I'm making a new bridge for a 1927 "The Gibson" L-1, that had a terrible DIY bridge replacement done in the 80's. Not a classical, but a more elaborate design. since there is no plan to be had and they made them with like 4 different bridges between 1926 and 1928, I had to extrapolate it's dimensions from photos The bad repair left a clear outline to see which bridge design it was. If you look them up, it's the one with the swooped back and an extra string pin behind the others in the center. With all the braces I re-glued, I got the soundboard back close to flat, and when I glue on a new bridge plate (the original was mangled) and the bridge, It should be near flat again. I will also have to graft in some wood, because when the DIY job rear loaded bridge snapped off, it took a bunch of soundboard with it, and there's a significant hole there. Some time next week I will be playing some Robert Johnson grooves on it! Can't try it with anything else, it was his main axe!😛
You are correct. Nice observation! In the video I say to make the cut you mention at 4mm, the same as the saddle slot because it is already set at this depth. Also, becasue if you go too deep then you have to remove more material from the wings until the saw mark is removed. Over time I have been able to "dial" my tolerances in a bit closer to my final bridge thickness on the wings, so I go a bit deeper in the cut. You can always remove material but it is hard to put it back. Happy Building!
Thanks, very much Robert! So, that makes the highest point of the wings approximately 5 mm. if my arithmetic is correct. You've a great gift at simplifying complex procedures for us novices. Thanks much!
Probably because of tradition but also weight. A bunch of abalone or MOP inlay on bridge wings will add mass to the bridge. You do see ornate tie blocks on classical guitars.
Thanks, Glad you enjoyed the video. I have never figured out what the exact angle is. I just eye balled it when I made my first bridge and have been using that ever since.
All of my videos are listed and available for viewing via my website. www.obrienguitars.com/videos This one is video number 27 under the Luthier Tips du Jour menu.
Does the bottom of the saddle slot end up flat after being cut with the table saw blade? Or do you need to run a thin chisel through there? Thanks for your videos by the way they really help.
+Graham Steward It depends on your sawblade and the grind of the teeth. Mine cuts a flat slot but if yours doesn't you can very easily use a file or even a stick with sandpaper glued to it to make the slot flat.
Yes, I radius the bottom of the bridge on both my steel string and classical guitars. I feel it is important to have a tight fit between the bridge and soundboard.
I'm interested in your claim that ebony "inhibits" tone and as to whether the claim pertains to its use elsewhere on the instrument - such as back and sides (and presumably you wouldn't extend such a claim to the fingerboard). I know the subject is too broad for this comment section but any reference or direction to a well sourced discussion would be greatly appreciated. Thank you.
Ebony is much stiffer, and therefore doesn't transfer as much vibration to the soundboard. With steel strings Ebony isn't much of a problem, but with nylon strings you want something more flexible, because they have less energy. Its also why they keep the wings thinner. As for "Tone" and especially "Tonewood" which is mostly BS as species is not a unit of measure, and it's a woods (any material) physical properties that counts, which can be compensated for to steer the final tone in construction method. Sides and backs make far less of a difference than what guitar snobs would have you believe, and it is also not at all science based, and can easily be debunked! The nut, fingerboard, ad neck wood also have jack all to do with the tone, but do matter in how stable they are, and stay over time. A neck that vibrates is often thought to be desirable, but the opposite is true! There is no such thing as perpetual motion, and the laws of thermodynamics apply to guitars just like everything else! A stiff neck that doesn't vibrate much is way better, as there is little string energy lost to it, and that means more for the soundboard. "Well vibrating" necks take away sustain, which most players want to have, not lose. Another false analogy: Maple necks are brighter: No they are not, they just absorb more bass, whereas Mahogany isn't "Darker" it just absorbs more treble, so you are not hearing more of one thing but less of another. On that note: Les Paul necks are not more stable because they are made of Mahogany, but because they are shorter in scale, and physically by some 4 inches, with a large portion of the fingerboard on the very stable body! In the end, if you study mechanical wave theory and some material sciences, you can easily spot all of the misinformation relentlessly perpetuated by even some of the best luthiers out there. Not that it prevents them from making great instruments, as in reality, Tone is subjective, and it's harder to make a bad sounding guitar than it is to make a good sounding one, and so there's plenty of room for doing it more free form and whimsical. So never be afraid to dare break the mold, and don't drink the Koolaid!
