Louisville Slugger Makes Prime Bat 30% Harder By Dipping Into 1902 Company Patent

Image credit: Ronald Acuña Jr. (Photo courtesy of Louisville Slugger)

Everything about the completely revamped Louisville Slugger Prime wood bat line launching April 17 focuses on making the bat harder. To get there, it required the team to reimagine the manufacturing process, borrow finishing concepts from the guitar industry and dip back into a 1902 patent from one of the brand’s founders. 

There’s a lot that’s new in the fresh iteration of the Louisville Slugger Prime line to get the bats 30% harder and allow the 140-year-old brand to more than double the warranty from 30 days to an industry-leading 75 days. It all starts with a trip back into company history. 

Bobby Hillerich, a fifth-generation bat maker and vice president of manufacturing and product development, is a great-grandson of Bud Hillerich, who created the first-ever Slugger bat for professional Louisville Eclipse player Pete Browning in his father’s woodworking shop. Bobby Hillerich was researching published studies on wood surface hardening techniques when he saw a Penn State University study reference a 1902 patent from his great-grandfather regarding hickory wood spun on a lathe. 

“There is a combination of pressure and heat that is getting us the surface tension that we want,” Bobby Hillerich tells Baseball America. “We’ve updated it with new techniques and pressures.” 

The entire Louisville Slugger manufacturing process received an update. For the new Prime line, made with both maple and birch, the hardening is more than just the pressure and heat. It also comes from optimizing the brand’s vacuum drying system. Previously, wood could sit up to three weeks before going from green to vacuum driers at the Pennsylvania factory, but the cells started hardening while air drying, not allowing the vacuum to compress them. Louisville Slugger now vacuum dries the wood the same week they are processed from the log, all while keeping them stored at 70 degrees to increase stability. 

Once the billets get shipped to Louisville and turned and shaped into a bat, they receive a completely new finish. In search for a finish that wouldn’t take four days to cure, Bobby Hillerich and his team flew to San Diego to check out a process Taylor Guitar was using on their instruments. “We sprayed it on a bat and went and hit it on a steel post,” he says about the visit. “It was fantastic.” 

From there, Slugger met with Taylor Guitar’s engineer and the finish supplier, and the result was a finish developed for bats that can cure in a UV line in 13 seconds. “If we are rushing a bat out for a player,” Bobby Hillerich says, “13 seconds in the UV line and its done.”

The combination of selecting only the hardest woods, the vacuum drying, pressure and heat when turning and a new finish adds up to a bat 30% harder than the previous version. “This is our hardest wood product we have ever made,” Joe Cmelik, senior product line manager, tells Baseball America. “We really went back to the basics, broke down where we were at and where we wanted to be. We see it as a new product.” 

The game’s top players have tested the bat for the last year and Cmelik calls the feedback “overwhelmingly positive,” with players commenting on it without prompting. “They notice this bat is a lot harder,” he says. “They notice it in sound, notice it in feel, they are not seeing ball marks.” 

The harder the bat, the more energy transfer to the ball, ideally increasing exit-speed velocity. “We are always looking for a couple extra feet,” Bobby Hillerich says. The results panned out during the 2023 MLB season, with Ronald Acuna Jr., Cody Bellinger and Kyle Schwarber all having outstanding seasons using the updated technology.

Now Slugger brings that technology to scale with the April 17 retail launch of the entire Prime line. Cmelik expects the RA13 Ronald Acuna Jr. player model and the C271 to remain the most popular bats in the lineup, and Louisville Slugger also plans limited editions and different colorways throughout the year. The Prime wood line has proven sought after at retail by high-level travel players, but also by college players in wood bat leagues. 

No matter the Prime style, every model has received the complete update, but the fifth-generation bat maker still gets drawn to the natural wood finish. It’s in his blood, after all. “I like,” Bobby Hillerich says, “to see everything inside that piece of wood.” 

Tim Newcomb covers gear and business for Baseball America.