Bridge Grain

[mikejdexter]

When making a bridge for a DB, should the grain of the bridge be in line with the grain of the top or at right angles to the grain of the top? Or does the direction of the grain not matter? Any thoughts on this?

[Turnaround]

Generally, the bridge is cut from quarter-sawn mateial, which means the "grain" will be parallel to the strings. So the flashy part of the wood (where the medullary rays are exposed) will be on the two faces of the bridge.

Clear, yes?

[drurb]

Okay, I don't know much about wood but when I look at bridges, the lines of the grain go left to right (perpendicular to the strings). What am I missing?

[1st Bass]

Not missing a thing, Drurb.

[Turnaround]

Originally Posted by drurb

Okay, I don't know much about wood but when I look at bridges, the lines of the grain go left to right (perpendicular to the strings). What am I missing?

The problem is in what is meant by "grain". It's a pretty generic term and means different things to different people.

Some people regard the growth rings in wood as being the "grain" while others reference the fibre orientation. What I intended to communicate is the pattern of lines when looking at the edge of the bridge runs the same direction as the strings. That will only occur if the wood is quarter-cut. Otherwise those lines will run from the foot to the crest of the bridge.

Quarter-cut is what is needed. And BTW, convention has it that the bridge should be laid out so that the growth ring spacing is wider at the feet than at the crest.

I hope that's clearer.

[forester]

Originally Posted by Turnaround

Quarter-cut is what is needed. And BTW, convention has it that the bridge should be laid out so that the growth ring spacing is wider at the feet than at the crest.

I hope that's clearer.

+1 and that descibes texture...and can be done only through ocular inspection by experienced manufacturers who can map out yield,minimize waste,and produce quality products for all the members in the string family.

[drurb]

Originally Posted by Turnaround

What I intended to communicate is the pattern of lines when looking at the edge of the bridge runs the same direction as the strings.

Ah, the edge of the bridge. Now it all makes sense. When those lines run parallel to the strings, the lines on the top surface run perpendicular-- as in the picture I posted.

Thanks.

[Cody Sisk]

Originally Posted by drurb

Okay, I don't know much about wood but when I look at bridges, the lines of the grain go left to right (perpendicular to the strings). What am I missing?

You're missing a bow quiver, mute and dampit..

[mikejdexter]

Many thanks everybody for your good input---question answered.
Mike

[fdeck]

Originally Posted by DallasStrings

You're missing a bow quiver, mute and dampit..

Also, I see not a trace of rosin dust.

[William Hoffman]

Originally Posted by Turnaround

...Some people regard the growth rings in wood as being the "grain" while others reference the fibre orientation. What I intended to communicate [by "grain"] is the pattern of lines when looking at the edge of the bridge runs the same direction as the strings. That will only occur if the wood is quarter-cut. Otherwise those lines will run from the foot to the crest of the bridge.

Quarter-cut is what is needed. And BTW, convention has it that the bridge should be laid out so that the growth ring spacing is wider at the feet than at the crest...

Does anyone know: Is it also conventional that the center of the growth rings should be at the center of the bridge blank? I was marvelling at the grain on my new bridge, and the center of the blank shows it was cut near the growth ring center. Is this a standard cut for a bass bridge?

[forester]

the way the face is opened is standard practice, the texture that you see is a crapshoot,( unless you saw specific.) the rings can be evenly spaced or tight and many times both, just a growth record.

unless i'm mistaken the photo shows vertical texture, i'm beginning to suspect that horizontal texture has some built in drawbacks. does your bridge have a history of anything unusual?

[William Hoffman]

"Vertical texture" -- if by that you mean the growth rings are running vertically (or as some one else said, "parallel to the strings"), yes, that's what I have in this bridge. Turnaround used the term "quarter cut", though I am not sure what that exactly refers to.

The new bridge works very well. The bass sounds louder and clearer (the new bridge was the only change made -- same strings, sound post in the same exact spot, bridge in same position, etc.). The new one is of harder maple than the old bridge. On the old one the growth rings are similarly "centered" and running vertically, but not as visible.

It is a crap shoot, every bridge is different. But you seem to be saying that vertical is better. Is that because vertically running grain transmits the vibrations better?