@@Bob-of-Zoid Thanks for the reply. I agree with the bulk of it. However this assertion of yours doesn't convince : "Ebony is much stiffer, and therefore doesn't transfer as much vibration to the soundboard." I would presume the opposite is the case. Rigidity transfers the greatest amount of energy (i.e. vibration). Instead of stiffness, the limiting parameter is mass (and associated inertia). I imagine that an infinitely stiff bridge of zero mass would be the ideal (perfect) interface between the vibrating string and the soundboard. I assume trial and error has lead to adoption of rosewoods as an ideal compromise between mass and stiffness. I'm unsure how maximum power transfer principles of impedance matching (from electrical theory) can be or are applied to this mechanical system. In particular I'm not familiar how the impedance of the boundary conditions between strings and soundboard (the bridge) are treated in any analysis that is made along those lines. However I own a classical guitar with a Macassar ebony bridge which performs very well, that species being slightly less dense than Gabon ebony and similar in stiffness. I think the observation made by many on brightness of necks etc is to an extent one of semantics. By saying a certain species is lighter or darker the judgement is on the perception of the final aural result podst construction, not pronouncing on an inherent property of the timber.
@@rjlchristie You are using vibration in a general term, but when it comes to material properties, frequency plays a big role, especially in musical instruments, and why when we talk of "Tuning a soundboard", we are not trying to get a good natural resonant frequency of a specific note, but to avoid them at all cost. Why? Because if you have a strung instrument and an area of a soundboard that resonates a fundamental note of the scale or higher it will resonate that note more than others and throw the overall volume out of balance. In two necks of equal dimensions one of maple responds to lower frequencies on average than the mahogany one, it's the response to differing frequency that comes at a subtraction of energy from the strings, therefor the soundboard, and all in relationship to power. So you have an ebony bridge on your classical, Robbie said you don't use ebony, or you shouldn't, and I said you can go about guitar building rather free form, and so if whoever designed the instrument decided on ebony, it may have been for looks as Macasar ebony can be stunning, or because they wanted a bit more treble response. It is also closer to most rosewoods, than black/white ebony. There's even a chance they were low on rosewood and weren't going to slow down production over it. Not two days ago I did work on a Cordoba classical with white ebony back, sides and headstock cap. Man was that thing sexy! For centuries it has been left to rot in forests after falling for being undesirable, and that only in looks, because in properties its no different than the black stuff, and comes from the very same seed, the coloration is due to something, but I don't know what it is. I do know I want to use it for fingerboards. I have some but only small billets (Pen turning blanks) I use for inlay. In mechanical energy the speed of propagation isn't a constant but related to density. Frequency is not related to the speed of the wave, light travels at the same speed no matter what frequency, and sound waves at the speed the elastic media can transfer it. The frequency is the distribution of the energy in time. Not to say you are one to believe that speed and frequency are one and the same thing, but many do: 5G conspiracy theorists and Crystal energy guru freaks, who if they were correct would vaporize in 3 seconds flat for stepping into direct sunlight!😜 No, you cannot apply the principle of impedance matching to mechanical energy, at least not with the same factors and ratio, nor does mechanical energy rely on quantum fields. There are considerations that could be loosely said to adhere to similar principles and analogues, but we know those already, they have names, and the relations are not quite the same. That being said, you must not only consider relationships, but their quantities, and of course the power levels in, and what you get out, and the differences between rosewood and ebony are not that far apart. There are differences within a species, even a tree depending on all sorts like the mineral content of the soil, weather conditions, and stresses on the trunk where you will have denser regions under branches or up one side of a trunk if growing on an incline... Ash for one is all over the place, and can be dense and heavy or less dense and light, yet nearly equal in stiffness. Mahogany also can vary pretty wide, but maple is pretty consistent. On that note carbon fiber is very dense, but also very light, and a great material for guitar building. I have been using carbon fiber rods in necks since the 80's, but it makes for great soundboards too, but it's one of those "Don't do this at home" things, and you need very expensive equipment like a big autoclave and lots of space to mold it and make parts. If you get a chance to play a Louis and Clark, take it.🤯
@@Bob-of-Zoid Frequency is simply a measure of rate of vibration. I used vibration in parenthesis to identify it as a manifestation of the energy in the mechanical system i was referencing. One needs to assume some basic mutual understandings without spending ages on defining definitions. " Frequency is not related to the speed of the wave," Umm,... Speed of a wave = frequency x wavelength. I suppose if you get into nuances of special relativity that identity might change, I dunno. Have you any references to further back up your claim in regard to impedance as I've heard the subject raised by makers quite frequently, in reference to compliance (i.e. impedance and admittance) matching of materials and structures. Yes, agreed that woods and individual trees all vary and discussion must be generalised. O'Brian makes the general claim that ebony is not a good choice for the bridge. Not saying it's untrue but I haven't yet heard any convincing rationale.
