Resaw big enough for one piece back?

[Skarsaune]

We milled up some lovely walnut slabs over the weekend.

While stacking / stickering them in the barn, it occurred to me that several of the pieces were big enough to cut a true one piece back from. The wood would be fairly well quartered on the outside, going more to flat sawn in the center. Proper sawing would yield nicely quartered sides to go with.

I've resawn two piece backs with my little bandsaw (14" total capacity with the riser). These sections run to 27" wide - knock off the sapwood and there's still 20" of walnut to resaw.

The only solution I could think of to cut a piece that wide is a friend with a band saw sawmill. I'm not sure he could cut 1/4" slices accurately but I'll ask. I'm sure there are bigger bandsaws out there that could do this, but I don't know that I've ever seen one.

Any thoughts on constructing a guitar with a one piece back? Any bright ideas on getting it sawed, so i don't have to thickness sand a 2" plank?

Not like I'm in a rush. I've got a a few years while these are air drying to figure it out. That might let me build the guitars I already have planned, too.

[charles Tauber]

I have fond memories of having visited Gurian in 1978. At that time, a few years before the fire that ultimately ended the business, Gurian was one of the world's largest suppliers of instrument woods. They had a two-story bandsaw for re-sawing lumber into instrument parts.

I've not seen such a large bandsaw since then but I'm sure you could find someone with the ability to resaw 20" wood.

Making a one piece back you lose the appearance of symmetry, an aesthetic choice. Otherwise, the only issue that comes to mind is stability of such a wide unquartersawn piece of wood. Potato chipping of the piece can add difficulty in working with it.

For final re-sawing, you should get greater yield by sawing to less than a 1/4" thickness.

[Bruce Sexauer]

With so many makers shunning the tradition of quartersawn materials, a one piece non-quartered back may seem like a good idea, and may be marketable. But I wouldn’t do it because the back is already highly stressed potentially unstable component and a one piece non-quartered back membrane is asking for trouble.

[Alan Carruth]

As Bruce says, one-piece backs are mostly shunned due to stability issues. Where the grain lines curve a lot, as seen on the end grain, there's a high tendency to cup across the grain due to the different rate of shrinkage across the grain between flat cut and quartered areas. If the grain lines are parallel to the surface of the wood that won't happen, but for a flat back that implies a tree of infinite diameter. There's only one of those in the universe, and it would take forever to cut it down... Also, keep in mind that the medullary rays help tie the wood together and prevent splitting to some extent in quartered stock. I flat cuts you lose that advantage too. Bird's eye maple, which has to be flat cut to show the eyes, tends to split badly, and with the meandering grain the splits are tough to fix. On top of that, cross grain stiffness falls off fast as you approach skew cut, with the ring lines at 45 degrees to the face, so a flat cut back tends to have large variations in cross stiffness from point to point.

Several years ago our local luthier group opened a meeting at a nearby sawyer's yard. They had just pulled a large log of very curly rock maple out of the kiln, brought it in, and cut off the bands. They pulled off the two outside slabs and left it on the pallet. It was some of the curliest maple I've ever seen; the figure showed up strongly even on the flat cut face. Every time I walked past it I stopped and drooled for a bit, thinking of the one-piece archtop backs that slab would make. In that case the ring lines would parallel the carved face of the back, and cancel out most of the problems. I had to keep reminding myself that I have a room full of stuff that needs to be made into guitars. I was told later on that the yard sold all of that log in about a week to the local furniture makers. There has been some stunning Shaker style stuff coming out lately. Luthiers get GAS too...

[Quickstep192]

Here ya go!

https://www.rockler.com/laguna-lt37-...oat-x-24-resaw

I'm sure you could make up the cost by selling one-piece backs and doing custom re-sawing!

[Quickstep192]

Originally Posted by Alan Carruth

Several years ago our local luthier group opened a meeting at a nearby sawyer's yard. They had just pulled a large log of very curly rock maple out of the kiln, brought it in, and cut off the bands. They pulled off the two outside slabs and left it on the pallet. It was some of the curliest maple I've ever seen; the figure showed up strongly even on the flat cut face. Every time I walked past it I stopped and drooled for a bit, thinking of the one-piece archtop backs that slab would make.

I was told later on that the yard sold all of that log in about a week to the local furniture makers.

Almost seems a shame that it became furniture instead of a Carruth Archtop...

[Skarsaune]

Nothing like the AGF for some no-kidding expert opinions! Thanks guys.

I'll stick to the quarter sawn backs. Those I can re-saw with existing equipment.

