready for a finish.
||I decided that a nice, non-toxic shellac finish would also
yield the best acoustic properties. Traditional methods of applying shellac,
such as French Polish, are highly respected among connoisseurs, but I wanted
to short cut this process a little without sacrificing too much in quality.
While I am a decent woodworker, I'm not a professional finisher.
I'm using Zinsser shellac, and started with a clear base coat. I shot a little more than one can of the spray version to get started, but then bought the shellac in a quart can and began using a Preval sprayer (see the next section). I shot about half a quart of the clear shellac using this method, but sanded so much off in between coats that I bet maybe only a half pint was left on the instrument. Thinner coats with sanding in between are much easier to work than thicker ones.
Now that the grain was sealed, I started sanding again with 320 grit (dry), and I'm preparing to recoat.
|320 grit wet and dry paper (wet) proved
to be the best way to go, and after several coats of clear
shellac, I started to use Zinsser amber shellac. There is no spray version
of this product on the market, but Preval makes this cheap ($4.99) sprayer that
did a fair job of applying it. I don't really care for the circular spray
pattern in the tip of the little sprayer (a fan type would make it much
easier to produce professional results). I went through about a half dozen
of the little replacement aerosol cartridges (called "Power Units") to spray
I finally got the color I was looking for on the body, and it was time to get back to work on the neck...
||I glued up some pieces of the same
poplar log I had cut the neck from to make the heel. Now that I had the
exact dimensions of the "bump" in the top, I was able to accurately
the angle of the heel where it would join the neck.
It is interesting to note that soon after I had gotten to this point in the project, I ran into my friend and colleague, John Yurko, who is not only an accomplished architect, but also a very talented fine woodworker who happens to have a passion for acoustic guitars. Showing John the "in progress" project, he was intrigued. As he looked the instrument over from top to bottom in its raw state, he pointed to this joint of the neck to the heel, said, "Jim, don't you think that may be a weak spot?"
More on that later...
Using a hole saw for the outer circular cut and my trusty Swiss Army knife to remove that material, I cut some more of the scroll top on the head until it had a pleasant shape, cleaned up the cuts in the slots for the machines and the slot for the nut.
After some experimentation on pieces of the scrap from cutting the neck, I started on the inlay for the side of the neck. On the edge of the neck, I used pieces of 1/8" diameter bamboo skewers for the dots, and pieces of wooden coffee stirs for the position markers. This is a fretless neck, and I often use the term "fret markers" to describe these edge markings to identify the place that frets would have been on a fretted neck, but I suppose "position markers" is a more appropriate term.
Using a combination of files and sandpaper, I finished the shaping of the neck. I started by using measurements from my other two basses, but the final shape just had to feel right in my hands.
||The bridge, nut, and tailpiece were all
cut from the same piece of African Blackwood that I had purchased from
Cormark International, an incredibly well stocked
local hardwood dealer here in Weaverville. This material is hard and dense like ebony, but cuts
easily with sharp tools. It's just a little lighter in color than the dark,
almost black ebony often used on musical instruments, and just a bit less
oily. In many ways it seems like a cross between ebony and rosewood.
I selected a piece that was 3" x 12" x 3/4" thick. Since the largest part to cut was the tailpiece, I did that first using the jig saw, then I set it aside while I worked on the bridge.
|The bridge was constructed like the
bridge on an archtop guitar, with a solid base fitting the top's contour. After cutting the base to approximate shape, I attached sandpaper to
the top of the bass with masking tape, and worked the base of the bridge back and forth to match the
profile of the top.
The saddle is adjusted in height by hex nuts on two 8-32 stainless steel screws threaded through the base. I shaped the radius of the top of the saddle to match the neck radius and set each string at a slightly different length based on observations from my other bases, so you could say this is a "compensating" bridge.
|The nut came next. After working the blank with sandpaper until it fit snugly in the slot I had cut in the neck, I reduced the height, cut it to length, and radiused the top. Then I filed the notches to the same gauge as my favorite strings: .045, .065, .080, and .105, aligning the bottom of each notch to be slightly less than 1/16" off the fingerboard.|
All the while, I was trying to imagine some creative way, using the tools I had at my disposal, to shape the tailpiece. Finally the idea hit me. I took a scrap of plywood to use as a cradle for the roughed out tailpiece. Then, with a metric nut and bolt, I changed the lockdown feature on the miter saw so it would act as an adjustable depth stop, and proceeded to make a series of cuts in the underside to create its concave surface. 10" circular carbide saw blade = 5" radius hollow. Nice!
