What follows is construction information for a handsome 4-string 
tub-bass built in a manner similar to mine -- one difference 
being the use of an oblong galvanized tub instead of a round 
one. As received from Bill, this information included several 
photos which could not be included here in their original 
resolution due to my lack of available webpage space. I was able 
to squeeze in one low-resolution photo collage of Bill's 
instrument that hopefully will at least give you a rough idea of 
what Bill's neat instrument looks like. Dennis Havlena

Tue, 16 Jul 2002
The "Rub-A-Dub-Tub"(Washtub Bass)
By Bill Koch

The washtub bass that I built was inspired by Dennis Havlena, 
who has a great web site about numerous, home made musical 
instruments that he designed and built. Check it out sometime:
Dennis had some drawings, plans, and pictures of a washtub bass 
he made. His design used a maple neck attached to a circular #3 
galvanized tub. I decided to make my own washtub by improvising 
upon his basic design. The finished product turned out much 
better than I envisioned, both in appearance and sound 
(See pictures 1 and 2).

The tub I used for the bass was a #3 oblong galvanized tub ($20 
new). I removed the handles from each end of the tub by hooking 
the handle over the "ears" of a bench vise and opening the vise. 
You could probably use some strong pliers to do the same thing. 
I cut a bunch of small pieces of pine 1" x2" board and glued 
them to the inside of the washtub using Liquid Nails 
(construction adhesive). I made sure that the top of each piece 
of wood was one-fourth of an inch below the top rim of the 
washtub (See picture 3). If you cut the pieces at a slight 
angle, when mounted to the slanted side of the tub they will 
have a top surface that is roughly parallel with the front that 
will be glued on later. You could use epoxy instead of Liquid 
Nails for the same purpose.

To make the front of the bass (the table), I turned the washtub 
upside down and traced it onto the back (rough side) of a 2' x 
4' sheet of quarter inch birch plywood ($10). Alternately, you 
could chalk the top and transfer it to the wood. To take into 
account the width of the lip of the washtub, you need to cut the 
wood about one-fourth of an inch INSIDE the tracing. The saber 
saw blade leaves a jagged edge when it cuts, so be sure to cut 
with the good side down (giving it the smooth edge after 
cutting). Then sand the edges of the top and fit it into the tub 
so that you have a snug fit inside the tub, fairly flush with 
the lip (See picture 4).

I used a piece of 1" x 4" pine board for the main support. If I 
did this again, I would use hardwood because the pine is not 
strong enough to resist bending under the pressure of the 
strings. I cut a rectangular hole at the top end of the tub to 
fit the main support through the tub so that the neck end sticks 
out about 7". The top edge of the hole should be about one-half 
inch below the rim of the tub. If you cut three sides of the 
hole in the tub, it leaves you a metal flap that can be bent and 
then screwed into the main support. Later, the neck of the bass 
is mounted to the part of the main support that sticks out. 
Also, I wedged a wooden block at the top end of the inside of 
the tub between the bottom of the main support and the tub 
bottom. That block is used to mount the screw eye bolt (using 
washer and nut) that will hook to the turnbuckle.

At the foot of the tub, I attached the main support using two 
wood screws from outside the tub into the wood. The main support 
was mounted about one-half inch below the rim of the washtub, 
which gives adequate clearance from the top even when it flexes 
during playing.

Also at the base of the washtub, I mounted a wooden block using 
four wood screws. The block wedges between the bottom of the tub 
and the main support. The block serves two purposes. First, you 
need to drill a hole through both the tub and the block to mount 
a screw eye (with a washer and nut tightened from the inside) to 
which you will later attach the end piece for the bass. The end 
piece holds the bottom ends of the bass strings. Also, you need 
to drill a hole into the block for the endpin. I used a hardwood 
table leg about 14" long for the endpin; it screws into the 
block via a threaded T-nut mounted into the wood block.

By far, the most difficult part of the project is cutting and 
shaping the neck/fingerboard of the bass. I used a piece of 1" x 
4" x 8' length of red oak ($15). No doubt it would be preferable 
to use some other hardwood that is less grainy such as "rock 
hard" maple or rosewood. First I cut the oak board into two 
pieces 35" long each. I overlapped them by 25" so that 10" stuck 
out at each end. Then I glued them together and clamped; that 
way you have 1.5" thickness for the neck/fingerboard. The top 
board becomes the fingerboard and the bottom board is the neck
(See picture 5).

