Setting up the Bass

Instrument Set-up

The Plan:

Fit and install the End Pin. (Already done on this instrument.)
Fit and install the Saddle. (Already done on this instrument)
Fit and install the Tuners (in the case of a double bass, that means “tuning machines.” Already done on this instrument.)
Fit and install the Soundpost. (already done on this instrument.)
Fit and install the Nut, file the string slots to the correct depth in the correct places.
Establish the correct length for the Tail-gut (or tail-wire in this case) and install it.
Fit and install the Bridge, filing the string-slots once the height is correct.
Install the Strings.
Play for sound adjustment, string clearance adjustment, etc.

End-Pin

On violins and violas, the end-pin (usually called the end-button) only serves as an anchor-point for the tail-gut. But, in cellos and double basses, it also must serve as a height-adjustment, so that the instrument will rest at the correct height for the particular player. In this case, I had chosen an Indian Rosewood plug with a tubular steel end-pin fully adjustable and locked by a thumb-screw on the bass side. I installed it earlier, so here it is, without details about shaping the plug or reaming the hole:

Saddle

I cut my saddles with a large radius on each of the upper corners, where the saddle is cut into the front plate. There is a strong likelihood, historically, that cracks will eventually develop, emanating from the corners of the saddle. They are so common that they have a name: “saddle-cracks.” There are two ways to try to avoid such cracks:

The first is to make the mortise for the saddle (the part cut out of the front plate) a little wider than the actual saddle, by maybe a millimeter or so, so that, when (not if) the front plate shrinks during dry weather, it will not find itself up against the unmoveable saddle, and be forced to crack, to allow for the shrinkage. This is a good practice, and I try to follow it.
The second is to make the saddle with sound corners so that there is no “notch” in the plate at the “corners” of the mortise, but rather a smooth rounded curve, which eliminates the stress-riser and minimizes the chance of a saddle crack in the first place. (Round discontinuities essentially do not cause stress risers, hence, do not cause cracks.) I always do this, (since about my sixth instrument) and will continue to do so.

I already explained all this, including the purpose of the saddle, in a previous post. Suffice it to say that this part is already completed.

Saddle with round corners, to prevent saddle cracks.

Tuning Machines

There is a wide variety of choices for tuning machines for a double bass. Some are better than others, some fairly plain, but fully functional and reliable, others beautifully engraved or ornate in some other way, and understandably far more costly. Someone had to spend the time and money to do all that “pretty stuff,” so, if you want that, you gotta pay. I chose plain but functional. (They are pretty, too, but not fancy.)

Rubner tuning machine for a five-string double bass. — Rubner tuning machine (one of five.)

At any rate, they are already installed on this instrument, as of my last post:

Tuning machines installed on five-string double bass.

Soundpost

The soundpost is a “dowel,” usually of fine-grained spruce, that spans the gap between the inside of the front plate and the inside of the back plate, just south of the treble bridge-foot. My understanding is that it transfers the vibration from the front plate to the back plate, and “couples” the two plates so that they work together to make the sound from the vibrations created at the strings (whether by bowing or plucking.)

There may be (probably is) more to this function: It is an important enough part of the set-up that in some languages, the soundpost is referred to as the “soul” of the instrument, and it is definitely one of the most important adjustments that can be made. It is held in place simply by the compressive force transferred through the bridge by the tensile stress on the strings. Adjusting the position of the soundpost has a profound effect on the character of the sound the instrument can produce.

I already installed the soundpost, but I fully anticipate that I will continue to adjust it as the instrument settles in, in an attempt to produce the best tone, volume and balance that I can achieve in the sound of the instrument.

Soundpost installed in a five-string double bass. — Soundpost installed, in preliminary position. Adjustments will be made from here.

Nut

The nut is the transverse piece of hardwood (usually Ebony, but in this case Ipé, ) across which all the strings are resting, directly above the fingerboard. It serves as a positive stop for all five strings, so that the strings are not in actual contact with the fingerboard when the player is not fingering a note, but are suspended about 0.5 mm above the surface of the fingerboard. the idea is that an easy touch from the player’s finger should put the string in contact with the fingerboard at the correct position for the desired note. The nut is glued to the neck and fingerboard, usually, but in reality, it is held in place by string tension, and the glue is “just a formality.” (I glue them so that they can’t fall off and get lost, during transport or a string change.)

