I usually write here with the guitarist or guitar-maker in mind or at the very least someone with in interest in woodworking. However, the other day I was explaining the concepts of “quarter-sawn” and “split billets” to a layman and there were a lot of things that I took for granted. I am going to try to explain those concepts here. First let me clarify a few definitions. When I want to use a piece of spruce I look at the fibre of the wood and the tree rings. There are many other considerations but in terms of structure that is it. The fibre or grain is what runs along the length of a tree and very often along the length of a piece of wood. A splinter in your finger is a short length of fibre. If you work along the grain (or against the grain) that is the dimension I am talking about. Tree rings are the lines that you see on the end grain of a board; circular but on a piece from a larger tree the sections of a circle can look straight. When I use spruce for tops or bracing and cedar for necks and braces I usually want wood that is cut perfectly along the fibre in the length and I want the tree rings to be sitting perpendicular to the plane of the neck or the plane of the top. In the photos of the bookshelf below you can see circular tree rings on one board and perpendicular tree rings on the other.

bookshelf1

bookshelf2

The question is how do I get wood which is cut along the grain and has the tree rings in the configuration I am looking for? The only way to cut your wood along the grain is to split it and then use that surface as a reference. You have to correct it a bit because it will neither be flat nor smooth. As for perpendicular tree rings it is just a question of cutting the wood so that the width of the board ends up being a radius of the circular section of the tree. The way to do that is to rift-saw your tree. If you quarter-saw a tree you will end up with some boards that are a perfect radius and the rest will be close. This is why many folks refer to perpendicular tree rings in wood as quarter-sawn wood even though this is “incorrect”. Rift-sawn actually gets misused as well probably because quarter-sawn is taking its place. The problem is that the words refer to the process but we want to talk about the result so we use the best word we have. Flat-sawn gives you wood like you see in the bookshelf photos above, some good, some not so good but there is no waste. Most applications that use wood will use wood with any ring orientation, not so for instrument-making. A quarter-sawn top is stiffer across the grain and so can be worked thinner and lighter which is desirable for sound production. Quarter-sawn wood will also react less to humidity changes and so will lose less volume over the years across the width (less likely to crack) and will warp less. Wood cut along the fibre of the tree is stronger and stiffer along the grain and theoretically will transmit sound better. It is also easier to carve when you scallop the braces or carve the shape of the neck. We are always looking for maximum responsiveness, maximum strength and minimum mass. (This is a massive generalization but useful here.)

guitar top

Above is a photo of a guitar top’s edge which shows the tree rings perpendicular to the width of the top so they are vertical to the plane of the top. I am including a video which shows a board which I split in order to see how the fibre runs and there you can see the tree rings portraying how I will have to modify the cut to get “quarter-sawn” braces out of it. In the photo below of the thicker brace you can see the final result that I am going for in cutting braces. I want the rings to be tall and parallel to the height while for a top I want the same “vertical” orientation and parallel to the wide dimension.

In conclusion, if you can split your own wood and examine the rings you will always have perfectly cut wood. If you are examining the wood on a completed instrument there are indications that a top has perpendicular tree rings (the appearance medullar rays) and that a top was cut following the split line (the reflections on a bookmatched top). You can use these tricks when choosing tonewood which is almost always sold with cut, not split surfaces.

I had to take a guitar to Alicante yesterday and the guitarist and I met at the workshop of F.J. Riquelme. It is always a pleasure to meet someone who is passionate about the guitar and I had lunch and conversation with Riquelme (in the photo) afterwards by the sea. He studied for a time with Dominique de la Rue so I expect great things from him soon. See his work at Galerie de Luthiers.

We all know what bearclaw looks like whether we call it maschiato, hazelfichte or rizado. However, I had never examined the flat-sawn surface of a really good bearclaw board. My last post showed some of the spruce that I used to make braces and here is another one. You can see the typical surface of the bear claw along the quarter but in the next picture you see what the flat-sawn surface looks like. Pretty cool, eh?

Some think that bearclaw is very desirable for guitar tops while others feel that anything which interrupts the straight, parallel grain cannot possibly be good for sound transmission. I have seen very flexible bearclaw and very stiff, both along the grain and transversely. I have made some excellent guitars with bearclaw so while I don’t think it is any better I do think that a well-chosen piece can make a great instrument. The main attraction of bearclaw of course is its beauty.

I don’t think many makers are using bearclaw for bracing and I normally wouldn’t either but I did put aside one set this time. I am going to dig through my bearclaw tops and find a particularily intense one and brace it with this set of braces, just for fun. I don’t think I will see any great difference especially since I selected the braces the same way I always do: split them and test them for longitudinal strength.

You don’t need perfectly quartered stock for making braces nor do you need the raw billet to be cut perfectly along the grain the way this is. However, if you want maximum strength and stability per gram then you do need to split it and follow the grain and then cut each brace on the quarter. Of course this is easier and creates less waste if the billet looks like these. I always split my stock for braces as well as my stock for necks. It introduces some repeatability which is pretty hard to come by in guitar-making. These pieces made some nice stiff fan braces and the process was quite fast. However, I split a few more billets at the same time and some of those weren’t quite so perfect. In the end I spent considerably more time on the off quarter pieces especially the ones that split diagonally through the length. I used three different saw setups and three different planer setups through this whole process. One of those billets had a little surprise for me but I will talk about that in the next post.

So I now have hundreds of triangular-profiled sticks; some stiff and some not so stiff and some lightweight and some a bit heavier. I will use the stiffer ones for the centre fan braces and the lightweight ones on flamenco guitars. Because of the splitting beforehand every one of them is as strong as it can be and when I scallop the ends after they are glued to the soundboard they will carve very nicely.

Indian rosewood is a great wood to make guitars with. So far it is not scarce or controlled and it contributes to making a great-sounding guitar.  It is also very stable, in part because you can usually find it cut on the quarter. The widespread preference for Brazillian rosewood is due to a few factors that can be a bit contradictory. Buyers love Brazillian because it is scarce and expensive and because it can be very beautiful. Makers love Brazillian because it is nice to work with. A plane and a scraper leave a lovely surface, the smell is heavenly and it has a nice sonorous ring to it when you tap it.  However, beautiful to a woodworker and beautiful to a buyer is not always the same thing. We love well-quartered wood no matter what the species. The shine of the medullar rays and the even grain is the perfection we look for. I have used great pieces of Brazillian like that and had clients say, “No, that’s Indian rosewood”. These are the clients that want crazy grain patterns, various colours in the same piece and spider webbing that to them are the indications that it really is Brazillian. Crazy grain makes for a greater likelihood of cracks, different colours often indicates a flat-sawn piece while scarcity means that it is expensive and its commerce severely restricted. So why use it? Especially if many of us have found that it really doesn’t make your guitar sound any better. Furthermore, why spend the extra money on it if the best pieces are going to be confused with Indian rosewood making it hard to pass on the extra cost to the client? Just to illustrate the confusion here are 4 guitars under construction: 2 of them are being made with a south american rosewood and the other 2 are being made with Indian rosewood. Can you tell which is which? Letter A, Letter B, Letter C, Letter D.

Letter C

Letter D

Letter B

Letter A