Thank you very much Mark, i'll be using some that i have, i think one of the pieces has the grain at 45 degrees so i should be good to go then!
Serge
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| grain orientation of a bridge? http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=6607 |
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| Author: | altec [ Tue May 09, 2006 8:03 pm ] |
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Hi everyone I’m aiming to make a good classical for myself before the end of the year, I’m still starting out hence a very noobie question =) : is a classical bridge better off flatsawn (the lines go from left to right when viewed on the endgrain; right?) or quarterswn (top to bottom ala soundboard albeit the lines go from lower to upper bout?) I got a board of langka (jackfruit) and ebony here that i could cut either way and it would be less than 10 degree off from perfect... Flatsawn looks better by far, but structural-wise it seems to me that it should be quartered…. Is this so? |
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| Author: | TonyKarol [ Tue May 09, 2006 10:59 pm ] |
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quartered or close to it is best. |
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| Author: | A Peebels [ Tue May 09, 2006 11:17 pm ] |
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I know that quartered is considered to be the best grain orientation for a bridge, But I think this may be wrong. It seems to me that quartered wood will have a tendancy to split frome one hole to the next because of the allignment of the narrow dimension, the string holes, and the grain. Flatsawn will have the grain 90 deg. to the narrow dimension, reducing the likelyhood of splitting. Al Peebels |
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| Author: | crazymanmichael [ Tue May 09, 2006 11:37 pm ] |
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i prefer my steel string bridge blamks to be at least 30 degrees off quarter, up to 45 degrees, and for the grain to be slanting diagonally across the blank from corner to corner. this greatly increases the resistance to splitting at the saddle slot and the pin holes. given the significantly lower tension in a classical i doubt that being off quarter would be of similar benefit and a quartered blank would be quite ok. |
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| Author: | Serge Poirier [ Wed May 10, 2006 12:11 am ] |
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Do you guys have pics of the best grain orientation for bridges ? What if the bridge patch grain is oriented one way and the grain from the bridge itself is oriented at 90 degrees to the bridge patch, wouldn't that be secure enough ? Serge |
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| Author: | TonyKarol [ Wed May 10, 2006 12:48 am ] |
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Oh, I forgot to mention that my bridge pin holes follow the saddle slot slant, so straight grain bridges are pretty good, and if I have the choice in a bridge blank, I orient them such that the grain runs away form the slot angle. same thing for bridge plates. |
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| Author: | Howard Klepper [ Wed May 10, 2006 3:39 am ] |
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Al, you are seeing the early/latewood lines as lines of weakness that will tend to split. Actually, almost all woods will split more readily on a radius of the tree (ever split firewood with an axe?). In other words, a flatsawn bridge is most likely to split along the pinholes. Least likely is rift sawn, since there is some tendency for splitting along the growth lines. But not so much a tendency as to make quartersawn bridges a bad thing. |
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| Author: | Alan Carruth [ Wed May 10, 2006 7:20 am ] |
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Classical bridges tend to split out in front of the saddle. Maing them from skew-cut wood (45 degrees or close to it) helps. An even bigger help is to move the saddle slot back a bit when you make the bridge. Instead of having only 3mm of wood in front of the saddle, you can have 5mm without any need to add mass or stiffness to the overall design, and it will hold up a lot better. BTW, ebony is a pretty splitty wood, and also usually too dense for a classical bridge. I like to end up with a bridge that weighs no more than about 24 grams, and it's hard to get an ebony one down that far. Macassar is the best bet, if you insist on a black bridge. |
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| Author: | Serge Poirier [ Wed May 10, 2006 12:17 pm ] |
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Mr Carruth, what's your take on walnut bridges, i heard that you are using them, are they strong enough? Serge |
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| Author: | Mark Swanson [ Wed May 10, 2006 2:42 pm ] |
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I have used a lot of walnut bridges and I like them. Eastern black walnut, very light. I had no troubles at all with them. |
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| Author: | Serge Poirier [ Wed May 10, 2006 2:45 pm ] |
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Thank you very much Mark, i'll be using some that i have, i think one of the pieces has the grain at 45 degrees so i should be good to go then!
Serge |
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| Author: | Martin Turner [ Thu May 11, 2006 12:25 am ] |
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[QUOTE=Alan Carruth] An even bigger help is to move the saddle slot back a bit when you make the bridge. Instead of having only 3mm of wood in front of the saddle, you can have 5mm without any need to add mass or stiffness to the overall design, and it will hold up a lot better. [/QUOTE] Good advice....I usually rout my saddle slot about 5mm back from the front of the bridge. |
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| Author: | Todd Rose [ Thu May 11, 2006 4:53 am ] |
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What Howard said. Thanks, Howard, for dispelling a popular misconception. |
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| Author: | Alan Carruth [ Thu May 11, 2006 5:51 am ] |
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I have used walnut for bridges, and it works well. Again, the key is to leave enough wood in front of the saddle slot to resist splitting: walnut is not nearly as strong on a volumetric basis as the rosewoods. Keep this in mind when making the tieblock on a classical bridge, too. It is reasonably stiff, and can be much lighter, which gives you an edge in bringing out the high frequencies. |
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| Author: | Serge Poirier [ Fri May 12, 2006 4:27 am ] |
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Thank you very much Mr Carruth, just what i needed to hear ! |
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| Author: | altec [ Sat May 13, 2006 9:11 pm ] |
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thanks a lot for the responses. Indeed i was concerned about the front of the saddle breaking off should i make the bridge perfectly quartered on a splitty wood like ebony. Quartered to 45 degree skew for those woods then ...or adjust the saddle back. (I shouldn't worry much about this as i'm going to follow a plan, but it's good to know these things.) Is wood movement a significant issue on bridges btw? I imagine the arch-ess and the width of the gluing surface should be reasonably constant through humidity... Say, will an E.I. rosewood hold up if it were flatsawn? (tangential movement is 5.8% whereas it's only 2.7% for radial.) some woods just look 10 times better when flatsawn and i was wondering if i can get away with it. 
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| Author: | Alan Carruth [ Sun May 14, 2006 2:08 pm ] |
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The aerobatic pilots say that you can do anything you want in an airplane and get away with it, until you hit the ground..... |
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