[forester]

quarter sawn refers to the method of opening the log with the saw lines radiating out from the center similar to the spokes in a wagon wheel, the medulliary rays which follow the same pattern are split back and forth and give that pretty fleck and smear of darker color.
with the size of a bass bridge there is a greater chance of "runout" when manufacturers optimize their yields.

as far as vertical texture,i think the jury is still out,but it stands to reason that the denser column of material running from cap to foot would be a better conduit for energy.

here's what i have been questioning lately,
i've been getting a lot of violins and violas cycled back that i put bridges on 3-4 yrs ago. the string heights appear to be settling lower. the tops are not sinking etc. i'm starting to believe the bridge is shrinking, reinforced by the fact that stacked horizontal rings would naturaly move up or down and that in the end, under tension tend to come up short.
with a bass bridge you can compensate with adjusters, not so with the other string family. if i pulled a violin or viola bridge with the same pattern as your bass bridge it would be a "blem". i need 3-4 more yrs of observation before the i form my own verdict.
hope this helped.

[William Hoffman]

So quarter cut refers to a log cut lengthwise in four long pieces, each with two sides forming a right angle and a round side. Makes perfect sense now.

The picture I posted above couldn't be from a quarter cut. If you look closely, the roundness of the center ring clearly wouldn't fit into a quarter cut piece. Rather, it must've been fairly close to the center of a half cut. Is half cut an accepted conventional cut for bass bridges?

Btw, the bridge in the picture is a Despiau "Superieur" *** (three little trees) blank. It is the best quality bass bridge I could find.

[forester]

so you take that quarter (round side down) and butt either flatside to the fence and start sawing straight through at the desired thickness. when you really have it together, you have several hundred quarters,end to end running through a carrousel saw putting out about 12,000 bdft a shift.
(i used to ship quartered white oak all over the world.)

i can't speak for the manufacturers sawing strategies but my line of thought is that your bridge came from the perfect spot,one or two clicks closer and it would have been in the center of the heart, and that could have been problems.

i could bring up supply side thoughts, but that always causes a ruckus.

peace

[William Hoffman]

Thanks for sharing.

[arnoldschnitzer]

Originally Posted by forester

here's what i have been questioning lately,
i've been getting a lot of violins and violas cycled back that i put bridges on 3-4 yrs ago. the string heights appear to be settling lower. the tops are not sinking etc. i'm starting to believe the bridge is shrinking, reinforced by the fact that stacked horizontal rings would naturaly move up or down and that in the end, under tension tend to come up short.
with a bass bridge you can compensate with adjusters, not so with the other string family. if i pulled a violin or viola bridge with the same pattern as your bass bridge it would be a "blem". i need 3-4 more yrs of observation before the i form my own verdict.
hope this helped.

Neck heels are end grain, which absorbs and gives up moisture more readily than face grain. In a humid environment, the neck heel expands, causing the strings to go higher. In a dry environment, it shrinks, and the strings go down. Most commercial instruments are made from wood that is semi-dry. As the wood dries more, the neck heel shrinks and the string height goes down. This is especially prevalent in cellos. Sometimes the neck heel also shrinks away from the sides, causing a loose joint.

[forester]

thank you arnold, that's movement i hadn't considered.
in the future,i'll suggest the boys source the instruments last location and see if a pattern develops. i'm not alone in noticing the change in set-up. many haven't had a note played through them and sit cased on the shelf.
from what you're saying it would be a safe bet might be on the western states.

[gbaker]

Originally Posted by forester

. . . i'm starting to believe the bridge is shrinking, reinforced by the fact that stacked horizontal rings would naturaly move up or down and that in the end, under tension tend to come up short.

The first bass bridge I cut (before I ever looked at a commercial bass bridge) I positioned with the grain (tubes) vertical like a stud in a wall. Moisture change has much less dimensional effect in this direction and I reasoned that moisture stability would be more important than the unlikely risk of splitting presented by the large diameter strings. I was surprised to learn "correct" bridge grain is positioned as a beam rather than a stud. That bridge is still in use and there has been no problem with it.

Also I think that vibrations are transmitted more efficiently through end grain than side grain; and that maybe bass bridges are built that way to follow violin design, with thin strings that could split the bridge.

But who am I to question 700 years of evolution, right?