Over the course of one season, thousands of pieces of wood are sent from Pennsylvania and New York to Old Hickory Bat Company, a small bat-making operation just north of Nashville. Out of those billets (chunks of wood), no more than one-fifth will become pro-grade baseball bats wielded by the likes of Colorado hitters Charlie Blackmon, Trevor Story, Mark Reynolds, and Nolan Arenado—all of whom get their bats from Old Hickory.

Whereas the players on the field come from all over, the wood that makes up the bats almost certainly originated in a comparatively small stretch of northern Pennsylvania/southern New York forests. There, says Travis Copley of Old Hickory, the growing season is better than anywhere else in the country for maple, birch, and ash trees—the only types of wood approved for bats in the MLB.

Billets are cut from those three species and packed into pallets, which are then loaded onto semi-trucks and taken to one of the 32 companies who are licensed to make professional baseball bats. According to Copley, the majority of the wood, probably 75–80 percent, is maple—the hardest and most popular species of wood that players use in the majors. This time of year is busy, and Old Hickory receives about 2–3 shipments of 250–300 billets every 10 days.

But only the best billets go pro. Much like the players who use them, the wood and the resulting bats are thoroughly examined. Woodworkers check the billets several times over to ensure each bat is “free of defects,” as Copley puts it. “That means no cosmetic blemishes, ingrown bark, mineral streaks, things like that.” They even look at the color of the wood.

None of that, though, is more important than the grain slope. Major League bats have only the straightest possible grains. If a bat has good grain, but iffy cosmetics, it might end up in the minor leagues or even at a Sunday beer league. They throw the rest into a blend pile. “Cage bats,” Copley says. “We sell them at a bit of a discounted price so that when they break—like all wood bats do—it hurts a bit less.”

Some places have switched to an automated sanding process, but not Old Hickory. This time of year, the hands Old Hickory’s sanders are cracked, blistered, and even bloody. But hand-sanding allows for an attention to detail that is essential for quality control, Copley says.

With only 12 people, Old Hickory made more than 50,000 bats last year. This year, the Rockies are one of its biggest customers. But each bat must meet personal specifications down to where the logo, initials, and number of a player are engraved. Players request all of these specifications prior to opening day. To fans of Harry Potter, it’s like a complete reversal from wand-maker Ollivander’s “The wand chooses the wizard” theory.

The pride in their work is hard to miss.

“For us, it’s probably the second-greatest job in the world,” Copley says. “We still get to be around the game and interact with the players, and to a certain degree, we did make the big leagues. It’s something that we spend eight hours a day doing and it’s our handiwork that we get to see on TV.”