Posts Tagged ‘Soloist Bass’

Building a Double Bass: Shaping the Blocks

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Shaping the Double Bass Blocks

Lots of Wood to Move!

As you may recall from the previous post, the blocks on this upright bass were pretty huge, compared to what they needed to be, so there was really a lot of wood to remove.

Mold with blocks and ribs

Mold with blocks and ribs. Blocks are still way oversized, and the ribs are still straight. Gotta change all that.

 

“Kutzall” Tool

So! A drastic need makes for drastic measures. Ordinarily, on a smaller instrument, I would use the bandsaw and oscillating spindle sander to shape the blocks, but this  mold is reeaaalllly heavy (over-built, I think…oh, well, it will be removed and the bass will be normal), even though it is a soloist bass, so I can’t see trying to manhandle it around on my big bandsaw. The saw could handle it, but the table for the saw is not big enough to hold the mold steady, and I am not strong enough to just hold it up there by sheer strength…. So… what to do?

This tool (carbide abrasive disc) is something my wife bought for me a year ago (Christmas), but I had never used it much. It is called a “Kutzall”, and it tears away wood incredibly rapidly, without loading up, and without burning the wood. So I used it to remove the large rough sections, then used the plane to remove the torn surface, and finally, to shape the blocks:

Kutzall disc, with 5

Kutzall disc, with 5″ DeWalt angle grinder: Not for the faint of heart! Absolutely wickedly effective, but not as dangerous as the Lancelot tool.

 

Stanley #100-1/2 Squirrel-tail Plane

It was about 37 degrees, F, outside, but the sun was bright, so I worked outside.

Smoothing and shaping the corner block

Smoothing and shaping the corner blocks, using a Stanley “Squirrel-tail” #100-1/2 hand-plane.

 

The little plane is somewhat hard to control, because the curvature of the sole is so extreme, but, if it is sharp and if the blade is set for a very shallow cut, it works well.

sharp plane

It does have to be sharp! (Time to sharpen….)

 

Stanley # 100-1/2 curved-sole plane

Stanley # 100-1/2 curved-sole plane…for those of you who are unfamiliar with it.

 

stanley plane

I was able to shape the blocks pretty close to finished shape with the little plane, but there are some irregularities. I have another tool for that problem.

 

The bottom block was planed entirely with a low-angle plane (also Stanley– can’t recall what number.) but it worked very well, and the bottom block was easy…I didn’t use the grinder at all on this one. So here are all the blocks, pretty close to finished:

Bottom block planed with a small, flat-sole, low-angle plane.

Bottom block planed with a small, flat-sole, low-angle plane.

 

And, here you can see the finished blocks, ready for sanding:

All the blocks, ready for coarse-sanding.

All the blocks, ready for coarse-sanding. The small plane leaves ripples. The sanding tool should remove them all.

 

Homemade PVC Sanding Tool

As I mentioned earlier, the oscillating spindle sander I have would not be tall enough for these blocks even if I could manhandle the mold up onto the machine. So, I made this little sanding tool out of re-claimed PVC fittings from the “Habitat for Humanity Re-Store”, and spent more on the little can of PVC cement from the hardware store than I did on all the other materials…about $2.50 at the Habitat store. I used PVC cement to affix the abrasive cloth to the pipe, too, and bound it up with strips of plastic bag until the solvent outgassed and the cement was set.

PVC sanding block

Sanding block fabricated from four PVC fittings and a 2″ section of 2″ PVC pipe, with a little piece of wood for the handle grip. Comfortable, efficient, and cheap.

 

The homemade sanding tool worked extremely well for the small corner blocks, and did very smooth work. On the neck block I used it cross-grain, holding the tool parallel to the “trough” of the curvature, and sliding it up and down the curve. It worked well, there, too, just not as perfectly as on the corner blocks. All in all, it is a very satisfying tool.

Sanding corner blocks.

Sanding the corner blocks.

 

Sanding the neck block,

Sanding the neck block, I kept the block parallel to the “trough” of the curve, and pushed it up and down, across the grain to get a smooth surface.

 

Change of Plans

You may have noticed that, though I had planned to use Willow for blocks and linings, those blocks are not willow: the corner blocks and end block are all Douglas Fir, and the neck block is laid up of three layers of clear, vertical grain Sitka Spruce. It was a matter of availability. I do have willow for the linings, and, as that in my preferred wood when I have a choice, that is what I will use. It cuts easily, bends easily, and is very pleasant to work with for both linings and blocks.

