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There was an interesting thread on MyLesPaul today about quartersawn wood…

There are a number of views on how much it matters that guitar necks be quartersawn. Personally I would use quartered or flatsawn only, nothing with distinctly angled grain. However some say it doesn’t matter, as long as it’s stable.

It came up in conversation, however, that often saw marks or end grain sealer at the lumber yard covers up the end grain of the wood, making it difficult to identify the grain direction while you are there. So I thought I would share this.

This is widely known by acoustic builders, but I think electric guitar builders tend to pay less attention to the structure of wood to some degree. I wanted this to be posted here so that it gets archived along with the other tips and techniques…that way it’s here for anyone just getting started in guitar building to learn about.

So here it is, a piece of basic lutherie knowledge that everyone should be aware of: How to identify quartersawn wood, without looking at the endgrain (or, a brief lesson in the anatomy of wood).

It’s actually very simple. I must note that you’ll rarely come across wood that is perfectly quartered so as to display this in a regular lumber yard (unless they have wood marked as quartered, or a section for instrument woods), but if you bring a finger plane with you, you can find out the grain direction of rough sawn lumber quickly and easily by looking for this characteristic. In addition, in the opinion of many, this should be the standard by which you assess whether wood is considered quartersawn for the purposes of lutherie.

In many woods, medullary ray is visible in perfectly quartered blocks. It is visible on the face of the wood that is perpendicular to the vertical grain. However, when the wood is off quarter by more than about 10 degrees, the ray disappears. So it is only visible in perfectly quartered wood. The ray is visible running sideways across the grain (at a 90 degree angle to the normal grain direction). Below is an example of medullary ray, here seen in a piece of African Mahogany:


However, here is a piece from the same block of mahogany, but this piece is slightly off quarter. Notice that the medullary ray is not visible in this piece. This means it is not perfectly quartersawn.


So, there you have it – the easy way to tell exactly which way the grain is running, without looking at the end grain. If you plane on the edge of a square block and the ray becomes visible, it’s rift sawn at about 45 degrees. If the ray is visible on the wide face, it’s quartersawn. If it’s visible on the narrow face, it’s flat sawn.