I carefully laid out the string locations, so that they are spaced equidistant, center-to-center, and then cut the slots for the strings using first a small razor-saw, and then a round file of the appropriate diameter for the string in question.

Nut installed and slots filed for a 5-string Double Bass. The corners will be rounded later.

Tailpiece and Tail-wire

I chose to make the tailpiece of Ipé wood, to match the fingerboard, nut and saddle. The tailpiece fret (transverse bar forming a positive “stop” for all five strings) is also Ipé, and after being heated and bent, it resisted being glued. I eventually took it off entirely, scraped off all the failed glue-layers, washed it down with acetone to remove the oils in the wood, and reglued with epoxy. But this time, I anchored it with six small brass rivets. It is permanent, now! (Besides, I like the look of the shiny little brass rivets!)

I also attached the tail-wire; a 1/8″ diameter stainless-steel aircraft cable. I established the length so that the distance between the nut and bridge would be as close as possible to being in a 6:1 ratio with the distance between the bridge and the tailpiece fret.

Completed tailpiece assembly for a five-string double bass.

Bridge

I chose a bridge blank that was tall enough to serve with the projection angle I had already established, and wide enough to comfortably accommodate five strings.

I fitted the bridge feet to the surface of the bass front-plate, so that it would have an airtight fit when placed between the inner “notches” on the f-holes, and centered over the centerline of the plate.

Once the fit of the feet was established, I marked the bridge for the approximate height, hoping to achieve a string clearance of about 11 mm above the end of the fingerboard, but erring on the side of “too high.” (I can’t very well “put it back,” if I remove too much wood.) I then marked the locations of the strings, giving them 25mm from center to center. I filed the string slots, so that the strings would stay put when installed, and I went ahead and installed the strings.

As it happened, I ended up with about 14mm under the B-string, ranging to 12 mm under the G-string…way too high. No problem: I simply re-marked the bridge, this time having a better idea of where things would line up, re-cut the top of the bridge, re-filed the string slots, and tried again. This time I had 11mm under the B-string, and 6mm under the G-string, with the strings in the middle at about 8mm. That is acceptable, so I finished trimming excess wood from the bridge, tuned up the strings, and I was ready for the final adjustments for sound.

Five-string double bass, set-up and ready for final adjustments. — Five-string double bass set-up and ready for final adjustments.

It is quite a relief to me to finally have this instrument nearly complete. It was actually begun several years ago; but it was set aside for a variety of reasons, and only resurrected as a project, this Spring.

The sound, at first set-up, is satisfactory, but I hope to achieve a better balance, more volume, and better clarity as the instrument “settles in’ a bit, and with subsequent adjustments of the soundpost. But for now, I’m happy with it. It looks good and sounds good. For a brand-new instrument, that is a good start.

Completed 5-string double bass with cello in the background.

So, for now, that is it! There are a few “finishing touches” and re-touch of varnish, etc, as well as the aforementioned sound adjustments, but the bass is essentially complete!

I hope to make all the necessary adjustments, and then find a player or two to “test-drive” it for me, since I am not a player, and can’t do it justice.

I will post the “verdicts” from those players when they happen.

Thanks for looking.

June 26, 2020

And, occasionally, Gifts!

Gift Box

Why a box?

An elderly couple of friends gave me a large pile of highly flamed “fiddleback” maple, hoping I could build fiddles of the wood. This was Big Leaf Maple wood that the woman’s father had salvaged specifically because of the beautiful grain, perhaps fifty years ago, while making wood to heat his home.

Unfortunately, the wood turned out to be riddled with worm damage so that most of it is unusable. I felt bad about it, because she had hoped, all through the years, to have a box or something made of the wood, and now it seemed to be lost.

I had just repaired my bandsaw, though, while in the process of building the five-string double bass, and was busy cutting up billets of violin-wood to see what I really had that would be useable. I salvaged a few pieces of their maple wood that (maybe) could make a violin, and enough thin slices that I thought I would try a box for her.

