The router is one of the most flexible and versatile tools in the workshop. However, unless you have used one a few times the uses may not be obviously apparent. What is more, their use grows enormously as you learn that much of the technique with routers is the production and use of jigs to expand the range of tasks they can safely do.
A router holds a router bit (or a “cutter”) and spins it very fast. Different cutters will allow all sorts of different cuts to be made. They are versatile tools used for joint construction in the workshop, and also for many decorative and edge moulding purposes.
Cutting groves, rebates, flanges. Making mortise and tennon, lap, and dovetail joints (among many others). Profiling, rounding over, sculpting of edges for practicality and decoration. You can use them for fitting locks, and hinges, jointing kitchen worktops, or making staircases.
Routers come in two basic types: “plunging” and “fixed base”. While the fixed base variety is common in the US, it is rarely seen in the UK. The plunging type is generally thought of as being the more versatile, while the fixed base type may have the edge for quality of finish.
The types are further sub divided into power ranges, and “collet” sizes. The collet (the chuck that grips the shank of the cutter) dictates the size of the cutter shank. 1/4" and 1/2" are the most common sizes, although 6mm and 8mm are not unheard of. The larger sized shaft is stronger and hence able to deal with either larger cutters, more power, and deeper cuts with more material removal per pass. Many 1/2" routers will allow a collet reduction adapter to be fitted to enable use of the smaller shanked cutters. 6mm and 8mm bits are less widely available. 6mm is more often used in continental designs and does not offer any real advantage over 1/4". The 8mm however can be handy for owners of 1/4" routers, since some of the larger cutters that are not available with a 1/4"shank, are available in 8mm and many 1/4" routers can be fitted with a 8mm collet.
This smallest routers (if we ignore the tiny ones assembled from die grinders like the Dremmel) are often sold as laminate trimmers. The are typically very small and well suited to edge profileing tasks. Often they will be comfortable to hold single handed, single speed (and usually pretty fast at >20k rpm). Total power will normally be 600W or less. These are not ideal general purpose routers, but are very handy to have around in addition to a bigger tool. Many laminate trimmers are also of a fixed base design.
This class of tool is typically 800W or less with a 1/4" shank collet, and is lightweight and easy to handle. These are ideal for decorative work, laminate trimming, and edge profiling. They can also be used for the lighter joint making tasks. Usually of a plunge design.
This is the most versatile tool and can be pressed into service for most tasks. Power will typically be in the 600W to 1600W range. Collet size typically 1/4". These tools are a bit bigger and heavier than the smallest ones, but will do all the things the small ones will do as well as being more useful for machining joints and mortises. This size of router can also be used to good effect inverted and mounted in a router table.
Typically a 1/2" collet machine with power of 1500W to 2500W (or more). These tools are much heavier (often over 5kg) and hence far less suited to hand held work like decoration and edging. They come into their own when big heavy cuts are required, and when used with the larger joinery tasks, like kitchen worktop jointing, or staircase string manufacture. They are also ideal for use in a table where they will safely turn the biggest cutters for things like panel raising (i.e. chamfering the edge of a panel that will form the central part of a door assembly).
For many people buying a router will actually be the first of several. Often it takes a while of using one to find out which characteristics and features are of most use to you. Also one size does not fit all, and a combination of different sized tools can be very useful to complete some jobs. The ideal first router is the medium sized 1/4" collet machine. Small and light enough for hand held use, but man enough for many jobs.
When a router is being used for edge finishing and decorative work the quality of the finish is all important. The main factors that will govern this are the quality of the main bearings (i.e. how smooth and true the bit rotation is), and the quality of the plunge mechanism - the less play or backlash in it, the better. Smoothness is the key.
Side fence: This is used to guide the router along the edge of the work piece.
Fo all bu the smallest routers, variable speed: is needed to be able to match the type of bit in use. Bigger diameter bits typically require less speed. Too fast and you run a greater risk of snapping a bit off its shaft, burning or scorching the work piece. Too slow and you risk a rough quality of finish to the cut.
Depth lock: This vital mechanism locks the router at a fixed depth of plunge. If poorly implemented you run the risk of taking passes over a work piece where the depth of cut varies due to the plunge mechanism slipping as a pass is made.
Dust extraction: Some ability to catch the dust produced is very useful since routers can produce very fine dust that will otherwise remain airborne for a long time and may injure the operator.
Depth stop: This allows you a way to preset a maximum depth of cut. Some routers use a turret system that allows you to preset several different stop positions which can then be selected quickly with a partial turn of the turret.