Next, using the same plywood cradle to hold my work, I worked it with a sanding wheel on the angle grinder to freehand the shape of the outer side, then hit it with the files until finishing it off with sandpaper.
I had drilled holes for the ball ends of the strings before shaping the tailpiece, and had originally attempted to cut the pockets for the balls using the drill, but abandoned that method because it was too sloppy. Instead, I filled my mis-cuts with black epoxy and with the tailpiece in the same plywood cradle, used the router with a 1/4" straight flute bit to cut the pockets for the balls on the underside. Nice cuts!
||Time to connect the endpin. I had bought
a combo endpin jack strap button from Stewart MacDonald, and drilled out the
threads so I could slide a 3/8" stainless bolt through it. The bolt threads
into the brass insert in the tail block.
Because I had used a center sound post brace, I wouldn't be able to have my endpin retract inside the bass, so the endpin would be external.
The parts to hold the endpin are plumbing fittings, with the final one being a 3/8" compression fitting. The brass ferrule that comes with the fitting slides nicely onto a piece of 3/8" aluminum rod, and makes a tight connection for the endpin.
|At long last I was able to string it up!
It took a bit of patience to get things set up for the first time, main thing being able to adjust the bridge to lower the action far enough to be comfortable to play without having any strings buzzing on the fingerboard. I also learned that the E and G strings should be threaded into their slots on the tuning machines before the A and D strings. Otherwise it's very difficult to weave the E and G under the others.
It played nicely, and it sure was rewarding to hear the music of that wooden object come alive!
I played for an hour or more that evening, and set the bass in a room adjacent to our bedroom, then went to sleep myself with those pleasant sounds in my head.
||Just before midnight, my wife woke me to
say that she thought she had heard the bass fall over (silly me for leaving
it standing up leaning against a chair!). I went into the next room and
found that the body was still standing just where I had left it. The
loud noise she heard was the neck breaking at its joint with the heel and
the clatter of the neck as it separated, propelled by the tension on the
strings. All I could do was shake my head, chuckle to myself and resolve to
deal with it in the morning.
To make the repair, I drilled through the fingerboard and down into the heel, placing two 3" stainless steel screws as permanent reinforcement and re-glued the heel. John Yurko, you were right! This indeed was a weak spot in the design!
I plugged the surface with short pieces of 5/16" hardwood dowel, and these serve as the dots to mark the octave position on the fingerboard - how convenient!
During this repair, I also noticed that the poplar binding was was becoming indented. It was too soft to take the tension of the tailgut crossing it, making obvious the need for a tailgut nut. I carved one from a scrap of the African Blackwood.
|Repairs made and multiple evenings of
practice under my belt (this is my first fretless, and I still have to be
careful about proper intonation), I was ready to take it out for a test
drive. I played about half a set with it at a local gig. It played very well
- I had it miked with a Sure SM57 going into the PA. The small venue has no
monitor system, so it was difficult to hear myself, but the audience thought
it was very cool!
Two nights later, while practicing again at home, during a break, I leaned the bass up against a chair. I don't know if one of the cats knocked it over or I just didn't balance it well, but it fell, and wouldn't you know, the neck broke at the same joint with the heel again! (Whoa, John Yurko!) Of course, the reinforcement screws kept the parts from becoming projectiles, but it separated at the same spot nonetheless.
This time I switched out the flathead stainless screws for panheads. Apparently the tapered seat of the flathead had allowed the screw to be drawn down into the heel a small fraction of an inch, but now, the flatter seat of the panhead screw won't allow for any movement. To fit the screws into the same hole in the fingerboard, I had to reduce the diameter of the screw head (I had done this previously for the flatheads, too). Lacking a lathe, I chucked the screw up in the drill press, and rotating at slow speed, used a mill file to take off the excess material, checking with a micrometer till it was done.