When most people think of a box, they are thinking of a rectangular enclosure of some sort: but, I’m a violin maker! So…I bent the wood into an oval, and went from there:

There was not enough solid wood to do very much, so the heavier sections are from a different tree; one cut from the yard of my wife’s family home.

Gift box showing bent body, inlaid top, solid base and lid.

I inlaid the fiddleback maple section about 3 mm thick, into the lid which was also flamed maple, but not as spectacular. I trimmed it with purfling left over from the building of the five-string double bass.

The sides were only a little over a millimeter thick and bent around a hot iron made for that purpose. But they would be too fragile, if that was all that was there, and there would also be no secure way to fasten them to the base. So there is a 4 mm raised section glued to the base and the sides wrap around that “plug.” I added a 5 mm thick ring around the top, the same size as the bottom plug, in order to reinforce the upper edge.

Then I inlaid a 7 mm wide by 2 mm thick band of bent willow wood into the lid, positioned so that it fits cleanly inside the upper ring. As it happens, the lid fits perfectly in one direction, but if you turn it 180 degrees, it is very loose. So I stamped my name in the base and the lid: when you open the lid, if both are readable or if both are upside down, then the lid will fit.

I varnished the bentwood box pretty much the same as I do my violins, and delivered it the following Saturday.

Both the husband and wife seemed quite pleased, so I am happy too.

Thanks for looking,

May 11, 2020June 2, 2020

Back to the Bass!

New Project? Nope! Not really!

Picking up where I left off:

This is not really a new project, but rather one that was “tabled,” for lack of better term…work was suspended until a better set of circumstances emerged.

I built the mold for this bass in 2015, began bending ribs in 2017, with a woefully inadequate bending iron, and a great deal of frustration.

A commission came in, so I set aside the bass, to work on the cello, and never came back to it…so it sat in the corner of my workshop silently sneering at me every time I looked that way.

But! Since I was laid off from my job, where I had worked for 33-1/3 years, in January, I am catching up with some projects and able to face others with new eyes.

Here is the five-string 16-1/2″ viola I am just finishing up, balanced on top of the bass mold:

Large viola with five-string double bass mold. — Large viola with double bass mold.

Once I had the bass mold up on my bench again, it was easier to confront the problems, rather than avoiding them.

The New Bending Iron

The first thing I needed was a new bending iron. A fellow I met online, John Koehler, a fellow bass maker, told me how he built his bending iron. So I followed his lead, and built a new bending iron:

Homemade bending iron, enabling me to bend the ribs for the 5-string double bass. — My homemade bending iron.

It is a section of exhaust tube, welded to a piece of angle iron, so that I could clamp the apparatus in a vise. Heat is supplied by a 550-W electric charcoal briquette lighter, controlled by a 600-W dimmer switch. It took a little trial and error to get it set up correctly and to calibrate it, but it turned out to work very well! (What a relief!)

Bending the ribs

Bending the remaining two Big Leaf Maple ribs was nearly effortless, and took about ten minutes, tops, not counting waiting for the tube to heat up.

Lower ribs bent to approximate the mold shape of the 5-string double bass. — Lower ribs bent to approximate the mold shape.

Installing the ribs and linings

Then I glued the ribs into the fir blocks on the mold with hot hide glue, one at a time, and affixed the willow linings in the same manner before moving to the next rib.

Treble rib with linings installed on the 5-string double bass. — Treble rib with linings installed.

Once one rib was completely secure, trimmed and lined, I rolled the bass mold over and repeated the operation on the other side.

Bass side rib with linings installed on the 5-string double bass. — Bass side rib with linings installed.

I planed the linings flush with the ribs and blocks, and the garland was essentially complete. It will require careful leveling before fitting the plates, but not much other than that.

Completed rib garland for the 5-string double bass. — Completed rib garland.

In the coming weeks, I will complete the center-joins of front and back plates, then complete the carving of the plates and the neck and scroll, and start putting this bass together!

Just as a teaser, this is the wood for the front, back and neck:

Sitka Spruce billet for the front plate of the 5-string double bass. — Sitka Spruce billet for the front plate.

Big Leaf Maple for back plate and neck of the 5-string double bass. — Big Leaf Maple for the back plate and neck.

(Notice that there is a fair chunk left over where the neck pattern does not use all the wood it is on: watch that space! )

Thanks for looking!