Bone as Bridge Material?

[ngerty]

I've read that the bridge is a very important component of the guitar because it is what drives the top and transmits the strings vibrations to the body. I've also read that ebony doesn't transmit vibrations nearly as well as other woods and other materials. So, why not fashion a bridge out of bone (or some other very hard, non-dampening material)?

Wouldn't a bone bridge do a much better job at transferring the energy from the strings into the top and body?

I don't know how I would procure a piece of bone suitable for a bridge, but in theory it would work very well, right? Maybe I could buy a bunch of saddle blanks, glue them together, and then shape the piece... Probably not.

For my first guitar though (D28 style kit) I'm considering widening the saddle slot to twice its normal size so I can have two saddles and more surface area for the strings to contact. In my mind this just makes that energy transfer more efficient. The second saddle would be installed on the side of the bridge pins and in turn the break angle of the string would be greater. More pressure then down on the top though. Too much? Maybe the added pressure down will counter the upward pull to a degree and slow the formation of the usual bulge behind the bridge?

Any thoughts?

[ngerty]

*I posted this in the Guitar Building Procedure section but though I'd post it here too so more people might see it...

I've read that the bridge is a very important component of the guitar because it is what drives the top and transmits the strings vibrations to the body. I've also read that ebony doesn't transmit vibrations nearly as well as other woods and other materials. So, why not fashion a bridge out of bone (or some other very hard, non-dampening material)?

Wouldn't a bone bridge do a much better job at transferring the energy from the strings into the top and body?

I don't know how I would procure a piece of bone suitable for a bridge, but in theory it would work very well, right? Maybe I could buy a bunch of saddle blanks, glue them together, and then shape the piece... Probably not.

For my first guitar though (D28 style kit) I'm considering widening the saddle slot to twice its normal size so I can have two saddles and more surface area for the strings to contact. In my mind this just makes that energy transfer more efficient. The second saddle would be installed on the side of the bridge pins and in turn the break angle of the string would be greater. More pressure then down on the top though. Too much? Maybe the added pressure down will counter the upward pull to a degree and slow the formation of the usual bulge behind the bridge?

Any thoughts?

[rgogo65]

Well. I'm no expert by any stretch and probably shouldn't even comment here, but even though I'm very lacking in acoustic building, I have had the pleasure of PLAYING many guitars over the years, including a couple of old Martins, as well as a few "Other" parlor type guitars with bridges that certainly qualify as being "Different" from the norm of today.
One of those impressive little guitars was a Martin with an ivory bridge.It also had ivory pins as well. This was NOT a steel stringed guitar. As I recall, the strings were a steel "Wrapped" silk combo and they produced a fantastic smooth mellow sound unlike anything I have ever heard.
Why? I THINK that could be argued forever. My personal feeling was it was a result of a combination of things. The bridge composition, the mounting method, the wood used, the construction of the bracing and the type and quality of string. The chain is no stronger than the weakest link and in no way is that more evident than with a guitar and it's sound.
I have experimented with different pins, and different saddle materials and the sound they produce. While I haven't changed many bridges, I discovered there is a lot of difference in saddle and pin material with any given guitar.
I have an early Guild that feeds off of a bone saddle and nut..nothing else works...period! I have another little flat top that just doesn't sound right with anything but tung. So go figure...
My point is, each guitar will have it's preference and it may be so with bridges...I THINK rosewoods have a particular sound I'm drawn to...but don't forget, the bridge plate and gluing method is a big part of the equation.
Wayne Henderson VERY particular about his bridge plates, their size and the selection of maple used. He won't use anything else...and he swears it has a great deal to do with the resulting sound.
I didn't mean to ramble, but I hope I shed some useful light on the subject from simple observation.
I'll leave it up to the experts here to say whether a bone bridge id a good idea or not...and I'm in no way recommending the use of ivory or any other material for that matter, but I do think, (My personal opinion) that
experimenting with different materials MAY produce some interesting results and it's something I would and will try.

[Freeman]

I also am not an expert, but have a few observations and opinions.

First, yes, there were a few guitars built back in the 20's that had ivory bridges - Martins, Washburns, maybe some others. I think it was done for appearance, but personally I think they are ugly (not to mention that I also am opposed to ivories but that is another story).

If you read lutherie forums you will see that bridge mass gets debated a lot - some argue for less, some for more. I do know from personal experience that replacing the thick heavy rosewood bridgeplate on my D18 made a dramatic difference in sound - my wife's comment when the work was done was "you are playing louder tonight". You will certainly be affecting mass - can't tell you if that is good or not.

