Official Luthiers Forum!

I have wanted to try a wedge guitar for sometime. A few years ago I actually asked Linda Manzer, because I believe in giving credit where credit is due, if she had any problem with people using her idea, which she did not. So, I'm curious how builders approach the wedge back. One builder told me he just made a regular body and then sanded in the wedge before doing the kerfing. A wedge guitar that I looked at once seemed to have the wedge only go to about the centerline of the back. I'm interested in whether the body is thicker than normal on the fat side, just how much wedge is common, and how that wedge is accomplished, as well as any hidden pitfalls. I've seen what looks like to be about 1" of wedge a couple of times. I'm doing a 16" wide body. Thanks, Bob

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Patented in 1969 by Mr. Walter E. Smith of Caldwell, Idaho - about the time Ms. Manzer was in high school. So it's fair to say that the wedge was invented by Mr. Smith and popularized by Ms. Manzer.

https://www.google.com/patents/US3426638

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A constellation only takes shape when one maps the whole.
- Beth Brower

Yeah just cut/plane the left or bass side down to where you want it and glue in the linings. It's really not any different from doing a normal guitar. On the one classical guitar I built I didn't make the treble side thicker but it does seem to make sense that you should.

My last build was a wedged OM cutaway (fan fret) - aimed for a 25mm difference bass/treble, which seemed about right from my research (but ended up 23mm to keep my target tail depth)
With the 15' or more back radius, the treble side can look flatter than normal.
Any more can lead to potential problems with binding ledge depth differences bass to treble sides using my tower binding jig/doughnut set-up, and even at 23mm, I had a bit of handwork to do to even them out, especially at the neck end of the bass side.
I just propped the rims up to give me the difference in depths before marking the line round the back, much like normal in it's radius dish.
Then spokeshaving/block planing to the line and sanded the rims before fitting the kerfed linings, soundboard side is as per a normal guitar of course.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Thanks for the replies. It does not sound too difficult. The player originally wanted me to do this in Brazilian, but luckily I have very nice Indian RW that I was able to talk him into. I did not want to have to replace a Brazilian set if I screwed it up. Fortunately I have some very nice old Indian RW sets. Nobody in Hawaii wants rosewood normally, so I still have sets that I moved here with 35 years ago. Nice purple stuff.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Yep, it's no big deal. Just put the back on crooked! I use about 15mm differential between the thick and thin sides, which seems enough. As others have said, take care with things like binding channels. I use two different settings on my tower type rig, bass and treble sides, then hand blend them. Also watch out if you use a router to flush trim the top and back. If you use a live back, I get the impression they work a bit differently, possibly due to the pressure building in the box in a different way. But that's speculation.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I'd like to clear up something regarding Linda and the wedge body.

When she came up with the wedge as part of the design for the 'Pikasso' guitar Linda had never seen anything like it, so, as far as she was concerned, it was her invention. She didn't try to patent it. At some point around that time she had a conversation with Cumpiano and told him about it. Apparently it slipped his mind. Some time later he had a client who was having right arm problems, and came up with a wedge body as a solution. Having forgotten the conversation with Linda, he claimed it as his invention. This set off a priority debate, until the two of them got together and straightened it out. After that Linda emphasized the idea of the 'Manzer Wedge', not as a way of making money, but simply to claim the priority she felt she had.

Several years ago one of my students did a patent search on guitars, and came up with the Smith patent. I mentioned it on line, and eventually the word got back to Linda, who contacted me. I sent her a copy of the patent, iirc, and we had a cordial exchange. She said that Smith's reasoning was exactly the same as hers.

So, this is an example of great minds thinking alike. There is no doubt the Smith got the patent, although, of course, that doesn't mean that nobody else used the idea before him. There is also no doubt that, in the larger guitar world (or puddle) it was not widely known until Linda came up with it. They both deserve some credit.

I did it once. It was an OM cutaway with a one-inch difference.

I had a very difficult time getting The Binding Ledges right. It wasn't the difference in depth, it was the squarenes. It seems like the bottom part of the ledge tilted away from the vertical part at a greater than 90 degree angle. I could not figure it out for the life of me. I even started a thread on here but no one had any ideas. Eventually the only way it worked was by trimming the inside corner of The Binding. Not just the normal amount of breaking the edge but I trimmed about 75% of the bottom. My rabets were an exact fit for my binding, so I didn't have to worry about scraping through too much.

I used my usual binding jig, bearings, cradle, average squared sides. Etc

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Pat

Pat, I wrote this piece on the forum a few years back, now edited a bit for better clarity. It may be the problem you've been running into. It happens when you can't keep the binding cutter axis both parallel to the sides AND perpendicular to the local plane of the back (usually). Tends to be more of a problem with high curvature backs on guitars with cutaways and likely even more of a problem with wedge cutaways. Apologies for the "basic" drawings:




I don't know of a binding system that will follow both the local dome of the back (i.e. registering off the back) and stay parallel to the sides around a cutaway. I use a tower type system which reliably gets around most problems, then do a bit of cleanup with a chisel or scraper, as required, on the ledge bottoms. What you do by taking the inside edge off the binding works too, of course, and you can see the reason why.

The problem exists to some degree most of the time, but usually too small to cause much trouble. Just a small bevel on the inside edge of the binding (which should be done anyway) is usually sufficient to eliminate the issue. But high curvatures and tilts can be a problem.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

This is an example that makes me wonder about the pursuit of credit. Ah the vanity of it all.

Andy

Wow, that's totally it! Thanks Trevor.

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Pat

I suspect all of us wish to be seen as having made some unique contribution to our craft, and certainly, Ms. Manzer can claim a broad range of contributions and accomplishments in addition to her popularization of the wedge instrument body.

As my smile lines have edged towards becoming something a bit less transient in nature, vanity seems like an entirely reasonable and justifiable motivation for investment in those same preparations and potions that just a few short years ago seemed unnecessary to feed anyone's - and much less my own - self-regard.

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A constellation only takes shape when one maps the whole.
- Beth Brower

It's always been very important to me to honor those who came before us with attribution when it's due. So much so in my view is my own belief that these folks including Linda and many, many others deserve lots of credit I'm willing to error on the side of providing attribution even if there may be some question.

There is a tradition that Linda enjoys that when one of us wants to contact her for either advice or permission and I not going to get into any crap about if permission is needed.... that the one doing the contacting send her a bottle of nice wine from as close to where we live as possible.

This is not new, it's been a tradition associated with Linda for some time. She has MANY, many bottles of local wine as a result.

I'm not in the business of telling others what to do and personally I see no value in even questioning the original origin of the wedge shape, to me Linda has brought it to the forefront in the times that I live in and that's all I care about.

With this said if I was going to make a wedge guitar I would indeed contact her, she's great by the way and not only would I have a new friend Linda would at some point have the best bottle of local wine that I could find.

Likewise if I built a guitar with Trevor's bracing he would be receiving what ever I find out that he likes, scotch, wine, etc.

Lastly if you don't get out much and associate with others in the trade I would suggest that you reconsider if you have any opportunities to do so. Once you can put a face, personality and even friendship in your mind's eye when considering some of the names in our trade it's pretty easy to know what to do and when to do it.

Although Smith came up with the idea, he didn't do anything with it. Where are these instruments? I'd never heard of Smith until Al posted about the patent years ago. I think its fair to say that Linda is responsible for its popularization, and to that end she deserves credit.

Totally did this by accident a few years ago but liked it. Now learn that it turns out my mistake has been patented a long time ago. Just goes to show, even when you F up you may still be on the cutting edge of innovation 30-40 years ago.