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Double Bass Michael Hartery's bridge

#21
Yes, unless Michael has some other suggestions that are appropriate, considering the bass' modest value...

Bob Branstetter surely seems as smart and knowledgeable as they come. Perhaps he had something in mind...

I can't imagine, as a non-luthiery woodworker, any way to get that wood out easily without pulling the fingerboard. Perhaps a very small beaver, tied to a stick...

Seriously, I reckon that if some obsessed soul had endless time/energy, they could use a scorp or some other chair making tool, working by hand, but what a hateful, endless workout! The sharpening time alone would be stunning. A person could also use a Foredom power carving tool, too, I suppose, but you have control/visibility/access issues. Plus, you'd still have to smooth out the mess...

Probably better to spend the time practicing and playing. Certainly more fun! :)
 
#24
Eric Swanson said:
So the result is that prudence prevailed in this case. We will to have wait until we need to replace the board to do the A/B scoop test.

As a cabinetmaker, I have some experience with the dynamics of similarly dicey operations. Out of respect and trust, I left it to Michael's discretion whether to proceed or "bail", at any point, based on how the board removal was going. About three inches into the process, his experience and intuition told him to stop.

I truly appreciate his willingness to explore the feasibility of the idea, on my specific bass with my specific fingerboard. While we both knew that the averages were against us, it seemed worth examining more closely. As we all know, every piece of wood and glue joint are slightly different. There was some chance that it might go easily.

I even more deeply respect his prudence, wisdom, and discretion in deciding to stop. In my book, reading the risk/reward dynamic as it evolves in real time is one of the defining marks of a smart crafts person!

The end result is that my bass still sounds much better, louder, and fuller than it did when I brought it too him. His skill and judgement with the soundpost, bridge, and endpin made a real difference.

I still play an inexpensive bass with obvious drawbacks. Now, happily, it is set up well, thanks to Michael! :)
Click to expand...

Now that you went 3 inches and had to bail means there will be trouble in the future... just re-gluing that area now has changed it from the original joint. It will eventually let go down the road, so I hate to say Arnold and I were on the same page and you guys took the chance... But...
 
#25
Mark,

Thanks again for all your generous help and insight. It has been most gracious and appreciated!

Since I consider the current board as less-than-ideal, I was willing to take the chance. My view of the board as "throwaway" tipped the balance toward trying the removal, even when considering the risks we discussed here. Michael was willing to give a potentially problematic operation a try, based on my assurances that I would accept any outcome, happily.

Whenever the fingerboard gets replaced. I end up with the scooped fingerboard I want after all!

If the fingerboard had popped off easily, it would have been good, too. I saw the attempt as win-win, regardless of outcome, since I wasn't in love with the board anyway...:).
 
#26
Eric Swanson said:
Bob Bransletter surely seems as smart and knowledgeable as they come. Perhaps he had something in mind...
Click to expand...
Since Greg (clink) brought my name into this discussion, I would like to clarify what I was discussing with him regarding his Upton bass fingerboard. I only mentioned the possibility of removing wood from the underside of the fingerboard as part of A0-B0 matching. I do this without removing the fingerboard by using several tools including a Foredom power carver with a very large carving ball that is not commonly found in woodworking stores. I also have some special wood scrapers that I made for this purpose.

IMO, removing the fingerboard and removing wood on the under side (for any purpose other than A0-B0 matching) is problematical and is something that I would not normally suggest except for A0-B0 matching.

[Before someone asks - A0-B0 matching has been discussed in detail in the past and can be found by searching the forum archieves.]
 
#27
Thank you very much, Bob Branstetter, for clarifying your approach and for your incisive contribution. I didn't know that you had written a paper on the subject...further kudos to you!

Here's one thread that you allude to above:

http://www.talkbass.com/forum/showthread.php?t=168486&page=2

and another:

http://www.smithbassforums.com/archive/index.php?t-496.html

There are several more if other folks want to re-examine them.

I suspected a Foredom would be involved, if doing the job in situ. Such a handy tool...:)

The power-carving/scraping job certainly sounds workable with the power carver. Perhaps something to pursue in the future. Or perhaps, I just wait for when I need a new board.

For now, I am extremely happy to have the bass sounding so much better than it did before. Considering the overall value/quality of my bass, this may be where we pause. All told, Michael has done great work on my instrument, bringing it to life within a budget appropriate to the bass...
 
