The objective of this How-To is to simplify the purchase of your first hand router as a luthier building up their base of tools. Whether you've never used a router before, never had to consider buying one or just want to go into your next purchase with a more informed choice, the next ten minutes will assist you to make an informed straight line choice.
What is a hand router?
A router is a compact universal motor that spins a rotary cutting tool at high speed, typically 5000RPM - 30'000RPM. In a hand router, the motor is fitted into a portable base to guide the cutter around the workpiece. Routers are available with a selection of bases with differing end uses, whilst some are permanently built into a more universal type of base. Routers are commonly classified by their horsepower rating from around 1/2HP (~375W) through to 4HP (~3000W) or more. The most common hand routers useful to a luthier are less than 2HP; larger motors become physically cumbersome to manoeuvre around small workpieces and routing operations are rarely as extensive as larger machines are intended to cope with.
For further information on the uses of a router, we'll be publishing a Router 101 in the near future.
The Router Motor
The vast majority of router motors consist of a universal commutating brushed motor. These are inexpensive, compact, have high starting torque and are capable of high rotational speeds. The downside is that they are generally not built to run for extended periods of time and the brushes can physically wear out. If you're interested in how universal motors work, Wikipedia is a good place to start. In general however, it is not required knowledge for judging router A from router B but it does provide useful insight into the secret life of electric motors!
Similar in purpose to a drill chuck, the collet is a locking mechanism for holding a rotating cutter. Unlike a drill chuck, collets are usually swappable between specific cutter shaft diameters. A router that not designed for alternative size collets can be somewhat limited. What size(s) does the router support (commonly 1/4", 3/8", 1/2", 6mm, 8mm, 12mm) and does it come with them, or are they an add-on purchase?
Smaller tools such as palm routers are often only capable of handling smaller shaft diameter cutters (1/4", 6mm). Larger routers on the other hand should have a wider range of tool holding capacities. Compact palm routers are adequate for the majority of guitar work, however larger cutters are commonly available with larger shanks only. 99% of the cutters used around guitars are easily found in the smaller diameters so this is rarely an issue for your first purchase.
The collet should always rank highly in the things to tick off a potential router purchase. Often, anything but the most basic aspects of the collet are overlooked despite it being something to get right off the bat.
Is the collet awkward to access and does it require specific tools to lock/unlock? A collet tightened by a simple spanner can be less frustrating than one that requires a specifically-designed tool that only comes with the router. Can you buy spares or alternative sizes? Collets can wear through use and abuse; not being able to replace the collet can lead to the entire router becoming next to useless.
The two most common types of base that come with routers are fixed and plunge. A router motor mounted to a fixed base allows the rotary cutting tool to protrude through the baseplate by a specific amount and is locked in use. Altering the cutting depth requires that the tool be powered down (and preferably isolated from the mains) before the cutting depth can be adjusted. A plunge base allows the tool's cut depth to be unlocked, altered and re-locked during working operations; the cutter can also be "plunged" into the work. Depth of cut in plunge bases is usually assisted by an incremental depth stop. Better plunge bases also have fine tuners for more accurate settings. Routers with a unibody design are generally dedicated plunge routers.
Fixed bases are far more compact and stable than their plunge counterparts. The handles to guide the machine are lower, providing better control through routing operations. Plunge bases have the ability to withdraw the cutter above the baseplate, making them safer when starting up the motor. A fixed base must either have a starting hole ("cutting air") or be advanced into the workpiece from an edge. Plunge base allows operations needing several passes to be carried out with relative ease of adjustment whilst a fixed base is able to carry out more precise, delicate work with the confidence from control.
Speed control and soft start
At the bare minimum, speed control is a huge bonus. Some harder woods are easy to burn (Maple, Cherry, Oak, etc.) and benefit from lowering the cutter speed instead of trying to move the router around the workpiece faster. This reduces final sanding work and allows the routing operations to leave the workpiece closer to a semi-finished state.
Larger diameter router cutters also benefit from lower speeds. Doubling the diameter of a cutter doubles the speed at which the outside edge of the cutter travels. Slow speeds are also a bonus should you need to use your router for cutting plastics for pickguards, templates, etc.
Heat is also a huge problem for router bits; getting too hot changes the properties of the cutter material, causing premature dullness. Dull cutters also generate more heat....
