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One of my next projects is a single cone biscuit bridge wood body resonator guitar. I have order the Beard plans.
I have never built a resonator, but have the itch.

Why do resonators have a large wooden block/beam that extends from under the fretboard all the way to the tail block? Is it necessary. Can I build one with my standard double mortice and tenon joint and skip this long bar/block?

Also does anyone angle slightly the biscuit so that it can be compensated a bit?

Thanks

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Andy Z.
http://www.lazydogguitars.com

Andy, Check with Mike Franks. he has built a bunch of these and I don't remember seeing the block you mention.

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jw ( o)===:::

The bar is to support the top and cone well. The stiffer the top the better and louder your resonator will sound. You can still do a M&T/bolt-on neck and keep the support.

Does this bar also add support to the sides to keep the guitars shape similar to the dowel in a banjo? I figure since much of the top is cut away there could be a chance of the body collapsing in on itself. I never have seen a resonators insides so i'm curious...Mike

It doesn't directly touch the sides, just the top and end blocks.

The long bar is the traditional method of building. On the Nationals and a few others, that bar is actually an extension of the neck and is the mounting connection for the neck. Not sure about the current biscuit builders, but a large percentage of the square neck builders build with a open body and no separate bar. The top does have to be stiff and that is frequently done with baltic birch ply bracing or doubling up the top with it. I've build several biscuit bridge reso's without that bar and they worked excellent. The top just has to be stiff, but there are just different ways get there.
FYI, baltic birch ply makes a great top and back for a reso if you want to build on the cheap.
My favorite of all the ones I build was birch ply with plain maple for the sides.
Kent

Square neck builders use either a sound well or a post and baffle system to stabilize the top. The tops are pretty much always supported in some way.

The sound well or posts are the traditional method, but more and more builders are building with neither and going with an open box. But, as I said before, the top has to be well braced. Check the pics on the Harper and Schoonover websites for a couple examples from some top builders. A friend of mine has a Beard that he says is built with an open box as well, but I haven't seen the inside so I can't confirm that. I've built a couple this way and they are plenty strong and sound excellent.
Kent

I guess technically, the designs of the builders I mentioned braced the top to duplicate the function of the stick from the neck to tail. But my point is still, that there are different ways to make a strong box without using that stick. And moving that bracing to the top does make it a lot easier to use a bolt on neck.
Kent

Guess I started a trend and didn't even know it. I've been touting 'free' backs, braced like an acoustic for about 10 years now.

I hadn't seen that some spider guys were doing that. Thanks for the info.

Does anyone have plans for building using birch ply? I'm curious what thickness is used and where all they use it. I've heard that you have to really work to make a dobro made from real wood sound as good as one made from ply (wouldn't know from my own experience). I've been considering building using ply.......but covering real wood on the outside for a nice look. From a post above it sounds like it may help the sound for the back to be built more like a guitar where it's free to vibrate.

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Formerly known as Adaboy.......

I made up my own design and based the shape on the stock square neck cases that were available. The top needs to be pretty solid, so it more forgiving in the design requirements over and acoustic. Since the top needs to be solid, I've seen builders use 1/4 inch birch ply, but I stick to thinner stuff since it is well braced anyway. I buy the metric sized aircraft grade baltic birch ply from Wicks Aircraft Supply. I used 4 mm, which is just over 1/8", and I doubled it up in the lower bout around as part of my cone support, and it works great. I haven't tried to heat bend the stuff, but it might work. I was always concerned it might heat the glue too much and cause separations. On one, I bought 1.5 mm and laminated two sheets in the form which worked fine. The other couple I have made, I used plain maple for the sides and got an excellent result with that also.
I don't know if you can say the ply reso's sound better than solid wood ones, but there is certainly nothing wrong with ply. A lot of excellent reso's are built with ply. I think the Beard Mike Auldridge model is made of birch ply, tho they don't advertise that. And it is a killer guitar.
The wood National guitars I have had are pretty close to 1/4 inch on the top and I'm guessing are ply with veneer over them. Not sure what they use for the sides.
Kent

Thanks Kent!

To clarify, using the 4mm aircraft grade, birch ply and doubling it up in the lower bout around the cone for suport, you added no bracing to the top?

I was thinking of doing something similar but adding a thin top of real wood (I guess it would be called a laminate but I wasn't really thinking that thin). I like how you laminated the thin ply for the sides. Did you make your own mold?

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Formerly known as Adaboy.......

Y, I did brace it. I added a cross brace I made out of baltic birch just in front of the sound well and glued to the sides to support the top. Behind this on the lower bout, I doubled up the top before adding the cone support to make it stiffer. I did add bracing between this support and the neck block to make sure it was stong enough there. I was trying to come up with something original after talking to Kent Schoonover about how he braced his top. He didn't divulge much at the time and he didn't have a website, but he does now. Google kent schoonover resophonic and take a look at what he does. It's really slick.
The bracing pattern isn't as critical as it is in an acoustic. It's more about supporting the top and resisting the string pull between the neck and tail blocks and not so much about sound.
I made a form similar to the normal acoustic guitar form that I could split in half and used that for my gluing form. I drilled holes for dowels so I can put the two form parts side by side and use dowel's to pin them in allignment, so I had a wide gluing form.
FYI: Not sure if you are doing a square neck or round neck, but I've used this for both. The concepts are the same, just different cone supports and the round neck is going to need a little angle on the neck to keep your string action correct.
Good luck.