#28
Got the bass back on Friday. What a joy it is to play now! :)

After regluing the board, Michael went a step further and flushed up some areas that had been neglected before...now everything is nice and smooth and better than ever. He also tweaked the nut and board a bit. A benefit of dealing with a small-shop luthier who has the time to pay attention to each instrument they encounter...

For my low-budget-level bass, I can't imagine it playing or sounding better. When the board finally gets replaced it will be an added bonus.

Setup with Bel Cantos at 5-8mm, it bows and pizz's evenly and buzz/slap free (unlike before). After playing around a challenged setup for these past few months, it is such a relief just to have the thing working properly!

The lovely bridge is a daily reminder of the value of a problem successfully solved. The pure joy of something working properly...

Thank you all for your help!
 
#30
Hey Jake,

Thanks for the encouragement. I wonder too. Late night musings about going at it myself...I have the tools and manual skill. The problem is the lack of knowledge and time. Interesting reading the threads about the AO/BO matching. A more exacting process than I imagined, in my ignorance.

Reminds me of when I bought a new shaper for my shop. It was installed on a heavy-duty, wood factory floor. Immediately, we began to have surface quality/vibration problems. The spindle assembly had been dynamically balanced at the plant and all components were factory-fresh.

After several drive belts and hours of head scratching later, I hired an expert to come out. I used an excellent local firm, Lindskog Dynamic Balancing, who performed beautifully.

$1000 and a day later, Lindskog's technician found that the shaper's body and that floor resonated well at exactly the same frequency. Coincidentally, the machine's V-belt drive was setting up the exactly correct vibrational frequency as the machine ran. A complementary group of elements, all vibrating at exactly the right harmonic frequency to wreak havoc on my machined work.

The vibration/defects stemmed from a combination of subtle factors, originating with the machine's spindle/pulley assembly and including the floor, the machine body, and even the spindle height. The technician advised me to either have a custom-made flat belt drive made for the machine, or to drive an oak wedge in a specific spot. I went with the wedge. It dampened the spindle assembly's pulsing, problem solved. Completely low-tech, but remarkably effective.

The point is that without precise analysis, isolating the solution would have been an endless process. Hence I am a bit reluctant to start hacking away at the underside of my board...I can certainly remove the wood neatly, but how much? The AO/BO matching seems to require a level of precision that I lack the knowledge to pursue.

Again, on my cheap bass, played by this currently amateur player, is chasing this further even sensible, or just the workings of an imbalanced obsession? Something to think about carefully...I am not making my living with this instrument. It is essentially something for me to keep my hands together with and to play out on occasionally. If the operation could have been done easily, that was one thing. The increased challenge changes the equation...

I'll hear/feel the difference when I have the board replaced. Who knows, after the dust settles a bit, perhaps I'll opt to have that done sooner than normal, just out of curiosity...:)
 
#31
Just a note to amend something I posted earlier that appears to be incorrect. While I reported what I had been told about the solid fingerboards by Upton, the following appears to be a more accurate description of their use of the flat-bottomed components.

This morning, I received a PM from Eric Rene Roy, luthier at Upton Bass. He writes,"The solid boards was an experiment after following some of the work James Ham did with Gary Karr. too expensive and difficult to get and with no noticeable gain...we went back to hollowed out boards that are a bit longer than standard to compliment the cutaway."

Apparently, it was more about Upton working/experimenting to upgrade their product, than a mere change in vendors. Thanks to Eric Rene Roy for the clarification! :)
 
#34
drurb said:
Angled legs? Please explain.
Click to expand...

There are apparently myriad models of bridge blanks available, with differing heart shapes, leg angles, cutouts, etc. The many varieties are clearly beyond my ken.

My former bridge had angled legs, rather than legs that are more perpendicular to a tangent drawn at the top table's curve (like my new bridge).

While the angled legs may be fine for a bridge with no adjusters, or adjusters that are not screwed out very far, after multiple reworkings, my adjusters were backed out of the legs quite far, especially on one side.

This combination of the leg angle, string force, and relatively small amount of adjuster left in the wood allowed the whole assembly to splay outward. While the bridge didn't collapse, the fact that the feet are sitting on a curved surface had them in a perpetual state of wanting to spread toward the f-holes.

