Tone bar variations

[Antlurz]

Back in the fog of my alleged brain, I've entertained the thought of, when carving a top, to carve the bracing out of the one piece of the top itself instead of gluing them in.

Not sure what benefits/problems doing so might reveal, but still, it peeks the curiousity. At least it does with me.

Anyone else ever consider doing this?

Ron

[craigtoo]

well.. on violins it's been done for years... but is sometimes considered to be a trait of the "cheaper" instruments....

craig

[van]

I have thought about that too Ron but I havent tried it because it seemed like a lot of tedious work. I don't think that it would make an instrument cheap, if anything it should be worth more for the extra work involved. As far as quality and sound goes, I don't think that it would be much different than the traditional method but I can see myself trying it one day, atleast once.

[Jim Rowland]

Integral tone bars actually avoid one of the most tedious and uncertain tonebar problems in that you do not have to fit the bars perfectly to the undulating top. In addition,consider the fact that bars run at an angle to the grain of the plate,so integral bars present something akin to runout from neck to tail. A really good,careful job of it probably doesn't have a huge effect,but luthiers striving to squeeze the last scintilla of tone and volume out of the wood have been avoiding integrally carved bars for a long time. Actually,I've never tried it,so I don't know for sure.
Jim

[woodwiz]

The only fiddles I have seen that done on were screechboxes that didn't even have corner blocks. Definitely low end.

[sunburst]

I'm well aware that integral bass bars only tend to show up in cheap fiddles, but I can't think of any reason that they couldn't work well if done well. The question, to me, is; would they be any better than glued in bars, and if they are not better, why bother? Glued in bars work fine.

In these days of CNC carving, the amount of work would be reduced a lot. It would probably be less work than glueing in tone bars.

I, for one, probably won't try it. I don't CNC carve (yet), and graduating a top with tone bars sticking out of it doesn't sound like much fun to me. Also, I like to be able to judge the stiffness and other properties of a top before and after installing the tone bars.

[Antlurz]

The runout situation concerns me a bit, and all of the things Sunburst mentioned were things I had thought about as well. As you mentioned, that would be a lot of extra work unless one created the Holy Grail of Mandolins by doing so. My concern with runout would be the possibility of a fracture along one of the lines, but after considering it further, I doubt a top flexes enough in a short enough distance to fracture one unless it was a flaw in the wood to begin with. I might be tempted to do it once just to see what the results were, but in truth, if I didn't perceive a sizeable postive result, doing it the second time would hardly make sense.

Still, if it has ever been done, my curiousity would love to hear about the results. A sizeable part of my life has always revolved around "what if's" http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Ron

[Michael Lewis]

Carving the inside of the top would be much more difficult if you had to carve around the tone bars.

IF you are using CNC, and IF you are using nearly straight tone bars it could save the work of gluing in fitted bars. But if you have CNC you could cut the bars to fit and glue perfectly and not have to labor to fit them. Otherwise, if you are doing this by hand you would be making more work and most probably have an inferior instrument. I could be wrong but I don't think so. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif

[thistle3585]

It would be pretty difficult to do on a CNC anyhow. The curvature of the top would prevent you from being able to cut the bar square, so you would have to stop short of the tone bar. That would leave you quite a bit to hand chisel out. You may also get into some tearout issues if the tone bars, as well as the grain, are not parallel to the cutting path. Maybe if you had two cutting heads then you could do it as a secondary operation.

[banjo1]

I have only repaired instruments and have never built but it looks to me that most tone bars have much more grian line than does the top wood. As well as transmitting the sound better, would it not add a little strength to top as well?

[Michael Lewis]

Higher count grain lines in wood does not automtically mean it is stiffer or stronger or transmits vibrations better than wider spaced grain lines. You have to test each piece for structural qualities, then proceed as your experience directs.

[banjo1]

Speeking of this thing called experience, Michael..............how long have you been building?
I have loved every answer that you have came back with.

[Michael Lewis]

Adam, I started my business in 1981 when my wife was still holding down a good paying job. Really started to focus on mandolins about 1984 or '85.

[Rob Grant]

Carving tone bars integral with the top would be waste of time. If you were using "X bracing" your grain direction would be very weak, inconsistent and variable along the structural line of the brace. Properly graduating a top without bracing and getting a good tone is hard enough!

[Antlurz]

Construction complexities notwithstanding, Michael Lewis mentioned CNC earlier and it got me to slide onto another tangent. "C" shaped tone bars. Hot bent and spanning the dimensions between cross bracing and the normal tone bars.

I need a drink. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif

http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Ron

(Yeah, I know. Useless meanderings.....)

[Michael Lewis]

OK Antlurz, give it a try and report back to us. If you really like the results you can patent the design. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wink.gif

[John Bertotti]

I remember a couple years ago someone was using and trying to patent some kind of curved tone bar as mentioned above. I'm not sure how far that went or who it was.