Before cutting up the chunk of cherry that I'm using for the horned smoothing plane, I consulted Philip Edwards of Philly Planes about grain orientation.
I had read that it's best to put the sapwood on the sole and the heartwood on top, but I wanted an expert's opinion.
Philly confirmed that he orients his planes this way, although he has seen antiques that were made heart-side-down and which seem to work fine.
First, the best wood is quartersawn. I did not use the correct section of the log in the photos (I used the flatsawn portion), so my plane will move across the width. When looking at the end of a plane (the heel or toe), the grain should be horizontal, not vertical. With seasonal movement, it's okay for the plane to get taller or shorter, but thinner in width can be a problem because the blade can become locked into the body of the plane. There may be other reasons for running the grain horizontally, but this is the one I know.*
In order to get the optimal grain orientation for my plane, the blank had to be sawn from the cherry at an angle.
I removed adjacent corners with an axe to create 90º angles, and cleaned up the faces with scrub and smoothing planes.
After that—just to be sure the blank was dead-on square—I used my power jointer and planer.
*A reader contacted me to let me know that this paragraph is incorrect—I did not say that your wood should be quartersawn in order to minimize seasonal movement (I've since added that bit). But just to avoid any misinformation, please have a look at the Old Street Tool site (formerly Clark & Williams) where they explain grain direction.