Make two adjacent fingers form the legs of the letter "A". Push down hard on a surface (especially a curve) and feel them trying to spread. (And this is without adding adjusters, or backing them out!) Now make your thumb/first finger into a "C" and do the same thing.

The splaying was such that there were visible gaps at the outer sides of both feet. They were not in contact with the instrument's top table.

With my new bridge, no matter how far the adjusters come out, the string force is always directed perpendicular to a tangent to the top's curve (at the foot). (In other words, pointed toward the center point of a circle comprising the curve at that point).

The results, in my case, is that the feet stay in contact and the whole assembly is in a more productive, stable, and relaxed stasis/equilibrium. More foot contact transmits the vibrations more completely.

Luthiers, perhaps you can explain this better than this layperson... :)
 
#35
Eric Swanson said:
There are apparently myriad models of bridge blanks available, with differing heart shapes, leg angles, cutouts, etc. The many varieties are clearly beyond my ken.

My former bridge had angled legs, rather than legs that are more perpendicular to a tangent drawn at the top table's curve (like my new bridge).

While the angled legs may be fine for a bridge with no adjusters, or adjusters that are not screwed out very far, after multiple reworkings, my adjusters were backed out of the legs quite far, especially on one side.

This combination of the leg angle, string force, and relatively small amount of adjuster left in the wood allowed the whole assembly to splay outward. While the bridge didn't collapse, the fact that the feet are sitting on a curved surface had them in a perpetual state of wanting to spread toward the f-holes.

Make two adjacent fingers form the legs of the letter "A". Push down hard on a surface (especially a curve) and feel them trying to spread. (And this is without adding adjusters, or backing them out!) Now make your thumb/first finger into a "C" and do the same thing.

The splaying was such that there were visible gaps at the outer sides of both feet. They were not in contact with the instrument's top table.

With my new bridge, no matter how far the adjusters come out, the string force is always directed perpendicular to a tangent to the top's curve (at the foot). (In other words, pointed toward the center point of a circle comprising the curve at that point).

The results, quite clearly in my case, is that the feet stay in contact and the whole assembly is in a more productive, stable, and relaxed stasis/equilibrium. More foot contact transmits the vibrations more completely.

Luthiers, perhaps you can explain this better than this layperson... :)
Click to expand...

A little long winded Eric ... I would say you had an "A" frame bridge before, you have 90 degrees now. The "A" frames are like 87 degrees or so to the top..
 
#36
Mark Carlsen said:
A little long winded Eric ... I would say you had an "A" frame bridge before, you have 90 degrees now. The "A" frames are like 87 degrees or so to the top..
Click to expand...

Thanks, Mark! More that a little long-winded, I fear...:)

The angle obviously gets increased, though, if one side of the bridge is adjusted out much more than the other, the way mine came to me. I never put a protractor on it...the gaps told me enough.
 
#39
I definitely understand what you mean by the angled legs and the physics involved. I also understand why, if the adjusters were at an extreme position, that could make things unstable. For more normal conditions, it may be much ado about nothing to ponder the relative merits of nearly-perfectly-perpendicular or slightly angled legs. I suspect you'd agree that just because the style of bridge is such that the legs have a slight angle, that does not mean the legs will not fit the top properly. Here is a picture of my bridge as carved by the guys at Upton. I guess you'd call those slightly angled legs. In any case, the fit is rather pristine. It would have to be as I am a stickler when it comes to such details. :)


Img_1883.jpg
 
#40
Dear Drurb,

We clearly share a love of detail!

Thanks for posting the photo. If my bridge had looked like that, I would have never started down this road. With the adjusters so far "in", it looks quite stable. My adjusters came to me much farther "out" (even with a G string set at 5mm; E at 9mm).

Relevant background info/thoughts:
- I bought my bass used, as a consignment instrument. The bridge had been previously shaped much flatter, for the original owner, for primarily pizz-only playing. As an arco player, I needed a more traditional setup, suitable for pizz or bow.

- On the first reshaping attempt, instead of replacing the bridge, they recut the curve, moving out the adjusters a bit more. Unfortunately, the string spacings were off 1/8" from string to string, so this needed correction.

- On the second attempt, they still kept the same bridge, now shaped for the third time. This time, though, the adjusters were both out much farther and out roughly 3/8" more on one side. Thus, the instability and foot gaps...

I never took "before" photos, so can't illustrate graphically. All's well that ends well, however. Michael's bridge works beautifully. :)
 

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