Flat Sawn vs. Quarter Sawn Neck Block? Plywood tailblock?

[Mark Gunter]

Not wrong Adrian - in general, not great joints. It is a woodworking issue, not strictly a lutherie issue. Have all chairs been made wrong for a few thousand years? No, the practicality of use dictates that leg grain runs vertically while stretcher grain, seat rail grain, etc runs horizontally. But any maker worth his salt knows that these grain orientations are precisely why joints in chairs do not stand the test of time as well as joints made with wood where the grain is oriented in one direction. It does not require much thinking to understand why joints with opposing grain are problem joints as to longevity of joint integrity when you think about the direction of wood movement and apply the miniscule movements over decades.

I did not say it was wrong to make that joints that way. I have noticed the grain orientation on guitars I've reset necks on, and I know that it was wide practice to make neck blocks like that on guitars, and nowhere did I say it was wrong. What I wrote was what you have already quoted above,

I have very strong reasons for this having to do with the longevity of a quality build, in my opinion, due to the minuscule movements of wood over the decades, and based on many years of fine woodworking experience.

[Mark Gunter]

Grain orientation parallel to axis should be avioded on guitars as it would split way too easily with impact on neck and top/back would split as well... On A style mandolin it is acceptable as the block is rather long in the direction of grain.
Another (though not conscious) advantage of the traditional orientation is that it is easier to steam out the neck without damage to rest of instruments - the crossgrain keeps the structure more stable during steaming (block with grain parallel with top would expand greatly and easily split the top and back. I've seen that!

These would be practical considerations that might outweigh the long-term integrity of neck joint issue. Perhaps these are the types of reasons behind the choice of those grain orientations. Compromises have to be made on many levels, often, when working with natural materials. In general, though the consequences of wood movement over time are difficult to predict perfectly, the parallel orientation is best for joint integrity, while the cross-orientation is best for reducing season splits. Thus plywood was invented, in part, to provide a material where splits are avoided.

[Bluetickhound]

Just got a steal on a beautifully figured 5/4 maple board... The grain (for the most part) runs diagonal. Reading previous posts I'm assuming this is called "rift-sawn"... Is it unsuitable for necks?



You can see some checking on the end grain but it only goes about 1/2" deep and will be cut off anyway.

[fscotte]

A picture is worth 1,000 words. To illustrate what I wrote in my last post, I went to google to find some images. Although I'm not a luthier, if I were to build a mandolin with a dovetail neck joint, I'd orient the block as illustrated below. I have very strong reasons for this having to do with the longevity of a quality build, in my opinion, due to the minuscule movements of wood over the decades, and based on many years of fine woodworking experience.

NOT LIKE THIS:


LIKE THESE:




As best I can understand from google images, that first image is from a kit someone sells - and the grain of the block runs counter to the grain of the neck, which in my opinion is poor engineering. The second image is Peter Coombe's, and the third is Troy Harris.

I've done it both ways, and honestly I feel more comfortable having the neck block grain run parallel as in the 2nd image. I've had the little wings break when fitting the dovetail when I was using a perpendicular grain direction. Not much wood there to withstand the tension during fitting

[Jim Hilburn]

You can use a piece of paper and some scissors to see what your neck grain would look like. If you lay out your neck profile like in 4 which I like to call bookmatched even though that's probably not correct then you can see how a 2 piece would look on the endgrain. I see it as completely acceptable. It should end up with all straight quartered looking grain lines on the back of the neck.

[Jim Hilburn]

This is my preferred end grain look. When bookmatched you get very nice straight grain lines on both sides of the neck and the curl usually lines up nicely too. I always use a thin ebony strip in the center.

- - - Updated - - -

However, not how Loars were done by the way.

[Jim Hilburn]

This neck was made like my last example. While the grain is angling away at the bottom, at the fingerboard surface it's nearly vertical or quartersawn if you like.

[Mark Gunter]

I'm assuming this is called "rift-sawn"

It really doesn't matter what you call it so long as it looks good, you make good use of it and you're happy with the results!

Since you mentioned it, I'll give new examples and write a few more words on what "rift cut" and "rift sawn" mean in the lumber industry at large. But please bear in mind, these are just simplified examples and explanations. Also, please bear in mind that I am no luthier. I do not know how any violin makers, C. F. Martin luthiers or Gibson luthiers might have chosen to use the same terms. This forum is frequented by a number of very knowledgeable and well-respected working luthiers who can answer that.