Is it me, or does it look like the cut to remove material in front of the tieblock to be about 6 mm? At 4:02, the cut looks both deeper than 4 mm and wider than 2mm. Or is this an optical illusion?
I'm making a new bridge for a 1927 "The Gibson" L-1, that had a terrible DIY bridge replacement done in the 80's. Not a classical, but a more elaborate design. since there is no plan to be had and they made them with like 4 different bridges between 1926 and 1928, I had to extrapolate it's dimensions from photos The bad repair left a clear outline to see which bridge design it was. If you look them up, it's the one with the swooped back and an extra string pin behind the others in the center. With all the braces I re-glued, I got the soundboard back close to flat, and when I glue on a new bridge plate (the original was mangled) and the bridge, It should be near flat again. I will also have to graft in some wood, because when the DIY job rear loaded bridge snapped off, it took a bunch of soundboard with it, and there's a significant hole there.
Some time next week I will be playing some Robert Johnson grooves on it! Can't try it with anything else, it was his main axe!😛
That white strip (bone or whatever) on the back of the bridge is a great idea... strings always bite into that part of the bridge.
You are correct. Nice observation! In the video I say to make the cut you mention at 4mm, the same as the saddle slot because it is already set at this depth. Also, becasue if you go too deep then you have to remove more material from the wings until the saw mark is removed. Over time I have been able to "dial" my tolerances in a bit closer to my final bridge thickness on the wings, so I go a bit deeper in the cut. You can always remove material but it is hard to put it back.
Happy Building!
perfeito! explicacao facil e sem firulas.
Obrigado!
Thanks, very much Robert! So, that makes the highest point of the wings approximately 5 mm. if my arithmetic is correct. You've a great gift at simplifying complex procedures for us novices. Thanks much!
Probably because of tradition but also weight. A bunch of abalone or MOP inlay on bridge wings will add mass to the bridge. You do see ornate tie blocks on classical guitars.
Ebono é prejudicial para os agudos. Por isso raramente vai ver isso num violão classico.
@kmh196700 If you are sure it is not the frets then check the nut and saddle break angles.
Great video thank you. What is the angle on your drill fence for your string holes?
Thanks, Glad you enjoyed the video. I have never figured out what the exact angle is. I just eye balled it when I made my first bridge and have been using that ever since.
@@OBrienGuitars, Thank you for getting back to me, and thanks for sharing your techniques, it is very helpful.
@themurkar Try reading up on what Somogyi has tyo say about it. That should help.
thank you
Hi Robbie,
So the bass side of the fretboard slopes down and the bridge on the bass side is higher? Why?
I thik it makes the saddle look better. There is less of a wedge shape in the saddle this way.
why isn't it listed your web site in the "About" or description or your video? Thanks for this video.
All of my videos are listed and available for viewing via my website. www.obrienguitars.com/videos
This one is video number 27 under the Luthier Tips du Jour menu.
Thank you.
Does the bottom of the saddle slot end up flat after being cut with the table saw blade? Or do you need to run a thin chisel through there? Thanks for your videos by the way they really help.
+Graham Steward It depends on your sawblade and the grind of the teeth. Mine cuts a flat slot but if yours doesn't you can very easily use a file or even a stick with sandpaper glued to it to make the slot flat.
