Vertical slots can be cut into wood with a table saw. They can be functional, such as part of a mortise and tenon joint or part of a sound system where sound and air pass through, or they can be for aesthetics. Table saws are the best option for cutting slots into any board because the fence guides and aligns the slot perfectly. Vertical slots are always cut parallel to the grain of the wood.
Lower the blade down below the surface of the table saw. No part of the blade should be visible above the surface.
Measure the board where you wish to cut a slot. Set the table saw fence at that measurement. Make two marks on the wood with a pencil, one where the slot will begin and one where the slot will stop.
Place the wood blank on top of the saw where the blade emerges; cover the slot where the blade comes up with the wood blank. The blade should be directly under the place where you want the slot.
Turn on the saw. Crouch down in front of the saw. Hold the wood down firmly to the saw with your left hand. Reach over and begin cranking the wheel to raise the blade. As the blade begins to cut up through the wood, continue holding it down firmly with your other hand until the tip of the blade emerges out through the top of the wood approximately 1 inch high.
Stand up and push the wood forward until the saw blade touches the pencil mark you made where the slot will stop. Reach down and turn off the saw. When it slows down, lower the blade beneath the table again.
Slide the fence over according to how wide you want the slot. If the slot is to be 3/4 inch, then move the fence over 3/4 inch to the right. Push the wood over against the fence.
Repeat steps 3 and 4 to cut the slot. Remove the board from the saw. Finish the slot by inserting a hand saw into the slot and cutting both sides of the slot until they touch the pencil lines. Use a hammer and wood chisel to cut the inside of the slot free from the ends of the board.
Use a cabinetmaker's crosscut blade for best results, but any blade will work.
Always wear safety glasses. Only experienced woodworkers should attempt operations such as slot cutting.