Routers are one of the most versatile tools in the shop. They can do a variety of tasks, including putting edge profiling on, like in moldings, they can create different types of joinery by removing material and creating slots for different shapes, and they can even cut out templates.
To give you an idea of the different things a router can do, take a quick look at these router bits and they'll give you a sense of what I'm talking about. For example, most of these bits at the top here, are used for creating edge profiles. You can see, there's a variety of different shapes. Some carve out a curve into the wood, called a cove. Some do a round-over. Some will create custom shapes. There's a Roman ogee. There's a whole category, also, of joinery cutting bits. The most common of which is a straight cutting bit, like this, which makes a straight slot. But, you'll also see bits that create wedge shaped slots, or dove tails. There's a whole variety of other ones, as well. If you look at the router bits, you get a sense of the shape that they make.
Router bits come in two different sizes, and this is important to understand. It will help you pick router bits, and also determine what kind of router to get. If we look at, for example, these two bits here. These are essentially the same, two bits that do the same function, they both cut out a three quarter inch slot, they're three quarter inches in diameter. But you can see on the bottom, they have two different sized shanks. I want to draw your attention to this, because these are the two most common sized shanks, the quarter inch and the half inch. Most routers can accommodate both sized shanks in their collets, simply by changing out the collet. So, we have two different sized collets. The collet is what holds the bit into the router. You can either use the one that hold the quarter inch bit, or you can use the one that hold the half inch bit. Either way, they both screw into the router at the base, and you're good to go.
Let's look at the routers, themselves. Routers have a lot of different controls on them to help make them operate smoothly and safely. I've got two different models of routers out here, to show you. One is called a plunge router. It's basic function is, if you need to start routing in the middle of a piece of wood, you can plunge down in, like a drill press, do your routing, and then plunge back out. So, it's a safe way to plunge down into the wood. The other kind of router that you'll see is a stationary router. A stationary router is the same thing as a plunge router, but it doesn't plunge. So, you put the bit in, and you'll either be working along an edge, so you can come into the edge safely and route away, or you'll come in from the end of the wood and go in, and come out the other side. You can stop in the middle and turn it off, also.
So, those two are the basic types of hand-held routers that we have. Either one of these, requires some type of guide system. Neither of these are suitable for free-handing. The router has a very powerful motor on top, and it will try to move out of your hands, if you let it. So, you'll always need guide-rails of some kind; jigs, or guide-rails that go on the router it's self to keep it aligned.
The other thing that these routers have in common is variable speed. Most routers are like this. You can change the speed that the bit is rotating. Why would you want to do that? The main reason is that different bits, depending on their size, need to be operated at lower or higher speeds. The larger the bit you have, the lower the speed you're going to want to operate it at. Imagine, essentially, that we're taking out three quarters of an inch of material, versus a quarter inch of material. The router is doing a lot more work to remove more material, and also the bit is spinning faster at the outside of the circle, than this one is. That's the reason we slow down the speed. The bigger router bit is actually moving faster at the outside edge. Usually, your router bit package will tell you the optimum speed to operate it at, so you don't have to know, or memorize that for every bit. The speed can be adjusted on the router bit, up here. There's two different styles that I have here. On this plunge router, it has a dial that goes from one to four. One is the low speed. There's no way you would know what speeds those were, unless you looked in the manual. But, they do correspond pretty closely to what's on this router. This is typical for these size routers. Your low end of speed is about 10,000 RPMs, and the high-end is about 23, or 24,000 RPM. So, depending on what size of router bit, you're going to adjust the speed, here.