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!

Carving the Five-string fiddle Back Plate

Five-string fiddle Inside Complete

Before I could prepare the back plate of this five-string fiddle, I had to complete the rest of the corpus (body of the violin:) First, the inside willow blocks and willow linings had to be tapered and shaped so they are completely smooth. Then, the back of the entire corpus (including the heel of the neck) has to be leveled, so that it will lie flat on the back plate. So, here is the main part of the 5-string violin, with the interior clean and smooth, and the back leveled and flat:

Five-string fiddle Inside complete, and back leveled.
Inside complete, and back leveled.

 

Beginning the Back Plate

I clamped the corpus flat on the back plate billet, then traced around the ribs, using a small washer to establish the correct rib overhang. Then I corrected the corners, using a straightedge and a series of circle patterns. Finally, I cut out the plate “footprint”, and began the arching process. Oregon Big Leaf Maple is a relatively soft maple, but it is still a good deal harder and tougher than Sitka spruce, so the back plate is a lot more work to carve. Here is the beginning:

Beginning Five-string fiddle Back Plate arching.
Beginning Back Plate arching.

In the above photo, the back plate is sitting in a work cradle, so that it will stay in place while I carve it. The Ibex plane in the photo has been slightly modified, to add the palm-fitting handle. This reduces the stress on my fingers and transfers the force to the palm of my hand as opposed to my thumb and forefinger. (To Ibex plane-owners: you will observe that I have removed the adjusting screw and reinstalled it upside down to allow insertion of the maple handle.)

I have been on vacation for two weeks, which has allowed me to accomplish more work than usual, in a shorter period of time. I go back to my regular job, on Monday, though, so things are about to slow to a crawl. (Sorry…that’s life. :-))

 

Thanks for looking.

More 5-string Fiddle Progress

Five-String Fiddle Progress

(Further progress on building a custom-made 5-string bluegrass fiddle.)

Neck Set

The neck was ready to set into the neck-block, late last night, but I had reached my physical limit. So, today, I prepared both the neck and the garland, by ascertaining that all angles and dimensions were correct, and then laying out the shape of the neck mortise on the neck block of the garland.  This is a critical step in violin-making and always raises my blood pressure a little, as I know that, if I make a mistake, it will require serious rework to get back to a usable status.

However, this time, the job went pretty smoothly, and I was able to set the neck in a fairly short time. One thing I do a little differently than I was originally taught, is that I set the neck before installing the maple back plate. This allows me to achieve a good fit with the rib garland and neck block, and not have to worry about the fit against the back plate button. Then I saw off the stub of the neck heel, and plane and file it flush with the rib garland. After I remove the mold and add the back linings, I will level the back of the garland, and be ready to trace the back plate shape.

 

Five-string fiddle neck Set Complete.
Neck Set Complete: still have to remove the neck-heel stub.

 

Here is the completed corpus (Sitka Spruce top plate and Big Leaf maple ribs still on the mold) with the wild-grain Big-leaf maple back plate billet.

Completed Corpus of Five-string fiddle with Back Plate Billet.
Completed Corpus with Back Plate Billet.

 

Mold Removal

So, the next step was to remove the plywood mold. This is another stressful step because it involves literally using a hammer and chisel, to break the glue-bond between the blocks and the mold, so as to release the garland from the mold.  I used to have a difficult time doing this, because occasionally a drop of hide glue had seeped between the rib and the mold, and anchored the fragile rib material to the very solid mold. The likelihood of breaking a rib at that point became nearly 100%. Eventually, however, I learned to liberally coat all the non-gluing surfaces of the mold with candle-wax (paraffin,) by vigorously rubbing a candle over all the areas I felt were likely to get a drop of glue on them.

The result today was that, when I removed the mold, it went smoothly, and I could see a place where glue had definitely intruded but it had dried with zero adhesion to the waxy mold. (What a relief!)

Five-string fiddle mold removed, ready for back linings.
Mold removed, ready for back linings.

Installing the Back Linings

The linings are important for two reasons: they strengthen the fragile rib-edges, and they triple the gluing surfaces between the rib-garland and the front and back plates.

So, I cut the mortices in both sides of each of the six blocks to receive the lining strips, and then inserted the linings dry, to get a perfect fit.

Afterward, I removed each lining, one by one, coated them liberally with hot hide-glue, and re-inserted them, clamping immediately with small spring-clamps.

Five-string fiddle back linings installed, glued and clamped.
Back linings installed, glued and clamped.

Shaping Blocks and Linings

If you look closely you can also see, in the above photos, that I had trimmed the blocks on the front side, before removing the mold. After the glue is dry on the back linings, I will also trim the back side of the blocks, to achieve a smooth, curved surface on the interior of all the blocks. At that same time, I will taper the linings so that they are very thin on the edge toward the middle of each rib, but still 2 mm thick at the edge where they will contact the back and front plates.

After that, it will be time to level the back surface of the entire corpus (garland and neck-heel) so as to fit tightly against the back plate billet. Then I can trace the final shape of the back plate, cut it to shape, and get going on completing the back plate.

For now, I am satisfied to allow the glue to dry, and take the rest of the evening off.

 

Thanks for looking.