Because of their rather specialized use, routers are one of those tools you may or may not see in the workshop. They're used for doing detail work primarily in wood, but are also used on soft metals and plastics. There are 2 main types of routers – fixed base and plunge. The former comes with a stationary base plate whose height can be adjusted for bit depth, and the latter is able to “plunge” down into the work piece by sliding vertically on 2 cylindrical shafts.
Fixed Base Routers
Due to the design, fixed base routers are often the router of choice for mounting to router tables. They are also often made with bigger and more powerful motors to accommodate various profiles. I personally find fixed base routers easier to use when doing uniform work such as putting a bevel on many pieces of trimming. “D” handled fixed base routers are one of my favorites for doing repetitive corner detail as the handle shape gives you more power and control when pushing along the workpiece.
The obvious strong point going for plunge routers is that they can go both ways. – In other words, they're plunge routers but they can also lock down to be a fixed base as well. The main drawback is that the handles are designed for pushing and pulling – away from and toward you, not side to side. So although ideal for intricate detail work such as free-hand letter routing or other free-hand designs, plunge routers are probably not the best option for say, routing out long stretches of trimming.
Having said that however, there are more and more new designs coming out every year with new features, so you can't really put anything into a box.
Routers can be used for almost anything stopping only at the limits of your imagination…and your bit selection of course. What you previously labored long and hard with a chisel and hammer to do can most likely be done easily with a few strokes of a router. For example, I remember spending literally hours trying to recess door hinges with a chisel, but soon discovered I could accomplish this task with a router in a few minutes – and with much better results.
In the artistic department, routers are widely used for digging letters and other artsy designs into wood and can do so using a variety of methods. There are inlay kits with various shapes, french curves, and letter stencils that your router can follow to achieve amazing detail and precision. Routers often come with what's called a “template guide bushing” which is basically a metal sleeve that is mounted onto the base plate partially covering the bit from above, which you then push up against the stencil or inlay for accuracy.
Other apparatuses that aid in precision are the “straight guide” and “guide bearing”. The former is simply a fence that is secured onto the base plate and pulled up against the workpiece to guide it along (much like a saw guide), and the latter is a bearing that is built onto the bit itself, either below the cutter or above depending on the bit. This bearing is pulled up against the workpiece and rolls along while the cutter section of the bit does the routing.
A few tips and things to watch out for:
– Be aware of the direction the bit is spinning in relation to the direction you're pushing the router. This is crucial for edge and corner work where you're pushing the router along the edge or corner of a piece of trimming or other finish board. The bit must enter the workpiece spinning in from behind and removing material as it leaves from the front. Doing this in the opposite manner will result in disaster. Rather than do what it's supposed to, the bit will try to “skip” along the workpiece, most likely causing irreparable damage. Watch out!
– Make sure you tighten the bit down well enough – for obvious reasons! Loose bits are not only extremely dangerous, but even if it doesn't come completely loose, it can change the bit depth partway. I've had this happen to me and it wasn't fun having to redo work simply because I failed to tighten a bit.
– If you're using a collet adapter sleeve, you may at times find it difficult to remove the bit from the sleeve. This may seem obvious, but spray some grease into the offending areas and this will quickly solve your problem.
– When trimming or routing thin boards that don't allow your router to sit atop it in a stable fashion, you'll want to line an identical board of equal height next to it to provide a wider seat. This will ensure your router maintains a uniform level throughout your cut – which is very important. And on a similar note, you should secure your workpiece so it doesn't move during your cut. Simply sandwiching your workpiece between 2 appropriate boards clamped or screwed into your work table is usually sufficient.
– Make sure your router has enough muscle to perform the task you have in store for it. Driving an under-powered router past reasonable limits will result in wasted time, ugly burns and dull bits at best, and possibly even an over-heated, broken tool. An alternative if this is all you have is to make several shallow passes instead of one or two deep ones. This is considerably more time consuming but better than what's surely to come if you persist in the above mentioned foolishness. Trust me, it's not worth it.
– Having a wide base plate is beneficial when needing to scoop out a wider area and don't want your base plate slipping into the section you already routed. Doing the two ends first and leaving the middle for last will often do the trick, but it's much less of a headache if you simply have a wide base plate to begin with. Many manufacturers make wide base plates that can either be attached onto an existing one or be mounted in place of one. Just make sure it fits your model before buying.