Manual chapter 4 the router
Versatile Woodworking Routers
Table of Contents
- What is a Router
- History of the Router
- Router Usages
- Types of Routers
- The Router Table
- Router Bits(cutters)
- Using a Woodworking Router
- Ten most common router bits
The router was described as "the most versatile tool in the world" by Jeremy Broun in his book, The Incredible Router. You can use a router to cut out circles, cut mortise and tenons, rout a dado groove, make copies from a pattern, and for an almost unlimited number of other things. The main application for routers is in woodworking, especially cabinetry.
Can a blind woodworker use a router?
The answer is most definitely yes. Because a router is seldom if ever used with out some form of mechanical guide to assist the woodworker with control the machine.
A guide can be a simple straight edge clamped to a work piece, a edge guide attached to the router its self, a bearing on a cutting bit, or a fence on a router table, as well as many other methods can make the router a safe, effective tool for all woodworkers.
Woodworking router deffinition
A router is a tool used to rout out (hollow out) an area in the face of a work piece, typically of wood or plastic.
The tool usually consists of a base housing a vertically mounted universal electric motor with a on the end of its shaft. The bit is height-adjustable to allow protrusion through an opening in a flat sole plate, usually via adjusting the motor-mounting height (the mechanism of adjustment is widely varied among manufacturers). Control of the router is derived from a handle or knob on each side of the device, or by the more recently developed "D-handle".
The base plate (sole plate) is generally circular (though this, too, varies by individual models) and may be used in conjunction with a fence attached to the base, which then braces the router against the edge of the work, or via a straightedge clamped across the work to obtain a straight cut.
Other means of guiding the machine include the template guide bushing secured in the base around the router cutter, or router cutters with built-in guide bearings. Both of these run against a straight edge or shaped template. Without this, the varying reaction of the wood against the torque of the tool makes it impossible to control with the precision normally required.
HistoryA device formerly used by pattern makers and staircase makers consisted of a broad-based wooden hand plane with a narrow blade projecting well beyond its base plate gaining it the nickname Old Woman's Tooth.
Today, traditional hand-powered routers are often called router planes. Although the original hand tool has a few advantages over the power tool equivalent and retains favor with some workers, since about 1960, it has all but been replaced by the modern spindle router, which was designed for the same work, although the first primitive electric hand routers appeared in the years just after World War I.
Further refinement produced the plunge router, invented by ELU (now part of DeWalt) in Germany in the late 1940s. This is even better adapted for many types of work. Some workers consider it to be the single most versatile woodworking power tool.
Modern routers are often used in place of traditional molding planes or spindle molder machines for edge decoration (molding) of timber.
Related to the router is a smaller, lighter version designed specifically for trimming laminates. It can be used for smaller general routing work. For example, with an appropriate jig it can be used for recessing door hinges and recessing lock faceplates.
There are a variety of router styles, some are plunge, some are D handled, and some are double knob handled. Some have variable speed controls. Some have a soft start feature, meaning they build up speed gradually. This is nice for routers with a large cutter. Holding a 3 horse router and turning it on is somewhat dangerous, due to the torque of the motor. Holding it with two hands is a must. For routers with a toggle type on / off switch it is important to check to verify the switch is in the off position, prior to plugging it in.
The purpose of multiple handle arrangements makes control easier with different bit sizes and configurations. For example when shaping the edge of a fine table top, many users prefer a D handle, with variable speed, as it seems to permit better control and burning of the wood can be minimized.
Usages of Routers
Uses for routers are many. With the help of the multitude of jigs and various bits, they are capable of producing dovetails, mortises, and tenons, moldings of infinite varieties, dados, rabbets, raised panel doors and frames, cutting circles, edge-join wood and veneer, plane wood, make copies from a pattern and so much more.
Some common router accessories include adjustable fences and guides, circle cutters, template following inserts, laminate joining devices and pantographs for reproducing shapes.
Router TypesThere are two standard types of routers plunge and fixed base.
When using a plunge-base router, the sole of the base is placed on the face of the work with the cutting bit raised above the work, then the motor is turned on and the cutter is manually lowered into the work. This is typically accomplished by depressing a lever with a thumb and pressing down on the handles at the same time, thus lowering the spinning cutting bit into the work piece.
