Quartersawn Vs. Flatsawn: Guitar Bracing
This is an excerpt from “Roughing Out the Braces”
http://www.ericschaeferguitars.com/course/building-an-om-acoustic/
Transcript:
Now we are going to rough out our brace blanks from billets of spruce. Before we get started with that we just need to understand the difference between quarter sawn and flat sawn.
To get a better understanding of quarter sawn vs. flat sawn lets take a look at the source of the spruce.
First, look at the top of the diagram. The end grain pattern of quartersawn wood is nearly 90 degrees to the face of the board.
This nearly vertical grain orientation imparts the structural integrity that we need if the braces are glued with the quartersawn face up.
In contrast, look at the bottom of the diagram. The end grain pattern of flat sawn wood is nearly parallel or 0 degrees to the face of the board.
Braces glued with the flatsawn face up will have significantly less structural integrity.
This is why we glue our braces with the quartersawn face up.
If you are having a hard time determining which face is quartersawn, then you may have a riftsawn board.
Riftsawn boards are somewhere between quarter and flat sawn with an end grain pattern close to 45 degrees.
Don’t expect all your brace stock to be perfectly quartersawn along its length.
Boards with an end grain pattern as skewed as 60 degrees to the face are acceptable.
A good rule of thumb is: If you can’t determine which face is the quartersawn face, then the board is rift sawn and it should be tossed.
This is the quarter sawn face. As you can see the grain lines are very close together. That is because the grain lines are coming out at the camera.
This is the flat sawn face. This is because the grain lines are coming out at an angle. As you can see there are no tight grain lines.
On all of our braces we are going to have the quartersawn face standing up and the flat sawn faces on the sides.