+OBrienGuitars Thanks!
I have a Hirade Model 30 with a top crack right next and parallel to a brace. It creates a buzz and is dangerously flexible. How to fix?
Do you radius the bottom of the bridge to fit the contour of the sound board? Any advice concerning doing that or not doing that? Thank you.
Yes, I radius the bottom of the bridge on both my steel string and classical guitars. I feel it is important to have a tight fit between the bridge and soundboard.
Can i use walnut for the bridge?
Yes, you can. Some prominent luthiers are using walnut for bridge material.
What do you think about the String tie stuff?
Are you referring to the tie block bones?
@@OBrienGuitars yes. They really work well but Im not sure if it is good for the bridge because they change the pressure spot
@@viarnay I have never had an issue.
I'm interested in your claim that ebony "inhibits" tone and as to whether the claim pertains to its use elsewhere on the instrument - such as back and sides (and presumably you wouldn't extend such a claim to the fingerboard).
I know the subject is too broad for this comment section but any reference or direction to a well sourced discussion would be greatly appreciated. Thank you.
Ebony is much stiffer, and therefore doesn't transfer as much vibration to the soundboard. With steel strings Ebony isn't much of a problem, but with nylon strings you want something more flexible, because they have less energy. Its also why they keep the wings thinner.
As for "Tone" and especially "Tonewood" which is mostly BS as species is not a unit of measure, and it's a woods (any material) physical properties that counts, which can be compensated for to steer the final tone in construction method. Sides and backs make far less of a difference than what guitar snobs would have you believe, and it is also not at all science based, and can easily be debunked! The nut, fingerboard, ad neck wood also have jack all to do with the tone, but do matter in how stable they are, and stay over time. A neck that vibrates is often thought to be desirable, but the opposite is true! There is no such thing as perpetual motion, and the laws of thermodynamics apply to guitars just like everything else! A stiff neck that doesn't vibrate much is way better, as there is little string energy lost to it, and that means more for the soundboard. "Well vibrating" necks take away sustain, which most players want to have, not lose.
Another false analogy: Maple necks are brighter: No they are not, they just absorb more bass, whereas Mahogany isn't "Darker" it just absorbs more treble, so you are not hearing more of one thing but less of another. On that note: Les Paul necks are not more stable because they are made of Mahogany, but because they are shorter in scale, and physically by some 4 inches, with a large portion of the fingerboard on the very stable body!
In the end, if you study mechanical wave theory and some material sciences, you can easily spot all of the misinformation relentlessly perpetuated by even some of the best luthiers out there. Not that it prevents them from making great instruments, as in reality, Tone is subjective, and it's harder to make a bad sounding guitar than it is to make a good sounding one, and so there's plenty of room for doing it more free form and whimsical. So never be afraid to dare break the mold, and don't drink the Koolaid!
@@Bob-of-Zoid Thanks for the reply.
I agree with the bulk of it.
However this assertion of yours doesn't convince :
"Ebony is much stiffer, and therefore doesn't transfer as much vibration to the soundboard."
I would presume the opposite is the case. Rigidity transfers the greatest amount of energy (i.e. vibration). Instead of stiffness, the limiting parameter is mass (and associated inertia).
I imagine that an infinitely stiff bridge of zero mass would be the ideal (perfect) interface between the vibrating string and the soundboard.
I assume trial and error has lead to adoption of rosewoods as an ideal compromise between mass and stiffness.
I'm unsure how maximum power transfer principles of impedance matching (from electrical theory) can be or are applied to this mechanical system. In particular I'm not familiar how the impedance of the boundary conditions between strings and soundboard (the bridge) are treated in any analysis that is made along those lines.
However I own a classical guitar with a Macassar ebony bridge which performs very well, that species being slightly less dense than Gabon ebony and similar in stiffness.
I think the observation made by many on brightness of necks etc is to an extent one of semantics. By saying a certain species is lighter or darker the judgement is on the perception of the final aural result podst construction, not pronouncing on an inherent property of the timber.
