Routers are used to guide a spinning bit over a stationary work piece. They are used to shape materials and create joinery.
In addition to detailing, router bits exist for slot cutting, panel raising, joinery, and many other purposes. The router is an essential tool in every woodshop.
Small routers that are held with one hand are called trim routers. They are primarily used for edge routing in situations where the bulk of a full-size router is a hinderance.
There are several different types of routers available. Each one has its own use case:
A fixed base router keeps the bit at fixed depth as it is spinning. They are best used for edge routing where a plunge action is not needed. Fixed based routers are typically cheaper than plunge routers.
A plunge router can plunge the bit into the work piece during a cut. This is a useful feature for cutting slots. Woodworking joinery often requires the use of a plunge router.
A plunge router can do everything a fixed base router can do, but the added bulk of the plunge router makes it handle a little worse. Most woodworkers have one of each.
The D-handle makes it easier to guide the router in some applications. This type of router is a specialty model often purchased last. Only consider these routers, if you have an application in mind.
Kits contain a single motor and multiple bases. The user can mount the motor in the fixed base for edge routing, and quickly switch over to the plunge base for making joinery. The kit systems represent some of the best value in routers.
Fixed Base Router
The main router in your shop should should be a medium size model (~2HP) that supports both 1/4" and 1/2" collets. This model represents the best combination of power and weight.
The fixed base router is the best tool for a wide range of tasks encountered during furniture making. A medium size router remains useful even if you later add a larger model.
Fixed-Base Router first
A solid fixed based model is a good starting choice, because fixed base models are much cheaper than plunge routers. If you do not need the plunge feature, you can learn about routers on the cheaper model.
A fully stocked woodshop includes many routers of different shapes and sizes. No one model will do it all. A medium size model, however, can do just about anything given enough patience.
The router kits sold by some of the bigger manufacturers represent the best value in routers. If you are willing to pay extra for all base options, you will get a system that you will never outgrow.
Plunge Router Second
The most useful plunge router in a woodshop is a larger model in the 3HP range. A large, powerful router is a better platform for slot cutting. You could buy a smaller plunge router to start out with, but that would only delay the eventual purchase of a larger plunge router.
On the flip side the bulk of a plunge router makes it a bad option for general routing tasks. With its high center of gravity it is significantly more tippy than a low fixed base router. If you can, use the plunge router to fill in when the fixed base router can't get the job done.