Bridge plate timber?

[James Mc]

The guitar I’m making for the better half is a smallish-bodied steel string (475mm long 350 lower bout and 260 upper). I don’t have a set of plans, I just drew up an outline that looked nice to me and am building it from there. I’m planning to use x brace pattern I took from a small Martin. But after a post from Bob on a different thread I took a look at the library of bracing patterns on the Unofficial Martin Guitar Forum and found I had a gap in my knowledge.

I’ve only used fan bracing before and the bridge plate on these is usually a thin slice of spruce, but looking at some of the bracing photos in the Martin bracing library it seems that a number of timbers have been used, some look very much like spruce and some look like hardwoods (and one looks like ply).

Which brings me to my question… What is the function of the bridge plate on an X braced guitar. Is it just to stop bridge rotation or is there more to it than that? Should I be using spruce or a harder wood, and if a harder wood how hard… yellow cedar, blackwood, rosewood, maple, ebony?

[Lillian]

James, the bridge plate does help the top from deforming from the tension on the bridge, but it as helps protect the top from the string balls. IF you use a pinless bridge, than you don't have to worry about the plate getting chewed up.

I can't say I remember anyone using a softwood it would get destroyed by the strings. There are several builders that laminate their bridge plate. One combination that comes to mind is maple and rosewood.

[jeffhigh]

What you are assuming is a spruce bridge plate on a X braced pin bridge Martin is Hard maple.

[kiwigeo]

I use rosewood bridge plates on both my classicals and steel strings.

[Allen]

The bridge plate is part of the bracing in an X-brace guitar. Adds stiffness, mass, helps stabilize the bridge from rotation, and most importantly helps keep the strings ball ends from pulling up through the top.

Some builders make them just a bit bigger than their bridge, while others make massive ones. I suppose each will affect response and tone in their own way. I size mine 1/4" wider to the front side of the bridge, and about 1/2" - 3/4" to the back side of the bridge. I also taper the edges of the bridge plate so their is a gradual transition from top plate to bridge plate. Doe's it make a difference? I don't know, but it makes sense to me.

I've been using Qld Walnut for my bridge plates, as I've got a heap of it, and it's so freaking hard that I don't think a ball end will ever be able to work it's way through it.

If you are in the need for some material for a bridge plate, let me know. I can send you a piece.

[James Mc]

Hi all, thanks for the help... I think I have the idea now.

Allen... thanks for the offer but it's cool, I have a couple of chunks of Q Walnut here. Great stuff if you're into sharpening planes and chisels. The strangest thing has happened, I decided to build a few guitars to use up some nice timber I already had, but since I started the size and variety of my timber stash has doubled... or tripled!

[Allen]

Yep, funny that. It won't be too long and we'll all have a selection like Martin's.

[Craig]

Yep, funny that. It won't be too long and we'll all have a selection like Martin's.

That's doubtful Allen Firstly , you'll need an aircraft hanger to store it in , and secondly he still buys up big time on a daily basis.

We'll never catch up !

[Allen]

You know what? When the swap meets are on and I some how manage to get in before Martin, it just gives "Getting Wood" a whole new meaning.

[Alfred J]

Choice of bridge plate material is said to influence tone.
Rock maple is said to have the least effect. i.e. it does not add any perceivable quality to the tone of the instrument. Martin guitars used it, then switched over to IRW for a while in the 1960s or 70s, and then switched back to maple. IRW is said to give 'punch' to the instrument (whatever that means). Some builders like it. I've used rock maple and Madagascar RW. The latter helped to add an almost reverby quality to the trebles. I also use MRW fretboards. its still available and supposed to be tonally a lot like Brazilian. For sure, QLD walnut would be a good choice.
Cheers

[Hesh1956]

The choice of bridge plate material will indeed influence the tone of the guitar.

As mentioned the bridge plate needs to be hard enough to not be prematurely worn/damaged by the string balls. It also greatly helps to NOT use slotted bridge pins. Slotted pins position the string balls more on the edge of the plate's pin holes where unslotted pins push the string balls more onto the plate resulting in less wear over time.

Think of the bridge plate as the lower half of a hot dog bun. Between the bridge and the bridge plate is the top and both the bridge and bridge plate are the first step in transferring the energy from the strings to the sandwiched top.

So the material that the bridge plate is made of, IMHO, is every bit as important as what we make our bridges out of when it comes to having low dampening and good vibrational energy transfer.

Martin used maple for many years and started using rosewood on some models in the 60's.

Depending on what is available to you of course you want to use a tough wood, not too heavy or dense with low dampening, and resonant as well. Avoid positioning the plate so the where the pin holes will end up is along the grain of the plate's orientation - this can result in a split plate. Rift sawn may be a good idea too IMHO but I can't prove it....

For bridge plates I use in order of preference BRW, Honduran Rosewood, and Osage Orange. Maple is a great choice too.

[Stephen Kinnaird]

Here's a vote for Padauk, which is both musical and hard.
Plus, it's usually lighter than rosewood.

Steve