Consider that some people argue that the action of a pinned (or as Roger Siminoff calls it "fixed") bridge is not to vibrate the top up and down, but to rock it around the center line of the bridge itself - think of the saddle as a telephone pole with a little guy wire (the section to the pin) and you'll see that it can't impart a direct vertical component. Instead, Siminoff says, the expansion and contraction of the strings tugs at the top of the saddle, pulling then releasing it, driving the area between the bridge and soundhole down and the lower bout up. If you buy that arguement (and I do having built both fixed and floating bridge instruments) then the main function of the bridge is simply to anchor the bottom of the saddle to the top and provide the fulcrum point. (A float bridge such as mandolin, violin, resonator, or tailpiece guitar does have a vertical component into the top at the saddle - totally different mechanics). If you want to avoid top rotation your second saddle won't do it - add a tailpiece and change the bracing.

Stop and think too, that to shape a bridge out of bone (or ivory) will be one hell of a lot of work - most commercial ones are cnc'ed and you will be doing a lot of work with a belt sander and router to try to duplicate it. You'll have to find a big enough hunk of bone at a butcher shop, clean and degrease it, then shape it, finally routing the saddle slot and drilling, reaming, slotting and ramping the pin holes.

You will also notice that the saddles on most guitars have a relatively sharp (but rounded) top edge, your wide saddle will defeat that. The wide saddles do have a very real use for compensation - if you have particularly difficult intonation issues you might consider a thicker saddle piece (I use them on my 12 strings so I can compensate each string of each course).

My humble advice (and it is well presented by Running Dog in the 12 vs 14 fret discussion) is not to screw with a design that has been developed over several centuries for your first build. Or for that matter your tenth. Until you can make good consistant guitars duplicating what people consider good sound, why screw it up with something that no body else uses.

[Freeman]

Ditto and see my comments on the other sub forum.

Since you have posted this in two locations you are going to get a very confusing discussion. Maybe the mods could condense this into one thread.

[Freeman]

Interesting comments by Allan Carruth in post #15 about break angle

http://theunofficialmartinguitarforum.y ... pic/105984

[ngerty]

I've seen pictures of those ivory-bridge Martins. I bet they sound nice. I'll stick with woods for know...

I wasn't aware of different saddle widths. A thicker saddle was all I was hoping to create. Will a thicker saddle create intonation problems on my guitar? If the extra width is added on the side of the saddle closest the bridge pins and is slightly sloped downward, I don't see why there would be any problem...

[Darryl Young]

I wasn't aware of different saddle widths. A thicker saddle was all I was hoping to create. Will a thicker saddle create intonation problems on my guitar? If the extra width is added on the side of the saddle closest the bridge pins and is slightly sloped downward, I don't see why there would be any problem...

Well, it will be wherever you cut the saddle slot.

In regards to Siminoff's opinion that most of the guitar's sound comes from the bridge rocking instead of vibrating the bridge up and down. I read his book and thought he made a decent case for this argument. I've discussed this with Al Carruth in a couple differnt posts on forums and he is convinced this isn't true and that it is the other way around. He says most of the power of the guitar comes from the monopole mode (where the soundboard vibrates in and out like a speaker) which is due to the strings bouncing the bridge up and down. He has done several tests to prove this to himself. After hearing Al's arguments, I tend to agree with him and not Siminoff.

[Freeman]

Ngerty, the standard saddle thickness for Martin style bridges is 3/32 -that usually works fine for compensating a normal string set. On my 12 strings I bump that up to 4/32 to give a little more meat in the bone (bad pun) - I compensate each string of each course (the saddle ends up looking a little bit like a rip saw blade). Obviously if you are making your own bridge (out of whatever material you choose) you can route any width slot you want - your only problem there will be sourcing bone blanks thick enough (you can get cow bone at any butcher shop or blanks from luthie supply houses).

When most of us make a saddle we make the break point fairly sharp, but rounded so it doesn't break the string there. You don't want a wide flat top on the saddle. There are different ways to find that break point - I use the little trick of putting a piece of wire (a B string) under each string while the top of the saddle is still flat and moving it back and forth until the intonation is a good as I can get it, mark it and then file the break point. You are a long ways from that point, but as you build you do need to be thinking about the final saddle location.

And yes, Darryl, I too have a great deal of respect for both Roger and Al (and many many others). I try to learn from each of them - but sometimes what they say is very contradictory. I had the pleasure of listening to seminars by Siminoff, Bourgois, and Michael Cone at the last GAL conference about tuning top plates - three very different approaches but all getting wonderful results.

I'll add that I have built both tailpiece instruments (mando, resonators, ladder braced guitars) as well as pinned bridges - from an engineering standpoint I think Roger's theories makes sense. However, computer models do seem to support Curruth's arguements....

(the more I learn the less I really know.....)

[tippie53]

On the UMGF thread , I had originally posted about the break angle . Alan and I have had a few discussions about these. The Break angle has very little to do with things than what was first thought of. The break angle doesn't take in consideration the overall distance of the pins to the top of the saddle.
On top of that you have the total influence of the plate , top , bridge , saddle , and pins. The correlation of all this had an influence. On thing that I notices is the cause effect of the total mass of this structure.