Then I added a third screw from the inside of the heel going up into the neck at an angle that would better counter the tension from the strings. Imagine gluing this back together while maintaining correct alignment as each of the three screws is tensioned!
||I also took this opportunity to improve the design of the tailgut nut. The previous improvement had been a fairly thin piece, shaped to cover the binding and raise the tailgut above the surface of the bass (the desired result) while protecting the binding, but this part was too weak. I replaced it with two pieces: one to substitute for the damaged binding and the other to be the actual nut raising the tailgut off the surface. The first piece was inserted and glued directly in line with the binding, and the latter was glued and fastened with two stainless steel brads directly to the top.|
|Now that everything was apart again (gee,
I sure am glad I used a bolt-on neck!), I put two coats of amber shellac on
the neck and then finished it off with two coats of clear lacquer.
One more minor change (thank you Phillip Barker), was to the angle of the neck vs the body. A small wedge at the heel of the neck raised the string height over the body, adding a little more pressure on the bridge, also improving the volume.
The machines are from Stewart MacDonald and are identical in construction to those that Fender uses on some of their basses. By the way, if you get a set of these that is set up Fender-style "like normal" - all the same for the standard right handed bass, you can remove the screw holding the large gear, pull the worm gear out and reverse it, then reassemble the machine, so you can have left and right pairs (or you could even make a whole set of left handed machines if you are making a custom lefty neck). Very easy!
The bridge was another area I sought to improve upon. I
knew the solid base of my bridge was located directly over my bracing
system, and had originally thought that this would be the best way to
transfer the vibration of the strings to the resonant body of the
instrument. By changing out the one-piece base for individual feet,
the top became more resonant.
More changes to the bridge design are coming...
|Now, with everything adjusted again, I
stopped by at Mark Appleford's house to show off, and Mark took the first photo of the
I later paid a visit to The Music Center, and Corey set me up with a clip-on piezo-electric pickup. Clipped to the bridge, it worked pretty well while playing with Billy Owens at open mic that evening at Blue Mountain Pizza.
Now, I hadn't set out to build an acoustic-electric bass, but I also recognized the need for being able to plug it in anytime we'd be using a PA at a gig. My previous experience using the SM57 to mic it wasn't ideal, so the idea of a pickup became much more appealing.
||I bought another piezo-electric pickup
for about $12. This one had a suction cup to hold it on the instrument, but
I found that the suction method wasn't very reliable. I opened the case up
to find this little disc about the size of a nickel with the piezo element
I cut the cord to about 18 or 20 inches and soldered it to a thick panel, 1/4" female phone jack, the Switchcraft type designed by Fishman to be tightened from the outside of the instrument (available at Stewart MacDonald); I bought mine from Musician's Workshop, our other local music store.
I had to countersink the jack to make it work with the thickness of my end block, but it came out nicely - just about flush with the outside.
I stuck the pickup to the underside of the top with an adhesive putty, and clamped it for an hour or so to be sure it would stay.
|Now that I have been playing this bass at
some of my gigs, I am often asked what this instrument is and what it
is called. I call it a "Bassirelli." The name is as much of a hybrid
as the instrument itself. The body shape, the string attachment method, the
peg, and the upright playing position all resemble the low register
instruments of the violin family, so the word "bassi" which means low in
Italian, is the beginning of this compound word. The shape of the neck, the
flatter fingerboard radius, and the style of the bridge all resemble the
bass guitar. The fact that it's also fretless honors the bass player
who has been such a great inspiration to me, Kenny Passarelli. In the late
winter and early spring of 1974, Kenny would stop in to jam at the Maui
Belle in Lahaina with Catapult, the band I played with in the early and mid
1970's. Kenny had a bass very similar to my Fender Precision Bass, but his
was fretless, yet when he sat in with Catapult he often played mine. So the
"relli" portion of the word "Bassirelli" is my tribute to Kenny Passarelli.
If I'm not mistaken, Kenny had been playing the fretless bass guitar
years before Jaco Pastorius tore the frets out of his Fender Jazz
I'll update this page as I continue to make revisions to the bass, but here's a photo of the project, taken while I was still experimenting to find the sweet spot for the pickup (notice the silvery button on the surface of the top between the f-hole and the bridge). This photo was taken just before the photo in the frame above where I used the blue adhesive putty to attach the pickup. I had tried several adhesives before I settled on the Blue Stik, hot glue among them. The problem with hot glue was its short working time and the difficulty of access through the small f-holes. More later - enjoy!