Fingerboard wedge instead of correcting neck angle

[Fiddler45]

I make a wedged fingerboard and cut the underside to make the free end thinner.

 

I've seen a few separate wedges with glue joints that have failed, and they can be a curse to fix if both joints are loose and if they're thin.

I do this also when the angle isn't off by too much, and where it won't make the board too thick. I also did the reverse on my wife's fiddle, because the bridge that was on it was too high, and it couldn't come down much at all due to a slightly steep neck angle. I reversed the wedge shape on the underside of the board, and it plays and sounds worlds better than it did before.

[JSully]

 

Off-topic, but still relevant, when giving a quote on repair work, does one take in account the value of the instrument? For example, you cannot really charge 300$ for a repair on a 50$ violin. Unless ofcourse, you had to buy spesific items nececary to do the repair.

 

I'm sure this has been answered already, but why not?  The value of a luthier's time doesn't change depending on the instrument in front of them.

 

I've paid a repair bill that was probably higher than the instrument's worth.  But it had sentimental value, and I had plans for it.  I wrote the check, the luthier took the check, and everybody was happy.

[Peter K-G]

Jakob,

You sound somewhat upset by my post. We might not have such different opinion as you put it, only different viewpoint on the subject!

My violins has an average bridge height of 31,5 mm and string angles over the bridge between 158-163 depending on which string I look at, as I use harp shaped tail pieces. (http://www.maestronet.com/forum/index.php?showtopic=328812)

This topic is about a violin that probably has the neck angle wrong. My point is that the angles should be equal (ex. 79/79) on both sides, otherwise the bridge has more tendency to bend in either directions. And as you pointed out due to tuning. If I make (non)sense or not, it can be tested, I have

No need to fight over this, I'm only trying to help

Peter

[Jacob]

Hi Peter,

 

Sorry if I came on too strong. I'll try to be more neutral. The two points on which I differ strongly:

 

1. Splitting the string angle evenly over the bridge. I can't even imagine how this could be possible;

2. That the angle, or one part of it, determines in which direction a bridge tends to bend.

 

I've never heard these theories before, and have not encountered them in practice before.

 

I'd very much like to know how you attain the evenly-split angle. Somewhere along the line you must be using settings which are way off the chart - either an impossibly high saddle, or an impossibly steep neck/fingerboard angle. The only other possibility I can think of is that your bridges lean backwards to quite some extent. That's not standard practice either.

[dan_s]

I remember that, some years ago, there was a strong advocate of equally  split angles on MN....If I could just remember who that one was...............

[Jacob]

You obviously remember as well as I do (I was wondering behind which bush you've been hiding).

 

Live and learn.

[Peter K-G]

Hi Peter,

 

Sorry if I came on too strong. I'll try to be more neutral. The two points on which I differ strongly:

 

1. Splitting the string angle evenly over the bridge. I can't even imagine how this could be possible;

2. That the angle, or one part of it, determines in which direction a bridge tends to bend.

 

I've never heard these theories before, and have not encountered them in practice before.

 

I'd very much like to know how you attain the evenly-split angle. Somewhere along the line you must be using settings which are way off the chart - either an impossibly high saddle, or an impossibly steep neck/fingerboard angle. The only other possibility I can think of is that your bridges lean backwards to quite some extent. That's not standard practice either.

 

Great!

 

Answers that I have to this is:

 

1. I think the backside of the bridge should be perpendicular to the top/ribs and that it is not that hard to adjust the sadle height to get the same angle on both sides of the bridge.

 

2. It's not a theory, this is based on my own experiments. I understand why too, but I would need to make an illustration I can't explain it in text.

 

Here is an example of the evenly split angles.

http://woodsoundstudio.com/setup.htm

 

Michael Darnton has also written about neck angle and 158 degrees over bridge.

[Peter K-G]

Here is an update with Titian and Plowden as examples. Both violins has bridges leaning forward which is not unusual (tuning, playing and front feets digging into the top)

 

* This is the root cause for the bending if the angle is to gentle in front of the bridge.

* The split (~79/79) should be examed together with the bridge's own angle.

* Titian can handle  ~158 (I think it's more like ~160) degrees string angle over the bridge. Plowden can not it's probably around 165.

 

 

[Jacob]

Hi Peter,

 

I'm trying to wrap my head around all this. I have a feeling that trigonometry will tell us something, but maths/trigonometry is probably the weakest of my many weak spots, so you may have to help me out here.

