Resaw big enough for one piece back?

[charles Tauber]

Originally Posted by Bruce Sexauer

Actually, you have missed my point . . . or both points! ... The two points are: 1) our craft has largely strayed from traditional values based on knowledge and wisdom, and 2) I have not.

Thanks, Bruce, for the clarification.

I was certain that you weren't advocating the modern shift towards non-quartered woods and that you weren't jumping on the non-quartered bandwagon.

I think it will be interesting to see what happens over time to the guitars made from flat-sawn materials.

[redir]

Wow that leftover Sapele floor is one of the most impressive hardwood floors I've ever seen.

[printer2]

Full size back? Why not go for the top also? A Harmony. Back from when men were men and trees were full size.



That reminds me, I need to install my humidifier. I have some bodies I put together than are in need of some crack repair, gets dry here in winter.

[John Arnold]

I think it will be interesting to see what happens over time to the guitars made from flat-sawn materials

You really don't have to wait to assess the outcome of guitars built with non quartered woods, since there are plenty of vintage guitars to look at. In fact, Martin was one of the few to concentrate on using quartered backs and sides, and even they had moments when they didn't.
While quartered is obviously more stable, it is by no means an assurance that there won't be problems down the road. I have seen too many quartered guitars with cracks (and too many slab guitars without) to make generalizations about the performance of a particular piece of wood, regardless of the cut.
Since I obtained my first resaw in 1990, I have spent countless hours cutting red spruce and many hardwoods for acoustic guitars. That includes about 800 guitar's worth of pre-ban Brazilian rosewood, over half of which was cut from green. I had a unique opportunity to observe the entire seasoning process, and it taught me that there is wide variation in the movement of wood during seasoning. Some logs were very stable, with slab and mixed cuts moving hardly at all, while other logs would warp and twist, even the straight, dead quartered cuts. My conclusion is that without knowing the growing conditions and logging practice, it is virtually impossible to predict the stability of a particular log of rosewood.
Many of the 'zero issue' slab cut Martins I have seen were from the late-1940's, and the earlier style-21's. I am a firm believer in the practice of making every effort to build as dry as possible. In the old factory, Martin would place their rosewood backs on the radiators to dry them before gluing on the braces.
While I do prefer using quartered backs and sides, many of my guitars have had 'in between' cuts on the back, with the more vertical grain placed in the center. A few are dead slab. Some of these are over 35 years old, with few, if any issues. Undoubtedly, much of that can be attributed to proper care......avoiding extremes of temperature and humidity.

[Bruce Sexauer]

Originally Posted by charles Tauber

Thanks, Bruce, for the clarification.

I was certain that you weren't advocating the modern shift towards non-quartered woods and that you weren't jumping on the non-quartered bandwagon.

I think it will be interesting to see what happens over time to the guitars made from flat-sawn materials.

Now I am confused. I think you know where I stand. I’ve been standing on the shoulders of tradition since the beginning.

[Alan Carruth]

IMO the biggest problem with flat cut wood is the change in ring angle and curvature from place to place across the width. The larger the tree and further out from center the cut is the less of that you should see. There's still the issue of decreased splitting resistance due to the rays not helping, but that's something else. A lot will depend, too, on the tangential shrinkage rate, which varies. Also, older wood, which has already seen a certain amount of shrinkage hysteresis, might be less prone. Lots 'o variables.

As John points out, different trees come with different amounts of built in stress, and that makes a difference too. I once saw a 2x4 that was twisted from one end to the other almost 90 degrees and bent probably 20-30 degrees out of straight. I didn't get a chance to inspect it closely.

Localized differences in cross stiffness due to the incline of grain lines can sometimes be compensated for to some degree by making the bracing asymmetric. That's one of the advantages of Chladni pattern tuning; you can see problems like that.

[redir]

I have never tried bending flat sawn wood before but I would presume that would be a lot more risky then QS wood. Seems like those topographic down stream U or V shaped annular ring grain lines that poke up to the surface would easily split if they just happens to fall on a bending point.

I do have some beautiful old grown SA mahogany with the most impressive curl I've ever seen that I have been sitting on for a while because not only is it curled but it's flat sawn. I do want to use it some day though.

[John Arnold]

I have bent plenty of flat sawn sides, and the main issue is not breakage, but rippling across the grain. Even quartered sides can ripple if there is interlocked grain (ribbon stripe), a feature of quartered mahogany.

[redir]

Good, glad to hear that.

[bob531]

I agree in general that one piece slab backs are likely to crack etc.. over the years but ive seen cellos (comparing to width of a guitar back) with one piece slab backs that are crack free and other that are a mess.
Heres my personal violin that i play , slab maple back and made in 1695. A few minor cracks but not too bad for 325 years.
[IMG]DSC_0003 by bob smith, on Flickr[/IMG]

[phavriluk]

I'd long wondered why it was such a necessity to build a guitar at 40% RH when it was going to spend half its life in a 20% RH environment. Question answered. I've been building in as dry an environment as I could achieve, nice to read that I might have been doing the guitars a favor.