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If you’ve ever noticed that the edge of your board gets splintered while you’re cutting, you’re dealing with one of the most common problems for woodworkers: tearout. Tearout can be caused by using the wrong type of saw blade, a dull blade, or from improperly positioned lumber. But sometimes, you can do all these things correctly and still have a splinter problem. Sanding can help if your splintering is minimal, but here are some other methods to help prevent splintering from happening.
How to prevent tearout with a backer board
One of the most common ways to prevent splintering when using a chop saw or miter saw is to use a backer board. This is a simple way to support the grain of your lumber from the back side while cutting. Since the blade on a saw used for cross-cutting spins 90 degrees to the direction of the grain, the blade can tend to pull splinters out on the back side of your board. Place a scrap of wood against the fence of the saw—the part that you push your lumber up against to make your cut—before you position your board. Then, place your board against the scrap and make your cut through both the board and your scrap. The backer board will support the lumber you’re cutting, reducing tearout.
You can also use a backer board on a table saw, but you’ll need a board that’s at least as wide as the cut you’re making for it to work, making this method impractical in some circumstances. To use this method, place the board you’re cutting on top of another piece of lumber before cutting on the table saw. This can help some with tearout on the bottom side of your piece.
Preventing tearout with tape
Tape is another good fix for preventing tearout. If you’re cutting on a table saw, using a strip of masking tape or blue tape on the top side of your board above where the blade is positioned and cutting with the good side down can help prevent tearout. On a circular saw, you can use tape on the bottom side of your board, cutting with the good side up. Be aware that cutting through tape will likely dull your saw blade more quickly, but it might be worth it, depending on how precise you need the edges of your cut to be.
Preventing tearout with scoring
To keep tearout from happening, one helpful method is to score the board along your cut line before cutting. You can do this with a utility knife, a scoring tool, or any blade you have handy by making a groove with your tool using a straight edge along your cut line before making your cut. Essentially what this method does is pre-cut the surface of your board without teeth, making it less likely for the saw blade to catch on splinters as it spins and the teeth exit the board.
Reducing tearout using a router
If tearout prevention methods don’t work or are impractical, you can make a cut that’s an eighth to a quarter inch outside your cut line and then attach a straight board along your cut line and trim the remaining material with a flush trim bit in a router. Since the router blade usually spins perpendicular to your board, a sharp flush trim bit should produce very little tearout. For curved or irregular cuts, you can make a template that’s the exact size and shape of your cut, then use the router to trim your piece to the shape you want using the same method. This is also a good way to make multiple pieces the same size and shape.
Preventing tearout when drilling holes
If you’re using a drill press, clamping a scrap piece of wood onto the foot of your press before drilling can give the bottom of your board’s grain support as the drill bit exits the board. You can reduce splintering using this method with a hand-held drill, too, by clamping a scrap to the back side of your mark, making sure the clamp is clear of the hole, and drilling with the scrap in place. You can also drill a shallow hole on the opposite side of your board and then drill through from the top, reducing the exposed surface grain that needs to be drilled through.
Combining tearout prevention methods
There’s no rule that says you can’t use tape and a backer board and scoring at the same time. Combining methods, especially if you’re trying to make a very clean, precise cut, will decrease tearout even more. You should also make sure your blade is sharp and that you’re using the appropriate one for the job you’re doing. If you’re making a cross cut, make sure you have a cross-cut blade on your saw, and if you’re making a rip cut, going with the grain, make sure you have a blade that’s designed for that cut on your saw.