 

Let's do a body length of 356mm
a stop of 195mm
which leaves 161mm to the saddle (except that the saddle apex is/should be about 2.5mm in from the edge of the top, which makes the scenario even worse in terms of getting to the magical 79º)
an arching height of 16mm
a bridge height of 31.5mm, with the back of the bridge at right angles to the top (sort of, although not really - the top of the bridge should be more like 2/3 from the front of the foot, 1/3 from the back)
a saddle height of 7.5mm
all of these being standard measurements.

 

The tricky bit for me (without resorting to mathematical alchemy) is to get the back portion of the string angle at 79º (if it is splitting a 158º string angle over the bridge). Working with these measurements, the back portion of the angle I get is 76º. In order to get it to 79º, leaving the arching height, bridge height and stop length/body length the same, it seems to me that the saddle height would need to be 15.5mm - on a violin.

 

Where am I going wrong?

 

I'm assuming we are working with "real" numbers, not "it looks like". Even if we work according to "it looks like", the back portions of the two lovely images you posted clearly (at least to me) seem to be considerably tighter than the front portion.

 

As for the 160º+ angles you propose for the two instruments - that may or may not be the case, but one will never know, simply because violin strings are not designed to provide an adequate and reliable BOWED RESPONSE at that kind of angle (and lack of "upward pressure" from the bridge). Now, if those were guitars it would be a different story. We'd be plucking our way right past the guards at the Pearly Gates.

[Jacob]

PS - this is how I tried to calculate all this - perhaps somebody can tell me where I went wrong:

 

Height of the side of the triangle at the bridge: arching height 16mm + bridge height 31.5mm = 47.5mm - minus saddle height 7.5mm = 40mm. Length of stop to edge = 161mm. Angle between these two sides = 90º.

 

I'm absolutely sure Mr Pinkham, in the link you provided, has this all figured out. I'm into the "Live and Learn" thing, so any assistance with this will be appreciated. It would simply kill me to know I was right eight years ago and has retrogressed to getting it all wrong now.

[Peter K-G]

The only thing you might be missing is that the bridge is a wedge with about 3 degrees and that the tail piece extends past the violin.

 

For a violin with a low arch (14,5-15,5 mm), and a bridge of 31,5 mm,  the nut has to be under the imaginary line extended from the top/ribs joint, otherwise the angle over the bridge is more than 158 degrees. This you can exam by viewing along the side and visually extend the top/ribs joint to the nut.

 

There is allways a simple way, I bet Stradivari was no mathematician

[Jacob]

Peter,

 

I don't think you've understood and/or addressed my query. I'd very much like you to show me the numbers how to get to a back angle of 79º. Be as specific as you like, but not as vague as you've been so far. Your link to Pinkham shows measurements which I can only call "mathematical alchemy". I can take his diagram and pencil in any angle I like - which I what suspect is he did. It's easy to mix up ideals with reality - ask my buddy Dan'l. It really doesn't matter what degree of wedge the bridge has - it could be 30º if you like. The string angle refers to a specific measuring point, which is the apex of the bridge. It matters where this apex is in relation to the stop, and therefore from which point you calculate the triangle. But there has to be a point, and also a "point". Let's get down to business - show me the numbers.

[Jacob]

PS - Don't get confused. For now it's ALL about the back angle, which needs to max out at 79º to make your (and my old, and Pinkham's) theory work. This is what it all hinges on. You can make the front angle almost anything you want, but it's the back angle which is the fly in the soup, the water in the gasoline, whatever you want to call it.

 

Your bridge-leaning theory deserves a response: yes, with the tighter angle at the back there is forward pressure on the bridge, so theoretically there is a "tendency" for the bridge the bend forwards. In practice, since the strings DON'T slip over the bridge (thank goodness for that at least), the bridge will lean/bend in the direction to which it is pulled by tuning - either fine-tuners or pegs. That is why good bridge shaping involves leaving strength in the bridge to counteract this without leaving unwanted mass. For tonally optimal bridges I guess what is taught at places like the Mittenwald school can't be beat (I wouldn't know for sure) but they are as rickety as my arthritic knees. I have old bridges here from the Hills shop, Beare, and Sacconi. Those are my models.

[dan_s]

 I bet Stradivari was no mathematician

 

Don't know about that but I bet he wasn't stupid.