@@rjlchristie You are using vibration in a general term, but when it comes to material properties, frequency plays a big role, especially in musical instruments, and why when we talk of "Tuning a soundboard", we are not trying to get a good natural resonant frequency of a specific note, but to avoid them at all cost. Why? Because if you have a strung instrument and an area of a soundboard that resonates a fundamental note of the scale or higher it will resonate that note more than others and throw the overall volume out of balance. In two necks of equal dimensions one of maple responds to lower frequencies on average than the mahogany one, it's the response to differing frequency that comes at a subtraction of energy from the strings, therefor the soundboard, and all in relationship to power.
So you have an ebony bridge on your classical, Robbie said you don't use ebony, or you shouldn't, and I said you can go about guitar building rather free form, and so if whoever designed the instrument decided on ebony, it may have been for looks as Macasar ebony can be stunning, or because they wanted a bit more treble response. It is also closer to most rosewoods, than black/white ebony. There's even a chance they were low on rosewood and weren't going to slow down production over it. Not two days ago I did work on a Cordoba classical with white ebony back, sides and headstock cap. Man was that thing sexy! For centuries it has been left to rot in forests after falling for being undesirable, and that only in looks, because in properties its no different than the black stuff, and comes from the very same seed, the coloration is due to something, but I don't know what it is. I do know I want to use it for fingerboards. I have some but only small billets (Pen turning blanks) I use for inlay.
In mechanical energy the speed of propagation isn't a constant but related to density. Frequency is not related to the speed of the wave, light travels at the same speed no matter what frequency, and sound waves at the speed the elastic media can transfer it. The frequency is the distribution of the energy in time. Not to say you are one to believe that speed and frequency are one and the same thing, but many do: 5G conspiracy theorists and Crystal energy guru freaks, who if they were correct would vaporize in 3 seconds flat for stepping into direct sunlight!😜
No, you cannot apply the principle of impedance matching to mechanical energy, at least not with the same factors and ratio, nor does mechanical energy rely on quantum fields. There are considerations that could be loosely said to adhere to similar principles and analogues, but we know those already, they have names, and the relations are not quite the same. That being said, you must not only consider relationships, but their quantities, and of course the power levels in, and what you get out, and the differences between rosewood and ebony are not that far apart. There are differences within a species, even a tree depending on all sorts like the mineral content of the soil, weather conditions, and stresses on the trunk where you will have denser regions under branches or up one side of a trunk if growing on an incline... Ash for one is all over the place, and can be dense and heavy or less dense and light, yet nearly equal in stiffness. Mahogany also can vary pretty wide, but maple is pretty consistent. On that note carbon fiber is very dense, but also very light, and a great material for guitar building. I have been using carbon fiber rods in necks since the 80's, but it makes for great soundboards too, but it's one of those "Don't do this at home" things, and you need very expensive equipment like a big autoclave and lots of space to mold it and make parts. If you get a chance to play a Louis and Clark, take it.🤯
@@Bob-of-Zoid Frequency is simply a measure of rate of vibration. I used vibration in parenthesis to identify it as a manifestation of the energy in the mechanical system i was referencing. One needs to assume some basic mutual understandings without spending ages on defining definitions.
" Frequency is not related to the speed of the wave,"
Umm,... Speed of a wave = frequency x wavelength.
I suppose if you get into nuances of special relativity that identity might change, I dunno.
Have you any references to further back up your claim in regard to impedance as I've heard the subject raised by makers quite frequently, in reference to compliance (i.e. impedance and admittance) matching of materials and structures.
Yes, agreed that woods and individual trees all vary and discussion must be generalised.
O'Brian makes the general claim that ebony is not a good choice for the bridge. Not saying it's untrue but I haven't yet heard any convincing rationale.
@kspianos Check out my video called Murphy's law. That might give you some ideas on how to fix the crack. Good luck!
how important is the actual weight of the bridge blank?
Very, Let's just say you can change things drastically with the mass of the bridge.
Is there anywhere to buy a pre made rough cut bridge?
Yes, try www.lmii.com
Is it me, or does it look like the cut to remove material in front of the tieblock to be about 6 mm? At 4:02, the cut looks both deeper than 4 mm and wider than 2mm. Or is this an optical illusion?