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Does anyone orient the grain of their bridge plates to run parallel to the top? It seems to me that this would add a little longitudinal stiffness and allow the plate to be thinner, thus shaving a few grams of weight off.

I could see the plate and top being more likely to split using this orientation, but is that really a concern given the bridge directly above? If so, how about a very thin two-ply bridge plate with each plate running cross-grained to the other with the outside plate parallel to the top?

Am I missing something?

I am sure this has been discussed before, might worth finding that thread.

I think that the strings digging between grains might be a problem?

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Build log

Frank Ford swears by "parallel grain" bridge plates.
I think he goes into why on frets.com
-C

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Freeborn Guitars
and home of BeauGuard©

I've been using parallel grain plates for the past few years, but Mario has
brought some advice and experience that has had me seriously rethinking
that. It makes excellent sense at first, but with a bit more thought lately I'm
beginning to realize some likely flaws to the idea. There are a number of
people who have started using parallel grain in recent years, many with good
success. Still, I think I'm going back to standard grain orientation.

As to laminates, there's a lively discussion on another forum about this very
topic right now. The general consensus is that rather than getting the best
of both worlds, you get the best of neither.

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Eschew obfuscation, espouse elucidation.

I think frank doing this on a repair point makes sense. Wood with the grain running opposite the grain of the top can twist and cup and this could cause some damage to the top. Remember he's matching a new plate to a well seasoned guitar. On a small piece of wood with the grain running front to back this plate will not probably twist or cup at all. Any shrinking or expansion will happen from end to end and it will be very little. And the top would probably be able to handle this end to end movement better then a piece that had opposite running grain and go along for the ride. Thinning the bridge would just probably add to the posibility of faster plate wear and future damage. Why risk it.

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Guitars, guitars and more guitars.

Personally, I think the bridge area is an important place to have a lot of cross grain stiffness. A traditional bridge plate helps with that.

Mark

I agree with that myself on new construction. Frank ford is not building he's repairing though and they are two different worlds. So someone basing doing this just because he does needs to understand that hes doing it for a different reason. He's not doing it because he might be able to thin the plate or because he thinks it adds longitudal strentgh. He believes this way will deter future problems and the best way to add a new plate to a very old guitar.

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Do you need more cross grain stiffness than the bridge provides? Is it a bigger plate? That is interesting to me, I have always tried to make the longitudinal stiffness stronger there. David, what are the drawbacks you have found to a parallel plate?

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Good discussion!

I would think that a laminated bridge plate, or bridge for that matter is like adding insulation to a wall and would inhibit vibration transfer.

It's an issue I'm still trying to clear my thoughts on to be honest. Yes, it's
fair to assume that the most stiffness would be desired parallel with the
strings. When you think about the bulge that so often develops behind a
bridge however, how is that bulge shaped? The fact is that the bulge is
just as or often more significant across the top grain (between the X-
braces) as it is along it. Is it wiser to attempt to stabilize the top
crosswise between the X-braces, or lengthwise? I'm beginning to lean
back toward the cross grain orientation, as I worry the parallel grain plate
may allow more bowing across the grain.

It's a complicated area of the top to think about, and I'm doing a lot of
wondering out loud here. For the moment I am mulling over only
structural ideas, tone completely aside for the moment. Clear one cloud
at a time.

What are the essential structural functions of a small bridge plate that
does not extend significantly behind the bridge? String end support,
obviously enough. But structurally I don't know if it should be relied upon
to significantly stiffen a wide center region of the top. Rather, I think it's
job is more importantly to stiffen the more local area of the top plate
directly where the bridge is anchored. This of course to prevent
premature warping and bridge lifting which would happen almost
immediately without a bridge plate.

I'm moving back toward emphasis on stiffening the top more across the
grain, and relying more on the braces at the ends of the plate to help
prevent it from twisting. Looking at it from this view point I can easily find
argument that a small parallel grain bridge plate could be less resistant to
the bulge.

This is one discussion in which I would love to hear more from folks like
Mario, Alan, Rick, Todd, and anyone else likely to have opinions and/or
experience with this.

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Eschew obfuscation, espouse elucidation.

I'm also trying to wrap my head around it all. Also thinking out loud...

Thinking structurally, does a top ever fail due to a lack of cross-grain strength at the bridge plate? I would think if the top's going to fail here, it would be because of a million things before a wood failure across the grain.

On the other hand, some think cross-dipole motion is wasted motion, as one side is always out of phase with the other. That camp would seem to want to maximize cross-grain stiffness.

I don't see durability as an issue either way if the wood is sufficiently hard and the gluing surface is sound... again, you've got this relatively massive and stiff bridge overhead to keep things together. I would be interested to hear if any seasoned repair people have seen otherwise.

If you think of the bridge plate as having a significant effect on keeping the top from bellying (after some minimal thickness to effectively anchor the string ends without distorting), then it follows that the added longitudinal stiffness of parallel grain could allow for a thinner plate and shave off a little weight.

I did some experiments a couple of years ago on my test body where I tried several sizes and shapes and materials of bridge patches on the same guitar. I have a flap in the back of the guitar so it's easy to get in and work on things. I'd be surprised if you can generalize and say that, for instance, a stiffer bridge patch will have "X" effect on all guitars. I think it depends on everything else that's going on in that area.

But I found that small changes in that area have big effects on sound.

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http://www.chassonguitars.com

Hum? I was taught to use riff cut plates and run the grain perpendicular to the tops grain. The debate on the grain direction is interesting and I see advantages to each. But here is some thing I think is important.

The riff cut plate is less likely to split or crack from the loading of the string ball.

I would assume that a 3/8" thick piece of wood (the bridge) glued cross
grain would give all the additional reinforcement necessary....

Here's Franks discussion on the topic. Isn't the search function great!

http://www.luthiersforum.com/forum/forum_posts.asp?
TID=10014&KW=Frank+Ford#forumTop

-C

_________________
Freeborn Guitars
and home of BeauGuard©

http://www.luthiersforum.com/forum/forum_posts.asp?
TID=10014&KW=bridgeplate#forumTop

_________________
Freeborn Guitars
and home of BeauGuard©

HERE is a hot link.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

[QUOTE=Hesh] Good discussion!I would think that a laminated bridge plate, or bridge for that matter is like adding insulation to a wall and would inhibit vibration transfer.
[/QUOTE]
Hesh this the one thing I never understood about using laminated neck and heel blocks. Many people are. Don't these inhibit vibration also? I would think so.

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Guitars, guitars and more guitars.

[QUOTE=Chas Freeborn] http://www.luthiersforum.com/forum/forum_posts.asp?
TID=10014&KW=bridgeplate#forumTop[/QUOTE]

Nice tip in there from Frank Ford to treat the bridge plate holes with CYA glue. It's a fantastic idea, as are so many of his ideas.

That poses a question. is more beneficial if a neck dampens vibration through it there by using up less of the kinetic energy created by the strings, or if a neck actively vibrates there by using up more of the energy produced?


A-L-A-N!!!!!