Switch lock: It is becoming increasingly common in these health and safety conscious days (read nannyism!) to remove the facility to lock a power tool into the “on” position when it is not being held. If you ever want to use the router in a table however, then some form of switch lock becomes essential. Some routers still have a switch that will lock on, and others can be modified with the addition of an external switch lock. Switch lock is also handy on small routers when “cutting out” or profiling circular shapes. Unless you have rubber arms, keeping a power switch held down through 360 degrees of rotation can be difficult!
Soft Start: Brings the motor up to speed over a couple of seconds. This eliminated the “kick” at start-up and makes it simpler to align the tool ready for a cut before turning it on.
Feedback speed control: Sets the speed to an absolute setting. It increases the power fed to the bit as the load increases, ensuring the speed remains constant. This will help keep your cutting finish consistent and the speed in the appropriate range for the bit. Beware, however, that it removes one of the audible indications that you are trying to take too deep a cut in one pass. The shank of the bit snapping, lumps of wood flying about, and smoke are other clues!
Fine height adjuster: Ideal when making complex joints, like the dovetail, where the height of the bit dictates the fit of the joint. This is usually a knob that can be turned to wind the plunge height up or down in small accurate increments. Some routers use an add-on height adjuster that engages with the depth stop turret (making use of depth-stop and fine height adjustment at the same time impossible), others have it built in as a separate control which can be engaged when required.
Micro adjustment on the side fence: Allows more precise changes to the positioning of the fence, and hence better control of the amount of material removed per pass.
One of the most useful additions for a router is a router table. This turns the tool into a fixed machine that can take on extra tasks that would not be easy or safe when using it hand held. In a table, the router is generally inverted so that the bit protrudes upwards through the table, and the workpiece is fed into the fixed rotating cutter. Big powerful half inch collet routers work really well in a table, although the medium sized machines can also be used.
Router cutters spin very fast (up to 30,000 rpm), so do not underestimate the speed with which they will have a finger off - it will be gone long before you even feel it! This becomes even more of an issue when the unit is mounted in a table and both your hands are freed from holding the tool. Good guards are clearly essential.
Always treat this tool with respect. Use clamps and hold downs to fix work in place. Use a push stick or block to feed work onto the cutter to keep your hands away.
Make sure when feeding wood into a fixed router that you are doing so against the rotation of the cutter. Do it the wrong way, and the work piece can be grabbed from your hands and flung across the workshop at 80 mph. For someone standing in the wrong place, this can be an experience rather like being on the pointy end of a crossbow bolt!
Good dust collection and respiratory protection is essential, especially when machining hard woods (the dust of many being toxic). Routers are capable of machining a very finely finished surface, leaving it mirror smooth. This does however imply they are capable of generating very fine dust (sub-micron) that once inhaled is very difficult to get out of the lungs. The effects of fine dust inhalation are also cumulative.
Ear defenders are a must. It is easy to be lead into a false sense of security since a medium sized router of good quality may not seem that loud when running. However the moment a cutter comes into contact with wood the noise will get much louder, and it is often concentrated into a narrow frequency band that will dull your hearing quickly, and will cause permanent damage with prolonged exposure.
The first and most useful general purpose cutters are the straight fluted ones. These will plunge, grove, rebate, and mortise. After that, many people will want some decorative edging bits like a round over, or ogee profile.
Good cutters are expensive, carbide edged, and worth looking after. Cheap HSS cutters are at worst a waste of space, and at best handy for infrequent use in soft woods. Don't be influenced in your choice of router by the “bargain” of having 20 cutters bundled with it.
If you get really serious about woodwork you may end up with a cutter collection worth many times the cost of the routers!
Jigs can be as simple as a straight edge guide, or complex machines in their own right such as a “router lathe” (see Trend Machinery PDF document). Jigs greatly extend the range of tasks you can perform . Many jigs are simple to make yourself, and many can be bought ready made, including ones for tasks like making dovetail or finger joints, mortise and tennon joints, jointing worktops, hinges and locks rebating, making letterboxes, and chopping out rebates for stair treads. Full details of these are beyond the scope of this FAQ, but many examples can be found on specialist routing manufacturers sites like Trend Machinery, or online tool vendor Axminster Power Tool Centre. There are also many good books on the subject available, such as “Woodworking with the Router”.
Make sure you get the important accessories like the dust extraction cowl, tools for bit changing, etc. Check for a smooth plunge action and a plunge lock that stays done up! Cutting a rebate or grove that you find gets shallower and shallower along the cut is very irritating and the sign of a plunge lock that does not work well enough.