First, what's it mean to "rip"? It just means to cut a long board lengthwise. For example, when building a door or window frame, you invariably need to shave off a half an inch or so from the length of the board. There are even times I have cut a two-by-eight in half lengthwise to produce a couple of makeshift two-by-fours. If you've tried to do this with a circular saw, or God forbid with a handsaw, you know it's impossible to cut a straight line. Sometimes, it's impossible to cut it at all.
1. Loosen the GateThe gate is the metal guide that runs parallel to the saw blade. Don't remove the gate. Just loosen it so it slides easily.
2. Mark Your BoardFor the purpose of illustration, let's say you're cutting the two-by-eight in half lengthwise. Using a tape measure, mark the exact midpoint of the width of the board with a pencil. You don't need to draw a line all the way down the length of the board. That's one of the nice things about table saws. You can adjust the gate to whatever measurement you want, and you can trust that the saw will maintain this measurement all the way through. Yes, it really works.
3. Set the GateSet the marked end of the board on the top of the table saw. Adjust the wood so that the teeth of the saw are touching your pencil mark. Then, move the wood slightly left so that you will not be cutting exactly on the mark. You want to "preserve" the mark. Table saws chew up so much wood that it will throw off your measurement by at least 1/8" if you don't "preserve" your mark. Finally, make sure the gate is snug against the side of your wood and then snap the gate back into place tight.
4. Make the Board LevelIf you're lucky enough to have a table saw set into an actual table, you can skip this step. But if you have a stand-alone saw, you need to have a surface on both sides of the table saw that is level with the top of the saw. It's not so critical if you're cutting a board less than four feet long. But for longer boards, the board will see-saw as you feed it through. I usually put together a makeshift surface made out of stacked up blocks of wood with plywood on top.
5. Run the Wood Through the Table SawPut on your safety glasses, make sure the saw's safety guard is down, and flip on the power switch. I find gloves to be more of a hindrance than a help, but this is your choice.
Push the wood through at a slow but steady rate, keeping it pressed lightly against the gate. If you slow down or stop, you will notch big grooves out of your wood, destroying your nice straight line. You must keep the wood moving. When the wood is about halfway through, concentrate more on the wood coming out of the saw rather than on the feed end. I even move around to this end and switch from pushing the wood to pulling the wood. It's a difficult maneuver, requiring some fancy footwork.
One alternative to this ballet move is to always remain on the "feed" end and always keep pushing. The downside is that as you approach the end of your cut, your hands get closer and closer to the saw blade. Now what? A "push stick" is needed. A push stick is an expendable stick around two feet long and one-by-one square. With this push stick you can force the board through that last foot or so. The push stick will go where you don't want your hands to go!