I have really felt that I was “spinning my wheels” on this project. It is large enough that I feel the necessity to work outdoors whenever possible, but the weather has not cooperated very well…it rained nearly every day for the last month. In addition, I have been struggling with a cold or some such virus. Today I was cold in the house when the thermometer read 75 degrees, so that is not normal. I finally felt a little better, this evening, and went outside for the few minutes it took me to sand the blocks, but it has been cold out, so I didn’t stay long.

Ah, well, that’s life. I’m grateful to be back on the project again.

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Building a Double Bass

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Beginning with the Design of a Double Bass

Baby Steps: Learning to Walk

I knew a few things from having built a previous bass, but I still lacked confidence. So when the International Society of Bassists had their recent convention/competition in Fort Collins, I attended and took a few photos, and tried to observe as much as I could, so as to absorb information I badly needed.

Matthew Tucker was there, which was another reason I wanted to attend. He and I built our first basses simultaneously, but he went on to excel at making basses, while I reverted to smaller instruments for the next ten years. I  kept telling myself I wanted to build another bass, and even bought wood and patterns, etc. but it is such a huge, daunting project that I never got started.

My first bass was a “gamba-cornered” bass, modeled after an instrument by William Tarr. Ironically, when I went to Ft. Collins, that particular bass was there!  Mine was only loosely modeled after that instrument, not a true copy, but I had worked from a book by Peter Chandler, and there were photos in the book of that bass, and, sure enough, it was at that show. I didn’t particularly care for flatback basses (still don’t), so I had modified the plans and made my “Tarr” model a carved-back bass, otherwise very much like his great bass. It was only my sixth instrument, and there were lots of things I wished I had done differently, but it played very well, and was moved to Illinois with the family for whom it was made, so I never saw it again.

Tarr-model bass

That first bass. Notice I didn’t even know what the little white felt things were for… 🙂

That first bass was a nice start, but I was pretty much “flying by the seat of my pants”: I did what the book said, and called the author a few times, to get more specific instructions, but when it was done I was amazed that it actually worked well…there was virtually no planning; just muddling along and plugging away until it was done. It had an “E-flat” neck, but I didn’t even know what that meant, much less how to achieve a “D” neck, which evidently is more popular. But the youngster for whom it was built was thrilled with it, and I am told that he is still playing it today.

Choosing a Design

I had bought several plans for famous basses, and may still eventually copy one of them, but Matthew Tucker filled me in on how to design a neck to be a “D” neck, and the ten years of building smaller instruments (2 cellos, five 5-string fiddles and a host of violas and violins) gave me some practical insight as to proportion, aesthetics, and varnish. So, after seeing all the makers there at the ISB convention, and seeing the prize-winners, I decided to actually give it a go, and design my own bass, aiming for a soloist bass, as opposed to an orchestral bass.

The orchestral basses tend to be big all over, and harder to access for repertoire work, though they sound great. The one I am designing will be smaller in the upper bouts, to make it easier to play, but still pretty full in the lower bouts, and deep in the ribs, for big sound.  I wanted a more graceful scroll than the one on my first instrument, so I designed that as well, and followed Matthew’s instructions to get a “D” neck.

I spent many hours sketching, erasing, and sketching again, using 1/4″ graph paper, so that when I finally came up with something I liked, I could more easily transfer it to “engineers grid paper.” It took two 24″ x 36″ pages taped together to get one sheet big enough to work with. I transferred all my sketches to the big sheet, then used a small, needle-point awl to punch through the paper into the door-skin (1/8″ plywood) of which I would make the actual templates. Then I cut out the templates, filed and sanded them to the exact smooth shape I wanted, and coated the edges with wood-glue to add some stability. (The thin plywood is pretty fragile, but inexpensive, so I tend to use it.)

I made the F-holes a good deal larger than some instruments have, hoping for better mobility of the bridge area, as well as easy flow for air.  The f-hole template was cut from thin clear plastic, flexible so that it can be formed around the front plate to transfer the shape.  Also, this will be a “violin-cornered” bass, as opposed to “gamba-cornered”. It is more difficult to build, but I like the looks better. 🙂

I already have the maple for back, neck and sides, and I ordered European spruce for the belly and bass-bar. All I really accomplished today was the completion of the mold template, the neck and scroll template and the f-hole template:

New Templates with sketches

New Templates with sketches and tools

But– the game has begun! Now I can use the mold template as I build the actual mold, get blocks in the mold, and shape the blocks to receive the ribs. One step at a time! I will keep you posted.

Thanks for looking.

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