Double Bass recalcitrant flatback

[Matthew Tucker]

Please remember to give us a complete report on the differences in tone, color of sound, depth, volume etc as compared to the last Bass you made.

The bass is a different model, different wood and different size and different arching to the other one, so any differences in tone will of course never be able to be attributed to one thing, or another.

I'll only be able to have a stab at that if I make the same model twice and change ONE variable!

Back and ribs - quartersawn eucalyptus regnans (Tasmanian Oak)
Top - quartersawn western red cedar
Neck and scroll - blackheart sassafras
Bracing - tight grained WRC

Measurements for this one are

Body 108
Upper 46
waist 39
lower 66
ribs 18 at break
19 at endpin

Here's an action shot with my wonderful gluepot in a cameo role in the bg

 

[KSB - Ken Smith]

Thanks for the #s but I have a few questions and comments.

First off, the 108cm top, how are you measuring that? That is only about 42.52". Small 3/4 IF you are measuring to the Tips. Measure all the wood and also, measure the Back up to the Button and including the Button as well. This gives a playability point of view as well.

Ribs I assume are the actual Ribs and not including the Top and Back plates, correct? Either way, it's nice to see the confidence in building that you don't need deep Ribs to get a big sound. My Cornerless is 7.75" (19.7cm?) and my other loud Bass was the Dodd at only 7.5" (19.05cm?). My Loveri is a cut down Bass with the Rib depths being between the two Basses mentioned above and quite loud and punchy as well.

Measurements for this one are (in both languages now)

Body 108 (42.52")
Upper 46 (18.11")
waist 39 (15.35")
lower 66 (25.98")
ribs 18 at break (7.09")
19 at endpin (7.48")

If you ask me, this measures up to be a small to medium sized 3/4 Bass. Was that your intention?

Is there a particular Model you followed for this or a combination of Models?

 

[Ken McKay]

Hi Ken, I've done it on cello ribs a couple times, and it worked out really nice. And as far as bases, I did it to a school orchestra bass about four years ago, to bring up a sunken ply wood top that really should be tossed in the bin, for all the things wrong with it. That worked out better than I expected.

I took the top off, used some moisture and a heat gun to try to get it back in shape. After that I let it sit for a week or so with a buch of weight on it. Then I glued linen strips all width wise across the top, with really strong h-glue on the kitchen stove. I was surprised how much the shrining linen thing helped. that's why I mentioned it here.

Haven't done it on a flat back, But I have no doubt it would contribute to the cause, even if just to hold the shape after the other tricks are used.

Hey ken, since you're up in the snow belt as well, do you find Februarys give you the most trouble with wood movements? for me, I think I'm seeing a trend that this month always sucks for making center joins, or watching fresh carved plates potato chip in front of my eyes.

Yes, I am up to my eyeballs in those kinds of repairs. I try to do my back bracing while it is this dry season because I know things will not get worse.

 

[Matthew Tucker]

Is there a particular Model you followed for this or a combination of Models?

Ken, remember I am making a copy of Stefano Sciascia's bass. Not a true copy by your standards as I am using different woods and I am not copying the scroll religiously with all its fancy carving and I haven't any info about the internal bracing or arching, other than what i can see from the photos Stefano sent me, and the back view with all those rusty screws through into the braces ...

small-medium 3/4? I don't really care what to call the size. It will be what it is, a thin ribbed cornerless bass with a 41 1/4" mensure.

i measure body length just as you state, from bottom of tailblock to the highest point of the front of the neck block. The top block on this bass is sitting square and the neck heel will probably rake back a bit.

i think i may have cheated an extra 5-6mm in rib depth on the measures I gave before. I haven't really measured much after initially making the mould, as it all becomes a movable feast when you start building. Particularly with a cornerless bass, the tricky thing is there's nothing to hold the waist into the mould, and I had to glue on some little towers on the inside and keep the waist pulled together with a wire.

I am using curtate cycloids as an arching guide on this bass, pure as i can to begin with and then I'll let my instinct take over for final shaping. Thicknesses will be done probably along the lines of the thicknesses I used for the other bass but i might try a bit thinner in the inflection area.