The washtub bass requires the usual sound post and bass bar 
that you'll find inside any upright double bass. I took a 
small square block of wood (2" x 2" x 3/4") and drilled a hole 
into it to fit a piece of dowel (broom stick) for the sound 
post. I glued the block to the bottom of the tub (Liquid 
Nails), and then I stuck the dowel into it. You need to 
position it so that it will contact the top (the table) just 
below where the foot of the bridge on the G string side will 
be. I also put a thin (1/4") strip of wood between the top of 
the sound post and the underside of the top to distribute the 
pressure. The bass bar that I used was simply a piece of 1" x 
3/4" of pine about 18" long. You need to glue and clamp it to 
the underside of the top (table) in a lengthwise direction 
roughly where the other food of the bridge will be (the E 
string side). The sound post and the bass bar support the 
table and keep it from collapsing when under the pressure of 
the strings. They have to be finished and in place before you 
actually glue down the top to the washtub (using Liquid 
Nails). Finally, after the top was mounted, I used clear 
silicone sealer all around the rim of the washtub to seal the 
top to the tub and fill the crack.

The fingerboard was 3.5" wide at the bridge end and 1.5" wide at 
the nut. I used a Stanley hasp to shape it very roughly (to make 
its surface gently rounded as you go to the edges) followed by 
the use of a long wooden sanding block (3 feet), which must be 
perfectly flat. You can staple sandpaper to the block or use 
spray adhesive to hold the sandpaper in place. The sanding is 
very tedious but must be done carefully to avoid flat spots. You 
sand lengthwise with the fingerboard (going with the grain of 
the wood) to make its surface gradually curved toward the edges.

The same method was used to shape the neck, but the curving is 
much more severe. The best thing to do would be to look 
carefully at the neck of an upright bass to see the shape it 
should have. The last 8" of the neck at the top end are made 
into the head of the bass where the string tuners are mounted.

The tailpiece was cut from the same red oak board. It was 10" 
long, 3.25" wide at the bridge end and 1.75" wide at the tail. I 
shaped and curved it slightly and smoothed the corners. I 
drilled four holes needed to insert the ball ends of the strings 
and also cut a thin slot about 1/8" wide coming out of each hole 
for the strings to slide into their mounting position. Also, I 
carved a shallow slot about one-half inch from the bridge end 
and inserted a piece of copper wire for the strings to rest on. 
I just bent about 1/4" of the wire at each end and inserted the 
ends into small holes drilled into the tailpiece.

To attach the tailpiece, I used a short length of braided 
aircraft cable from the hardware store and some cable clamps 
(about 1/8" diameter). I threaded the cable through the two 
holes drilled into the bottom end of the tailpiece. The two ends 
were clamped to the screw eye bolt at the bottom of the tub. My 
buddy, Ward Walker used a Dremel grinder to carve my last name 
into the tailpiece in a scroll design similar to that used on 
the Kay double bass. Many thanks also to Ward for taking the 
digital photos used here and sending them to me as jpeg images.

I cut two F-holes into the table (front) of the bass. From 
center to center, the F-holes are 6" apart toward the top and 
14" apart toward the bottom of the bass. At the top, the holes 
are about 6" from the edge; at the bottom, the holes are about 
2" from the edge. The curved slot connecting the holes is 3/4" 
wide at the widest part, but it tapers down to about 3/8" where 
it joins the holes. The bridge will be mounted about 15 inches 
down from the top of the table, so the F-holes should be cut 
accordingly. You want the bridge to be positioned about in the 
middle of the F-holes.

The bridge also was cut from the oak, but you need to be sure 
that the wood grain runs horizontally when looking at the bridge 
as it stands up. My bridge was 4.5" wide at the base and 4.25" 
wide at its top. Its height was 3.25". The slot along the foot 
was 2.25" long. Two holes of 3/4" diameter were cut toward the 
bottom of the bridge. The two holes at the top were 1/2" in 
diameter and then joined by cutting a slot (See picture 6).

The turnbuckle that I attached serves two purposes. First, it 
prevents the main support (and neck) from bending under the 
string pressure. Second, it allows the player to adjust the 
action of the strings (how far the strings are above the 
fingerboard). If the strings are too close, they will buzz when 
played. If they are too far above, the volume will increase, but 
it becomes more difficult to play (it takes lots of strength and 
effort to press them down to make a note). The turnbuckle I used 
had a body that was 4" long, plus you add the length of the 
screw eyes, etc. I mounted a block of wood inside the tub to 
mount one end of the turnbuckle using an eyebolt. The other 
eyebolt was mounted to the back of the neck (See picture 7).

The neck/fingerboard unit was mounted to the main support via 
six wood screws, glue, and an oak wedge (used to get the proper 
angle of the neck). The wedge was 7" long, 1/8" thick at the 
head end and 3/4" thick at the other end toward the washtub
(See picture 7).

The strings that I used were Corelli Bass strings for a one-half 
sized bass, which were a perfect fit. The Corelli brand is 
Italian, but the strings are made in France. I ordered them from 
Quinn Violins on the internet for about $120. Sorry, but there 
is no substitute for good quality, commercial double bass 
strings (even the cheapest cost at least $75). I used standard, 
nickel plated electric bass tuning machines available at most 
music stores (about $25).

Here's a picture of me (Bill Koch) playing the washtub bass in 
the beer garden of Player's Rretaurant near the University of 
Texas at Austin campus (See photo 1).

Click here to return to Dennis Havlena's webpage.