Bat shaving is a bat modification that decreases the thickness of a bat’s inner cylinder. The end cap is removed and a digital precision lathe “shaves” the inside of the barrel. The decrease in alloy or composite material allows the barrel to flex more at the point of impact, which translates into higher batted ball speed. The increased ball speed can add 40-50 feet with shaving alone, add the swing of the bat before shaving and that number goes up even more.
There are many people who open a bat and shave the inside with a drill (or drum sander). Sharpening will create “hot spots” and “dead spots” throughout the shaving cylinder. A hot spot is where the spot shaves off too much and the barrel will flex more. This sounds good because we want more flexibility for more distance, right? Not exactly, the hot spot will cause a weak spot in the barrel and significantly increase the chance of it breaking. There are default widths for the bat shave, which test the limits of the bat in strength and durability. Sanding beyond these limits will cause the bat to break prematurely. Dead spots are just the opposite of hot spots; they cause the bat to flex less, which causes a decrease in distance. A bat fresh from the factory will often have inconsistencies of 5 to 10 thousandths of an inch along the barrel. Precision turning your bat will actually create the most accurate wall available. A constant wall allows the bat to have the same flex around the bat for more distance and better durability (remember, a shaved bat is less durable). The main point is that sanding the inside of a barrel will never be consistent or precise, only a lathe can do that.
Most people who shave on eBay (and even some on the Internet) use a drill polisher (drum sander); That’s why you’ll see cheap prices on eBay for bat shaving services. The lathe should have a digital readout to decrease the chance of inaccuracies. One pass through the lathe is not as accurate as removing material in 2 or 3 passes. It would be like using coarse grit sandpaper instead of fine grit sandpaper. Fine grit will take longer but produces a better product. When the bat is removed from the lathe, it will have lost 1 to 2 ounces of material, depending on the manufacturer of the bat (different bats have different specifications). That weight needs to be put back on the bat in the handle and end cap; an additional amount can usually be placed in the cap for a final charge. If you didn’t know, all manufacturers create their kegs to weigh the same. They put metal weight in the handle and additional resin in the end cap to weigh the bat down between 26 and 30 ounces. After the weight is added back, the end cap is reattached with the correct glue; substandard glue could cause the end cap to separate and even come off.