With a fixed-base router, the cut depth is set before the tool is turned on. The sole plate is then either rested flat on the work piece overhanging the edge so that the cutting bit is not contacting the work (and then entering the work from the side once the motor is turned on), or the sole plate is placed manually at an angle with the bit above the work and the bit is "rocked" over into the work once the motor is turned on. In each case, the bit cuts its way in, but the plunge router does it in a more refined way, although the bit used must be shaped so it bores into the wood when lowered.
Plunge routers have a mechanism, usually part of the base which allows the router to be lowered to a stop. Often there is what is known as a turret which rotates with more than one adjustable stop on it. Typically there is a tube on the side of the motor body which can be raised or lowered and locked. The free end of this tube is aligned to lower over a threaded rod on the turret and a nut can then be spun up or down the rod to limit how far the tube can descend.
For deep cuts one might start the router, lower the bit into the stock to one pre-selected stop to make a cut and then retract the bit. The turret can then be rotated to expose a deeper stop and the router lowered to that stop to deepen the cut thus deepening the cut in increments to preserve both the appearance of the wood and reduce wear on the tool.
Another use is to start and stop cuts as in creating stopped dados or for cutting a series of specifically sized and deep holes as for example shelf pins.
For making cuts which require the bit to bore into the stock, a plunge router is most preferred for two basic reasons. The first and most important is safety. Trying to hold a router on an angle and then tilting a high spinning bit into a work piece can cause the bit to catch and thus causing the whole router to be yanked out of the woodworkers hands. Therefor, utmost caution must be taken if this kind of cut must be made with a fixed base router.
The second reason is accuracy. When a spinning router bit is lowered straight down with the base plate lying flat much more control is possible. With the addition of a template and guide bushing very accurate cuts can be made.
A router table can add a lot more versatility to your router. In fact, there are some cuts you can only make with a table mounted router. Using raised panel bits for example, can only be used safely with a table mounted router. When a router is mounted in a table, it becomes a stationery tool.
Router tables are most commonly horizontal with the router mounted up side down with the cutter pointing up through a hole in the table surface.
Like routers, tables come in a wide variety of styles. The three most common are;
Bench top or portable table. This type is smaller, usually less than 24 inches by 24 inches. The bench top router tables have short legs and are designed to set up on something like a work bench when being used. Typically with this type of table the router is mounted directly to the under side of the table.
The full sized table. This type of table is larger. A common size for this table is 32 inches long by 24 inches wide. The table can have legs that raise them off the floor or can have a cabinet under the tabletop.
A full sized table will normally have a removable aluminum or plastic plate. The router is then mounted to this plate.
Most router tables will have a miter track and a fence with a bit guard. Because a router creates a lot of saw dust many fences have a dust port in the middle for use with a shop vac or larger dust collection system.
Unlike a fence on a table saw the router fence has a wooden face. This face slides apart in the middle to allow the router bit to be positioned partially behind the fence. The opening in the fence also allows for dust collection.
Another difference with a router table fence is that the angle of the fence does not have to be square with the table edge. The fence can be on angle with the table and it will work just fine because the bit is cutting perpendicular to the fence. A major exception to this is when the miter track is being used in conjunction with the fence. In this case the router fence face does have to be 90-degrees perpendicular to the router table top.
Other Table Types.
Some router table companies make a router wing accessory you can add to the side of a table saw.
Extensions are normally made of cast iron or a lighter composite material. The best thing about this arrangement is its space saving feature. You can use your whole table saw top as well as the router table extension.
Horizontal router tables are sometimes used with the router being mounted horizontally and the cutting bit protruding through a wall at the rear of the table. This type of setup is safer and easier for some type of applications.
Router bits are the key to a routers versatility because of the wide variety of profile designs. Note a list and description of some of the most common bits are listed at the end of this chapter.
Parts of a router bit consist of the bit shank, cutter and sometimes a bearing. The bit shank goes into the collet. The collet is then tightened with a wrench. For safety at least two thirds of the shank must be in the collet. However the bit cutter should not touch the collet it self. A good rule of thumb is to put the bit all the way in the collet and then pull it back out about a sixteenth to an eighth of an inch.