[Jacob]

Don't know about that but I bet he wasn't stupid.

 

Amen bro'.

 

There has been ample mention here of the "kitchen mathematics" of those days, the level of which is barely attainable by most these days. Possession of a divider may prevent one from getting onto an airplane these days, but then would have been a tool of first resort for all kinds of artisans.

[Jacob]

PS - Don't get confused. For now it's ALL about the back angle, which needs to max out at 79º to make your (and my old, and Pinkham's) theory work. This is what it all hinges on. You can make the front angle almost anything you want, but it's the back angle which is the fly in the soup, the water in the gasoline, whatever you want to call it.

 

Your bridge-leaning theory deserves a response: yes, with the tighter angle at the back there is forward pressure on the bridge, so theoretically there is a "tendency" for the bridge the bend forwards. In practice, since the strings DON'T slip over the bridge (thank goodness for that at least), the bridge will lean/bend in the direction to which it is pulled by tuning - either fine-tuners or pegs. That is why good bridge shaping involves leaving strength in the bridge to counteract this without leaving unwanted mass. For tonally optimal bridges I guess what is taught at places like the Mittenwald school can't be beat (I wouldn't know for sure) but they are as rickety as my arthritic knees. I have old bridges here from the Hills shop, Beare, and Sacconi. Those are my models.

 

And, especially when new strings are fitted (or a new tailpiece adjuster) the bridge inclination needs to be adjusted during stretching of the strings/tailpiece loop. If this were not absolutely necessary, without exception of any kind, we would all be able to levitate on demand.

[David Burgess]

Peter, take another look at your photos in post #33. These Strads were probably worked on by very good people. The bridges they made do not bisect the angle of the strings, yet the bridges to not appear to be warped. Maybe they know something that you don't?

 

If bridges had little rollers under the strings, yes, they would go kaboom if the string angle on both sides of the bridge was not the same. But there's enough friction between the strings and the grooves that this doesn't happen. Most of the reason the top of the bridge moves toward the scroll in use is because when strings stretch, and are brought back up to pitch, the slack is taken up on the scroll end of the string. The entire string moves in that direction, and brings the bridge along with it.

You can bisect the angle of the strings with the bridge, or even tilt it back further than that, and it won't make much difference. The bridge will still move forward.

 

If the tuning pegs were on the other end of the violin, the bridge would move in the opposite direction, toward the lower block.

 

You're doin' good, Jacob.

[Jacob]

If the tuning pegs were on the other end of the violin, the bridge would move toward the lower block.

 

 

Or, as I've mentioned, if the tuning mechanism of choice is fine-tuners on all strings, in which case the bridge does move towards the lower block. So, every new instrument I deliver comes with a printed set of maintenance instructions, as well as a 10-minute demonstration and practice session for the operator of the instrument (or parent/guardian) on how to steady the bridge, every now and again loosen the fine-tuners so that they don't hurt the foot soles of people on the opposite side of the globe and retune with the pegs (which also prevents the pegs and peg holes from freezing into place, needing something just short of a dynamite blast to release them, followed by peg-hole reaming to restore the shape from oval to round, and the fitting of new pegs).

 

I'm not ashamed to service the very bottom of the market. It is a worthy challenge, and if done with respect towards the instruments (whatever their merits) and the customers (who sometimes end up in the higher echelons of Western classical performance - or not) I don't really perceive any difference between that and doing the same while dealing mainly with classical Cremonese and their owners. The main difference might be that my customers are more demanding. On the other hand, I have mininum requirements also, and if my customers don't care enough, I'm not prepared to care at all - they can go somewhere else.

[Peter K-G]

Peter, take another look at your photos in post #33. These Strads were probably worked on by very good people. The bridges they made do not bisect the angle of the strings, yet the bridges to not appear to be warped. Maybe they know something that you don't?

 

If bridges had little rollers under the strings, yes, they would go kaboom if the string angle on both sides of the bridge was not the same. But there's enough friction between the strings and the grooves that this doesn't happen. Most of the reason the top of the bridge moves toward the scroll in use is because when strings stretch, and are brought back up to pitch, the slack is taken up on the scroll end of the string. The entire string moves in that direction, and brings the bridge along with it.

You can bisect the angle of the strings with the bridge, or even tilt it back further than that, and it won't make much difference. The bridge will still move forward.