More advanced speed controlled routers have the ability to electronically monitor spindle speed and compensate for slowdown when performing tougher tasks by applying more power to the motor. This helps safety and quality of work; ensuring that waste material is consistently removed and that there are no sudden speed changes during operations. The name for this feature varies by manufacturer, each one having their own pet name usually along the lines of "constant velocity" or "constant speed".
Larger motors often feature "soft start". The nature of the universal commutated motors in routers is their ability to spin up to very high speeds in a fraction of a second. The downside is Newton's third law, "For every action, there is an equal and opposite reaction". A spinning motor suddenly accelerating will cause the body of the router to twist or jump in the opposite direction from the torque. Soft start electronically ramps up the motor speed over a longer period of time, vastly reducing kickback on first powering the motor up.
Power Switch Location
A consequence of motors having separate interchangeable bases is the location of the on/off switch. Typically, unibody routers have a trigger-type power switch mounted on a handle. Since the handles are separate to the motor itself on swappable bases, most have the power switch located elsewhere on the body itself. Some manufacturers such as Bosch and Porter Cable have worked around this. Generally smaller routers are switched only on the body; whilst not a dealbreaker it is consideration for safe use.
The beauty of a router is that they can (and should!) be repurposed in all manner of inventive and powerful ways. One example of this is a floating binding jig; commonly ideas like these involve fabricating customised motor holding jigs. Examine the base(s) that come with your router. They usually comprise a metal body with a plastic/composite base which rides on the workpiece itself. Is the base removable by screws, etc. or is it permanently affixed? If so, this enables the router to be used in hundreds of additional applications without large amounts of modification work. The simplest of these is an "offset base". Instead of a round base, a teardrop-shaped plate replaces the existing one with a handle fitted to the narrow end to allow greater stability during edge shaping.
A router that comes with bases enabling flexible modification are instantly a better choice over those that do not. A skilled luthier creates dozens of custom jigs for using their routers in new ways. Unibody routers are less flexible in this regard than routers whose motor is a separable unit.
Materials and build quality
Contrary to what one might think, plastic is not an automatic signifier of "cheap". Unfortunately, there is little indication of when cheap plastics are being used or high-temp performance plastics. Metal bodies are a good sign of solid build, however the incorporation of performance plastic significantly alters final weight. When used in combination, metal and plastics improve weight distribution and stability.
Weight distribution affects how the tool feels in use. Edge-shaping around the horns on a body becomes dangerous with tall routers with a high centre of gravity. The same operation using a router with a lower centre of gravity (fixed base, for example) is an order of magnitude safer and more confident.
In short; take the router out of the box at the store, lock the plunge to depth and balance it on an edge. Does it feel tippy and handle like clown shoes on Usain Bolt? With the router still locked, twist it around in both hands. Abuse it! Is there play in the plunge mechanism? Do the handles feel grippy? Are the adjusters cheap plastic that might break off after minor use? Find reasons why you wouldn't buy it and use those reasons to compare against other models on hand.
Your first router should to be nimble enough to handle smaller detail jobs common to all guitar projects. Bigger routers have their place however are usually too cumbersome for bread and butter work. Some tasks - such as copy shaping the outline of a solidbody - are performed better using these larger routers, but smaller motors can carry these out adequately given a patient planned approach.
The ideal first router would be something around the 3/4HP - 1-1/2HP range. These tend to be small enough to rout a headstock outline, shape the outline of a body, sink pickup routs and cut electronics cavities; the big work around an instrument. Compact palm routers are affordable, and when bought as a kit have more than enough flexibility to produce accurate and clean results for less than a couple hundred bucks/euros.
OUR RECOMMENDED BUYS
As of writing, kits such as the Bosch Colt PR20EVSPK, DeWalt DWP611PK or Porter Cable 450PK offer fixed and plunge bases. All have soft start, constant speed control and are the workhorses of many small luthier's workshops; many luthiers end up with several small routers such as these, often dedicated to specific tasks such as in binding jigs or inlay routing pantographs.
For a first purchase, routers in this class can manage virtually all jobs you would want them to and continue being useful even when you buy your second (or sixth) router.
DeWalt DWP611 kit - no nonsense and easy to work with
Bosch Colt/PR20 kit - cheap and eminently reliable
Makita RT0700 kit - upmarket from a stable of thoroughbreds