Thanks again.

[charles Tauber]

Originally Posted by Bruce Sexauer

With so many makers shunning the tradition of quartersawn materials, a one piece non-quartered back may seem like a good idea, and may be marketable.

Originally Posted by Alan Carruth

As Bruce says, one-piece backs are mostly shunned due to stability issues.

I think Bruce's point was the opposite: many modern makers are using non-quartered materials, dispensing with traditional practice. For that reason, one might be able to sell a guitar with a flat-sawn back, where, traditionally, buyers would not have purchased such a guitar.

The question that arises is, is it unnecessarily restrictive to not use flat sawn materials? Is there an epidemic of guitars that are falling apart because flat sawn materials are being used? Or, it is that those with flat sawn guitar backs need to humidify the heck out of them to minimize wood movement?

[redir]

I prefer QS myself though and have never used anything that wasn't QS or maybe drifts away from vertical grain to the outside. I have built a couple guitars with one piece backs and tops too but they were very small parlor guitars and the wood was vertical grain across.

I've come across some vintage guitars that were flat sawn BRW. So even back in the day it was certainly done.

[JonWint]

This horizontal bandsaw may handle one-piece backs. Stickered wood is walnut headed to Gibson.

They (Hearne Hardwoods) have a 67" bandsaw also.

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leftover Sapele for flooring:

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[Skarsaune]

Originally Posted by Quickstep192

Here ya go!

https://www.rockler.com/laguna-lt37-...oat-x-24-resaw

I'm sure you could make up the cost by selling one-piece backs and doing custom re-sawing!

At $12K, that's a lot of resawing to do, lol. Nice machine, though.

[Mark Hatcher]

Charles mentioned the symmetrical look you get from two book matched back halves. There is also the importance of symmetry for the sound response you get. If the back is quartersawn on one side leading to flatsawn on the other that will deaden the response of the back. Of course, if you make thick reflective only backs that might not make such a difference. If you are trying to take advantage of an active back I'd stick with the more symmetrical book matched set.
If you want to easily check the importance of symmetry take a typical back half rectangular blank and tap it and listen the the range of tones and sustain you can get from it. Then cut a corner off and try it again. Or get a corner wet. Or taper part of it's thickness.

[ruby50]

That giant bandsaw at Hearne Hardwood in Oxford PA (40 miles west of Philly) came from the Philadelphia Naval Shipyard were the Navy built warships from 1871 til about 2000. The saw was used to cut teak logs for the decks of ships. Even some aircraft carriers had teak flight decks.

We watched them demonstrate that saw on a 60" walnut log. It is not computer guided, but the Amish guy they runs it has a small notebook and a pencil for calculations. He sawed that walnut log in to the center from one edge, flipped the log, then came in towards the center from the other edge. All pieces were 2-1/2" thick, even the last one.

Hearne also has amazing wood for sale to mortal humans like us. I fell in love with a b+s set of curly Koa, but almost had a stroke when they said $1200.

Ed

[Bruce Sexauer]

Originally Posted by charles Tauber

I think Bruce's point was the opposite: many modern makers are using non-quartered materials, dispensing with traditional practice. For that reason, one might be able to sell a guitar with a flat-sawn back, where, traditionally, buyers would not have purchased such a guitar.

The question that arises is, is it unnecessarily restrictive to not use flat sawn materials? Is there an epidemic of guitars that are falling apart because flat sawn materials are being used? Or, it is that those with flat sawn guitar backs need to humidify the heck out of them to minimize wood movement?

Actually, you have missed my point . . . or both points! The market has IMO led the lutherie community astray by supporting aesthetically interesting wood which actually would have had little or no place in out work as little as 50 years ago. Dinosaur that I may be, I have stubbornly clung to the "old" standards, and intend to do so till it's over. The two points are: 1) our craft has largely strayed from traditional values based on knowledge and wisdom, and 2) I have not.

As far as a failure epidemic is concerned, if/when the grid lets us down to the point where humidity can be artificially controlled, then I expect it to hit the fan . . . as it were .

[srick]

Originally Posted by charles Tauber

I have fond memories of having visited Gurian in 1978. At that time, a few years before the fire that ultimately ended the business, Gurian was one of the world's largest suppliers of instrument woods. They had a two-story bandsaw for re-sawing lumber into instrument parts.

For some strange reason, I don't really remember the bandsaw as much as I remember Michael's wife, Dixie. But then I was 25 years old <LOL>!

Seriously - many fond memories of the place too. At one point, I built dulcimers, but never made my way into the main event of buidling guitars.