Also, the knife’s arced shape closely mirrors the blade’s curve to minimize the gap between the two, preventing any potential board wander before the board’s edge reaches the knife.Īll tablesaws sold in the U.S. Because its top end can be set just below the blade’s top-dead-center, it doesn’t need to be removed to make grooves and other non-through cuts. The main difference between a riving knife and a splitter (or spreader) is that a riving knife is mounted in such a way that it rises, falls, and tilts with the blade (Photo C). Each of these plates sits aft of the blade and, when properly aligned, as shown in Photo B, keeps the workpiece against the fence to deny it access to the rising rear saw teeth. When it comes to preventing kickback, the best tool for the job is either a riving knife or a splitter. Uh oh.įor a blow-by-blow look at kickback in action, see pages 34 and 35.
The worst-case scenario is when the board suddenly disappears and your hand continues its forward motion into the blade. The other kickback scenario is when internal stresses in the wood cause the kerf to close onto the rising rear teeth, which also throws the board. The teeth then carry the board up onto the spinning blade, launching it backwards. This causes the leading end of the board to wander over against the rising teeth at the rear of the blade. During typical ripping, your pushstick applies forward pressure to the rear right-hand corner next to the fence, while the blade entering the work near the diagonally opposing corner applies rearward pressure. But here’s what is going on:Īs shown in Figure 1, applying pressure to opposing corners of a board causes it to rotate. Unfortunately, few woodworkers understand what causes kickback because it happens so fast. This has probably happened to anyone who has worked at a tablesaw for very long without a splitter. The more common–and more dangerous–form of kickback is when the entire workpiece is thrown upward and backward at a fierce speed toward you. To avoid injury in this case, never stand directly behind a board being ripped, which is standard practice anyway. This usually only happens if your pushstick slips off the stock. One is when a ripped strip–typically a narrow one–ejects rearward like an arrow from between the blade and the fence. When working at the tablesaw, there are two primary ways that a piece of wood can be thrown back at you. Senior editor Paul Anthony is the author of The Complete Illustrated Guide to Tablesaws (Taunton Press). If you use a tablesaw, this is stuff you absolutely need to know. Here, we’ll take a close look at why kickback happens and how you can prevent it by adjusting your tablesaw properly and outfitting it with an appropriate commercial or shop-made anti-kickback accessory. By understanding the mechanics, you can counter the forces involved and maneuver your stock with assured safety. Kickback is not a risk you have to learn to accept when using a tablesaw, since you can easily prevent this kind of misbehavior. If it’s lashing out at you, it’s only because you’re not using it properly. Whatever the case, don’t blame your saw for being temperamental. Ouch! Or perhaps the wooden projectile just crashed through a shop wall.
Worse yet, maybe you were carelessly feeding with your bare hand instead of using a pushstick, and the escaping board suddenly directs your fingers into the blade. Ever been sucker-punched by your tablesaw? You may know what I’m talking about: You’re happily sawing along when–BAM!–in a flash, the board you were ripping flies back and slams you in the gut.
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