Replies to This Discussion

Permalink Reply by The Phrygian Kid on May 11, 2011 at 8:45pm

yep, yep,yep

 

neck angle + bridge height = volume + tone

 

do it

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Permalink Reply by Outhouse Instruments on May 12, 2011 at 12:19am

But it just ain't that simple. It's mostly for the higher pitched strings. You see a great angle on banjos, and mandolins ... anything with any type of bass or lower toned strings you won't see that big an angle.

It also depends on soundboard material & bridge location.

AFKAM

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Permalink Reply by The Phrygian Kid on May 12, 2011 at 3:22am

Matt WTF????

 

except cellos,  upright basses.....

just the olde world instruments that have not evolved in 300 years cos they are considered to be mastered by the Cremona masters in the 17th century...

 

In fact instruments that are designed for volume have a big tall bridge ( and a angled neck to allow this).  Witness jazz guitars too.

 

+ of course theres other factors including materials and design, no argument there

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Permalink Reply by Josh Gayou (SmokehouseGuitars) on May 12, 2011 at 6:06pm

Matt/Jeff - You guys are talking about full sized traditional instruments versus an 8" x 10" (on average) pressboard box.  You probably both have your points (in fact I know you do ;) ) but has anyone actually tried different variations of bridge height to neck angle on a cigar box platform?  I bet with a little experimenting in the shop (by Mungo as well) this could be answered definitively.

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Permalink Reply by Mark Werner on May 13, 2011 at 7:46am

Remember, more pressure from that taller bridge means you may have to add bracing as well.   I found this out with one of my builds; the 1/8" ply top started to collapse.

On the mandola I use as my sig, I used a 5 degree neck angle which is pretty much standard for this type of instrument.  The bridge ended up being about what you'd expect, and the near 1/4" solid-cedar top seems to be holding up just fine, though I did add an "X" brace.

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Permalink Reply by The Phrygian Kid on May 13, 2011 at 12:08pm

mark this is true and a good point

 

Josh, yes but do you not agree that just because we are jammin a stick into something that was originally packaging for something else does not mean we ought just ignore the science and engineering learned from the last couple centuries of luthiery?  I have conducted exactly the experiments you're talking about, but on cookie tins, and I'm quite convinced of what I'm saying. ( I did not keep any readings or data cos I wasn't out to prove anything for anybody else)  fella called Sanddraggin made an extreme neck angled CBG following discussions about exactly this over at the other forum, and he was in complete agreement with me too.   

 

this is Sanddraggins experimental build, he claims to be very familiar with this exact type of box, and so he felt the experiment was quite successful.

I will be very interested in anybody else's findings in this matter, as far as I know Sand and I are the only people who have actually conducted experiments into it

 

Ive been a big proponent for neck angles and tall bridges anytime anyone asks about em, I honestly feel that angling my necks and tapering em was when I really started to be happy about my own builds.  There have been one or two where Ive overdone it on the angle a little, particularly a neck thru solid body Im doing right now, the bridge is gonna be quite tall, but overall I'd much rather have too much angle than too little, and the action on my necks is much much nicer and more consistent across the whole length than i think could be possible on a zero degree plane..

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Permalink Reply by Josh Gayou (SmokehouseGuitars) on May 13, 2011 at 12:41pm

Not saying that we ignore it.  Just saying that a box format is so fundamentally different from anything that's been well documented in the past that you really have to experiment.

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Permalink Reply by Mungo Park on May 13, 2011 at 1:21pm

With the present build I have a box with a thin lid, about the thinnest I could find. I don't think I will produce a angle that will crush/damage the lid. I think their is some merit in trying some testing. I will measure the lid thickness and try out a few bridge hights. It will be hard to translate this to diferent lid thicknesses but could be a start. This sort of thing seems to have been worked out with other instruments, maybe some sort of ratio could be found such as for every mm of lid thickness the bridge is best at X mm high. Thanks all for your thoughts.

                                        Cheers Ron.

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Permalink Reply by hotlink larry on August 4, 2011 at 6:12am

I just finished my first CBG slider. No angle on the headstock, because i don't  have a table saw. It has a thru neck with a couple of inches of neck  protruding out the tail. I drilled the thru holes for the string-anchors there, in a place that just "looked about right", but  it sets the strings at a particular angle which puts front-to-back pressure on the eye-bolt I'm using as a bridge. This prevents me from locating the bridge exactly where I want it.. My intention was to set the bridge so that the 12th fret exactly is between the bridge and nut, but the pressure angle of the strings keeps pushing the bridge back toward the soundhole. Since it's a fretless guitar, I can  kind of compensate for any slight intonation issues, but I'd like to figure this out for my next project.

 

Any help or comments greatly appreciated.

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Permalink Reply by Bluesheart on August 6, 2011 at 5:53pm

You might use a couple of small screws or pins to keep the bridge bolt from creeping. Any kind of little stop would help. Even if you don't fret but you add markers you would need the bridge to stay put.

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Permalink Reply by Order99 on August 6, 2011 at 7:43pm

  Most instruments  i've seen with a high bridge often routinely either add a reinforcing wood plate under the bridge (guitar class) or a base bar/melody bar combo (violin class). Haven't gotten to examine a banjo yet-perhaps the skin used is tough and elastic enough, or maybe there's something under that hide...no idea.

 

 My first successful build (very recent too) was a two-box Cello with a decently high bridge-rather than angling the neck, I used a variation of the Uncle Crow guitar  build. I placed a full reinforcing bar under the lid top to bottom, added the neck straight across, bolting through the lid, then a tailpiece  bolted through and the bridge inserted directly into the tail. Inside where the boxes join I placed a vertical bar from the reinforcing bar to the lid as a built in Melody post. Action is almost straight across as a dulcimer would be. I'm not happy with my other design choices (I made the neck long and the post on the base too short leaving me either hunched over like Quasimodo or bracing in a chair) but i'm happy with the sound and there's no hint of give on the soundboard so far at full tension...

 

  I'll probably play with an angled neck when I actually know what i'm doing...but when I do i'm having some kind of reinforcement under the bridge.

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Permalink Reply by Chuck Dubman on August 6, 2011 at 8:34pm

Waverly style banjo tailpieces use a screw and lever design to press the strings down behind the bridge, increasing the volume by increasing break angle and downward pressure.  You could do the same with a hinge CBG tailpiece by installing a thumbscrew in the center of the top plate.  Banjo bridge height right out of the box ranges from 3/8" to 5/8".  3/4" wouldn't be unheard of in a one-of-a-kind handmade instrument.  If you can play it, it's not too high.

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