Official Luthiers Forum!

Greetings all,

This is my first post - please be gentle with me!

In the process of thinning some quarter-sawn maple to around 2.5mm to act as a bridge plate, it struck me that it's stiffness across the grain is far less than the longitudinal stiffness of the spruce top whose deflection it's meant to help protect against the torqueing action of the bridge. As the grain of the bridge plate typically runs perpendicular to the grain of the top, wouldn't this suggest that it serves little purpose in that regard?

Is there merit, therefore, in a bridge plate whose grain runs parallel to that of the top plate? Or, to add stiffness in both directions, maybe a bridge plate consisting of a two-layer laminate, with the grain of each laminate running at 90 degrees to the other?

What a fantastic resource this forum is - how it escaped my attention for so long, I just don't know! Having begun my guitar-building exploits before the internet was available, I look back in wonderment at how slow the learning process was for me in those early days. Haven't things changed!

Cheers
Pete

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Cheers
Pete

first never use quarter sawn for bridge plates. On a bridge plate the path of failure is in compression by the ball ends of the strings. so use riff or skew sawn. far greater compression strength. second if the grain of the bridge plate is in line with the top the greater the chance of splitting along the grain line of the bridge plate caused by the compressin load of the ball ends

Hi Pete,

Welcome to the forum! And right you are about the days before the internet....

Anyway, if you search in the old threads, you should find a bunch of discussion about the bridge plate orientation.

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Build log

Thanks guys!

I guess I should familiarize myself with the search function before I post! As you've suggested, Alexandru, there's a lively discussion on this very subject in the archived threads.


Cheers
Pete

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Cheers
Pete

Thanks guys!

I guess I should familiarize myself with the search function before I post! As you've suggested, Alexandru, there's a lively discussion on this very subject in the archived threads.


Cheers
Pete

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Cheers
Pete

no. never regret asking a question prior to research. We may suggest you search the archive to find more on the topic but we do not tell members or visitors around here to search the archive before posting. That is not our style.

Hello Pete Brown,
Glad to see you here. I hope we get to hear more from you too and you sound like you have many stories to tell of guitar building. I for one would love to hear them.

Anyway, ask all the questions you can, cause I'm only on my second build and need to know more. I crave more and more everyday.

It is an interesting question you ask and one I haven't pondered upon yet. There has been some talk on here about a laminated bridge plate. The Search function can be so overwelming at times and it seems like you're so all alone in there.

Okay den, don't forget to post LOTS of pictures of you builds too.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

Laminating the bridge plate makes sense to me, and is what I and many others do. I think of the whole lamination as including the bridge and the top, so, calling the grain direction of the top "long grain", mine go like this, from top to bottom:

bridge - cross grain
top - long grain
1st layer of BP - cross grain
2nd layer of BP - long grain
3rd layer of BP - cross grain

The 2nd (middle) layer of the BP, whose grain is parallel to the top, is twice as thick as the other two layers, so that it is adding significant stiffness in the "long grain" direction. By laminating it with cross grain layers, the possibility of the BP splitting is slim to nill. By alternating grain directions and making it more-or-less symmetrical from top to bottom, I believe it is the most stable. I laminate the BP in a radius dish (and glue it onto the top in a radius dish as well, of course).

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I do like the idea of laminating the BP I may try that in the future. But in the mean time I always used flat sawn hardwood for the plate on steel strings and a cross grained quarter sawn spruce patch on classical guitars.

This article is about plate replacement, but go on to the second page where he discusses making the new BP.
http://www.frets.com/FRETSPages/Luthier ... rplt1.html
-C

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Freeborn Guitars
and home of BeauGuard©

Hi Pete - I just want to welcome you to the OLF my friend!

Great to have you here.

I also think a "luthier-made custom-laminated bridgeplate" makes a lot of sense, until the word gets out that you are using "plywood" for your bridgeplates.
What's a builder to do?

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https://www.facebook.com/profile.php?id=100008907949110

Thanks all for the thought-provoking responses.

With divergent opinions on grain orientation and conjecture as to the pros and cons of laminating the bridge plate both here and in the archived threads, it seems this is yet another aspect of our art/craft/science where a definitive answer isn't available, although the argument for flat or rift sawn stock is hard to argue with.

At the end of the day, each of us chooses the solution which best appeals to our own very individual sense of logic.

Cheers
Pete

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Cheers
Pete