 

If the tuning pegs were on the other end of the violin, the bridge would move in the opposite direction, toward the lower block.

 

You're doin' good, Jacob.

 

David & Jacob

 

I have no doubt, the people making the bridges on theese violins are obviously world class violin makers and they know a lot more than I do. I think Jacob is doing great too! As this illustration/calculation also shows. No matter how I bend the formulas and trying hard to get the exact angles, this is the best I can do:

 

 

ps.

Sometimes when you have too little to do, try to mess around with the neck angle - the bridge will bend towards the less steeper angel

[Melvin Goldsmith]

I'm not sure if what follows is on topic or not but might be of some interest to some folk. 

On my most recent visit to the current Stradivari exhibition at The Ashmolean in Oxford, UK, I happened to notice that the neck overstand on several of the very well preserved and relatively un molested but never the less modernized at some point violins was about 2-3 mm lower than what is now considered 'standard' set up. This is quite visible in the catalog also and not altogether uncommon.

[David Burgess]

 

Sometimes when you have too little to do, try to mess around with the neck angle - the bridge will bend towards the less steeper angel

Been there, done that, and it didn't happen.

If you want to experiment with angles some more, an easy way to change the string angle on the backside of the bridge (as well as the total string angle) is to clamp an old chinrest in the saddle position, and run the tail adjuster over the top.

[Brad Dorsey]

It's pretty easy to conduct a thought experiment that shows that unequal string angles over the bridge will tend to push the bridge towards the side with the larger angle:

 

Imagine a bridge where the string angle on one side is zero and on the other side 90 degrees.  In other words, the string goes up tight to one side of the bridge, and leaves the other side at a right angle to the bridge.  Obviously, any tension on the string will cause the bridge to fall over towards the side with the right angle.

 

Now I have described an extreme example.  The closer the angles are to equal the less net force there will be on the bridge towards one side of it.  To understand this, imagine two more extreme examples:  Imagine that the angle is zero degrees on both sides (i. e. the string goes up tight to one side of the bridge and goes down tight to the other side), or imagine that the angle is 90 degrees on both sides.  Obviously, in either situation what force the string exerts on the bridge pushes it straight down, and not to one side. 

 

The way a violin is usually strung, unlike in any of my extreme examples, the string angles on either side of the bridge are reasonably close, so the force pushing the bridge to one side is small.  It is small enough that the friction between the strings and the bridge is enough to overcome the force that is trying to tip the bridge.  But, as David pointed out, if you eliminate this friction by passing the strings over frictionless bearings on the top of the bridge, the bridge will fall if the angles are unequal.

 

Since the string tension on the bridge tends to tip the bridge towards the side with the largest string angle, I think that the bridge would tend to warp so that it is concave on that side if other things are equal -- other things like the fit of the bridge feet to the top of the instrument and the strength of the bridge wood. 

 

I fit my bridges with a right angle to the top on the tailpiece side.

[David Burgess]

Flawed thought experiment conclusion.  As long as the strings are fixed in the bridge grooves (as they essentially are on a real violin), there needn't be any fore/aft force on the top of the bridge, and the force vector running from the top of the bridge to the feet can still be a straight line through the center of the bridge, if so desired.

 

(edited twice, with this being the original version. Thought I got the original version wrong, so I changed it, but then realized that the original version was correct.)

[Brad Dorsey]

Flawed thought experiment conclusion.  As long as the strings are fixed in the bridge grooves (as they essentially are on a real violin), there needn't be any fore/aft force on the top of the bridge...

 

David,  I don't follow you.  I thought I had this all figured out.  Can you explain how my conclusion is flawed?  Faulty logic?  Flawed premises?

[Jacob]

 

 

I have no doubt, the people making the bridges on theese violins are obviously world class violin makers and they know a lot more than I do. I think Jacob is doing great too! As this illustration/calculation also shows. No matter how I bend the formulas and trying hard to get the exact angles, this is the best I can do:

 

BluntAngleCalc.jpg

 

 

Peter, those figures are fudged. Just two of the flaws: adding the thickness of the tailgut to your calculations, and including the bridge "wedge". Your illustration in fact shows a back angle of 76.6º. If the total string angle is 158º, that would make the front angle 81.4º. I'm not familiar with the branch of trigonometry which allows one to DIVIDE a triangle by making a portion of one leg disappear. That sounds like alchemy to me.