The most impactful thing about rift sawn lumber as an end product is that it has extremely straight grain! Both faces and both edges will look more consistent than with any other method of cutting wood! So why isn't all lumber rift sawn? It is the most wasteful and most expensive way of cutting lumber. Here is a very brief video that does a decent job of just barely introducing the subject:



There are good features of plain sawn and quarter sawn lumber. Quarter sawn lumber usually produces a very straight grain as well, but also in many species it also brings out features that are very beautiful. Figured woods really tend to look great quarter sawn. And plain sawn lumber has been beneficial to our species for time immemorial in building things. All sorts of things. And it produces the least amount of waste, and is the least expensive.

What would I call your maple? I'd call it a good score! I'd call it gorgeous!

Enjoy your score, I hope that some of what I've written in this thread makes sense and helps some folk to understand industry standards and such, but in the end the only technical details that will matter are the ones you skillfully put into your building. What you guys do is amazing.

AWI Standards define rift differently, and for ease of milling rift can be straight grain boards with the growth rings at greater angle through the cross sections of the board, as in this video dealing with the milling of oak logs:

[bpatrick]

I've cut my neck blocks at more of a slant so that the narrow section that connects the actual heel and scroll has long grain. This puts the actual dovetail area at an angle. Maybe the best of both worlds? From a grain/strength standpoint, this makes sense to me. However, lamination would add even more strength as long as the glue holds up over the very long term. Also, if a neck ever needs to be steamed off, it would seem that the lamination could be damaged.

I included some photos of my blocks and a photo of Lynn Dudenbostel's work. The photo of the blocks on the bandsaw are from an old website showing Lynn's process.

[Jim Hilburn]

The Frank Miller video is quite informative but has little to do with what we think of as quartersawn tops and backs used in carved archtop construction. More like rolltop desks. They specialize in quartered lumber, not tonewood.

[John Arnold]

I'm sorry, but the illustrations are wrong, and the video has serious errors. What is illustrated as rift sawn is not correct. That is radial sawn, which is the way instrument soundboards are cut so that all boards are vertical grain. Rift sawn lumber has grain that is between vertical and flat (approximately 45 degrees)....that is the only way that the grain can appear straight on all four sides of a board. Vertical grain boards show flat grain on the edges.
The first error in the video is when they show the center board from plain sawing to have cathedral grain. The center board has vertical grain. Cathedral grain occurs in the boards cut away from the center board. There are other errors in the video, but that much stupidity in one place just gives me a headache.

The reason the violin world uses quartered blocks for necks with resultant flat grain is simple. The block is turned on edge to make a neck, because the largest dimension is the depth of the neck, not the width. Flat grain is used to prevent splitting of the pegbox at the peg holes.
Similarly, Martin one-piece necks are made from a flat sawn 3X4 block, turned on edge to produce grain perpendicular to the fingerboard plane.

To answer the OP question, I would use 45 degree grain through the neck block to reduce splitting. and angle the grain direction up toward the scroll side so that there is less short grain in that area. I believe that is the way the old Gibsons were done.

[Mark Gunter]

The first error in the video is when they show the center board from plain sawing to have cathedral grain. The center board has vertical grain. Cathedral grain occurs in the boards cut away from the center board. There are other errors in the video, but that much stupidity in one place just gives me a headache.

John, your comment brought a chuckle and I empathize with your headache. That video is simplistic and has glaring errors in graphics, obviously I didn't spend much time searching for a great video. In post #21 I explained that the center plain sawn cuts result in quartered and rift grain at the sides of the boards (heartwood in the center). I think the video was sort of dummy way of saying that plain sawn boards generally show grain cathedrals, but when they make it appear that way on the center board it loses credibility.

Rifting a log by splitting quarters and billets is way more applicable to lutherie anyway. Also, though I've read and used AWI standards on architectural millwork and cabinetry I was unaware until last night on the standard they've set for what constitutes rift sawn lumber. What that means is that for over 20 years I've taught some incorrect details to at least a couple dozen apprentices in the furniture and millwork repair industry, basing my own understanding on texts and graphics used when I was learning these things 30 years ago. According to AWI standards, rift sawn has grain as you described, and is cut in the manner described by the Frank Miller video.

It seems that radial sawing and rift sawing are terms that are sometimes used interchangeably, evidence abounds in many places, and I was taught that way. I'm happy to defer to the AWI standards that say otherwise. As someone has mentioned above, this radial sawing pattern is more akin to splitting billets, and for the same reason I think, to get straight grain in a natural plane across the board.

Also, according to AWI standards, Oliver in post #18 was correct about the third graphic in the picture I posted way back there.

And a note to anyone following this discussion who is relatively new to woodworking: the +- 45* grain that John and others have mentioned in rift sawn lumber is not on the face of a board, they're referring to end grain at the ends of the board. Rift sawn yields a straight grain pattern on the face of a board.