A Misunderstood Heart
Here’s a lie I heard once at a lumberyard: When picking out boards, you should always choose ones that have the heart – or pith – in them because that is the strongest part of the tree. Those boards will be the strongest.
Here’s a second lie I heard at another lumberyard: Never pick boards with the heart in them because the board will surely split, ruining your project.
The truth is something else, of course.
When buying boards, particularly boards that will be ripped down, I always look for boards with the heart included. Not because it’s the strongest part of the tree. That’s malarky. The pith is the the twiggy center of the tree and will indeed split on you almost every time.
So why do I look for the heart? Two reasons.
1. Many woodworkers pass over these boards because they’ve been told to avoid them.
2. The best pure quartersawn material is always right next to the heart.
That quartersawn stock is the most stable cut. It is the straightest. And it is great for rails, stiles and other parts of your project that need dead-straight grain.
So I gobble up these pithy boards and rip the boards to the right and left of the pith. This gives me scads of stable lumber without having to pay a premium for quartersawn stock (which is usually rift and not purely quartersawn).
— Christopher Schwarz
P.S. Side note on the pith. Japanese carpenters actually do choose posts for temples that include the pith. How to they avoid the splitting? They saw a kerf into the post that breaches the heart and then pack the kerf with softwood, according to a book I read years ago on Japanese carpentry. Pretty clever.
Want to learn more about your material and how it interacts with your tools? Get Roy Underhill’s “Woodwright’s Guide,” my favorite book from my favorite woodworker. It’s available at ShopWoodworking.com here.