June 6, 2003
"In today's newsletter, we compare our product to various types of wood."
OK, so Sammy used a bat with a rough hole hewn into it, and filled it with a bunch of stuff. He'll be suspended, probably for about 10 days, and he's already apologized. My personal take on the specific incident is that he didn't know it was corked; he didn't seem fazed or worried about the shards left on the field, unlike others who have shattered adulterated bats and worried more about gathering the evidence than getting to first base. Doesn't really matter in the end. The annoying thing is how much airtime the whole issue's getting, and how often Will Carroll's been bumped from Outside the Lines so people can moralize and speculate.
Dr. Adair's phone probably started ringing within moments of the splinters flying, and writers and editors everywhere have been editing out important qualifiers to his explanations in the name of saving space. You know, qualifiers like "assuming bat speed remains constant." A lot of people have scrambled back to their high school and college textbooks to come up with the basic formulae for momentum, and all sorts of different experts are out there talking about the actual effectiveness of corking. The opinions range from "mildly helpful" to "mildly counterproductive," and each opinion that I've seen has had a whole bunch of implicit assumptions in it, ranging from "bat speed remains constant" to the less obvious "compromise of the wood will not result in more energy absorption by the bat."
As a woodworker, I'm also aware of the "the person who corked the bat has a clue about how to do so properly" assumption. That, by the way, is probably the biggest assumption of all. My workshop is currently filled with materials from my house because of our home remodel, otherwise, this week's column would have consisted of a step-by-step guide to corking a bat. Which would have involved no cork. I'm not an expert on corking bats, but I do know a bunch of ways that wood joinery can go horribly wrong.
Instead, I wanted to speak with someone who might provide a little different angle on the mechanics and effectiveness of corking a bat. When talking about aluminum bats in the past (and there's more interesting stuff going on in slow-pitch softball bats, balls, politics, and intrigue than in most soap operas), I've spoken to people in materials science departments at various universities, as well as the late, great Ray DeMarini. But for wooden bats, and the non-theoretical, real world constraints and realities of dealing with wood, I called Stephen Quarles, the Wood Durability Advisor at the University of California Forest Products Laboratory.
"The players could just use a lighter bat," said Quarles. "The advantage is in having a lighter bat." Quarles has a great web page on wooden bats, specifically ash vs. maple. "A good hitter can do just as well with either ash or maple; either is good enough. Anyway, average numbers about density don't mean much for individual bats anyway; there's a lot of variation even in the same species." Quarles' web site explains the importance of density variation in different species--another instance where "average" isn't informative enough. Go to the site to check it out. I'll wait...
...Welcome back. Ash and maple are fairly similar woods. The challenge in making a good bat is making one that's light enough to swing at max velocity, while having it strong enough to stand up to the forces generated during a swing and contact. A 33-inch bat that weighs 32 ounces in white ash would weigh about eight ounces if made out of balsa wood, and about 58 ounces if made of lignum vitae (ironwood).
The ability to transfer energy from the hitter to the ball is related to the density of the wood of the bat, and the flexibility of the bat. There are other factors, and since wood is a natural substance, there's going to be a lot of variation. Most species of pine are around 26-30 lbs./cubic foot; it's a soft wood, and it dents easily. You can put a permanent mark in it with mild pressure from your thumbnail. If a fastball were to hit a pine bat, it'd leave an indentation (at the least) in the bat, and a lot of energy of the interaction would be lost in the creation of that deformity--less energy would be transferred to the ball, so the ball wouldn't travel as far.
The advantage of corking is that you can reduce bat weight without giving up density. What are the densities of the commonly used woods in baseball bats? Here are the densities and hardness of the wood types typically used for wooden bats, and some other common uses for those species:
Species Density Hardness Other common uses (lbs/cubic ft) (Janka scale*) Ash (White) 42 1320 Tool handles Bentwood furniture Hickory 46 1820 Chairs Bentwood furniture Maple (Hard) 46 1450 Musical instruments Floors, veneers
*The Janka scale is a relative measure of hardness, based on the force necessary to embed a .444" diameter ball bearing halfway into a plank of the species being tested. For reference, yellow pine is about 690, red oak about 1290, cherry about 950. Density and usage data from The Complete Manual of Woodworking, by Jackson, Day, and Jennings.
There are a large number of other species of wood with comparable densities that haven't yet been tried as MLB bat stock, such as African Padauk, which is hard and light, but may not be flexible enough to make a good, springy bat. According to Quarles, "it's not just whether or not the density, hardness, and flexibility is right. Some woods don't dry evenly, and can be prone to checking, which would make it difficult to use for baseball bats." 'Checking' is splitting of the wood, particularly toward the ends, that occurs during drying.
Still, given the potential gain for a hitter, if I were making even the major league minimum, I would think an off-season visit to a woodworking group and a couple hundred bucks investment in various types of stock would be worth the risk. The cost difference between a bat made out of Padauk and a bat made out of maple really wouldn't be all that great, and if it can get you 2% more velocity off the bat, that might be the difference between a multi-year deal that sets you up for life and running the produce department at Giant Eagle.
After all, gaining an advantage by going against the rules is called cheating. Gaining an advantage by working around the rules to an area not previously considered by the rulemakers is innovation. Pitchers are mildly amused by cheating along the lines of what Sammy did--they know that if he gets all of a ball, it's going out. The marginal gain of corking is probably negligible at best, so why worry about it? But that innovation stuff--that's potentially dangerous to ERAs.