Note: one quarter inch and half inch shanks are the most common sizes in the US.
Router bit cutters are comprised of flutes, (the sharp part of a router bit). A bit can have 1, 2, or 3 flutes depending on design and application. Bits which are designed to cut along the edge of a work piece will typically have a ball bearing. The bearing rides along the edge of the work and acts like a fence to guide the router and also control the depth of cut.
A recently new type of cutter some manufactures are using have an anti kickback feature built on the cutter to provide added safety.
Using a router
As with most power tools the feed direction is very important, both for safety and the quality of the cut. When using a router the leading edge of the cutter should contact the work first. When holding a router with the bit facing down the bit will be spinning clockwise so the leading edge of the bit is on the right side of center of the bit.
For example, a woodworker has made a picture frame and wants to use a hand held router to make a decorative profile around both the outside and inside edges of the frame. The hand-held router should always move counter-clockwise around the outside edge of the frame. This will insure the leading edge of the bit will contact the wood first. This direction moves the router against the rotation of the bit, causing the bit to pull the router against the work piece.
To cut a profile around the inside of the picture frame the router is moved in a clockwise direction. Again this will insure the leading edge of the bit contacts the wood first.
Conversely, when a router is mounted in a table. The router bit is protruding up through the table top so the bit is spinning counter clockwise relative to the work piece. In this case the leading edge will be left of center of the router bit. So using the picture frame example from above the feed direction will be the opposite, clockwise around the outside and counter clockwise around the inside.
When using a router table the woodworker is tippically standing in front of the table. So when looking at the table in this position, the miter track is closest to the woodworker, then the bit and the fence is on the other side of the table from the miter track and bit. The work piece is moved from the right to the left past the side of the router bit closest to the miter track.
Important! safety precaution.
Making a cut in the opposite direction than the ones described above can be dangerous. When making a cut in the proper direction the cutter is forced into the wood and thus provides resistance and requires firm steady controlled pressure to make the cut. Moving the router in the wrong direction causes the cutter to want to climb the wood and self propel the router along in the case of free hand use, or to throw the work piece when using a router table. This type of cut is known as a climb cut. Although there are times when a climb cut is necessary, extreme caution must be observed. This is an advanced technique and should be avoided by the woodworker at least in the beginning.
Feed RateThere is no hard and fast rule regarding the speed of a cut, because there are so many factors that come into play. The hardness of the wood as well as the moisture content will affect the feed rate. Other factors include size and condition of the cutter, the depth of cut and the power of the router motor will determine the feed rate.
A good rule of thumb for making a simple profile cut is to make a smooth steady cut with out stopping. Note, if the cut must be halted before the cut is complete, move the cutter away from the wood before stopping the motor to prevent burning the wood.
Too slow of a feed rate can leave burn marks on some types of wood and too fast can cause the cutter to tear the wood fibers leaving a rough cut or even damage to the work piece.
It is always preferred, although not always possible, to make many shallow cuts until final depth is reached verses one single cut. This will help prevent burning the work, tear out and preventing unnecessary wear and tear on the motor.
Here is a simple rule of thumb for determining feed rate, assuming the router speed is set correctly for the bit. If the bit burns the wood, the feed rate is too slow. If the wood chips or blows out ahead of the bit, the feed rate is too fast. Granted these are generalizations and there are other factors that could contribute to these problems, but they remain important clues about what you may be doing wrong.
Ten Most Common Router Bit Profiles
A beading bit is similar to a roundover bit (below) in that it applies a rounded shape to the edge of the stock. The difference between a beading bit and a roundover bit is that the beading bit also cuts a square shoulder on the top and bottom edges of the roundover. Beading bits often have a bearing tip for riding along the edge of the stock as it is cut.
A chamfer is a 45-degree angled cut on the square edge of a piece of stock. Chamfer bits are versatile, in that one bit can create a number of different-size chamfers based on the depth of the cut. As with the beading bit, some chamfer bits have a bearing-tip that rides along the edge of the stock.
A cove profile is designed to apply a concave, rounded profile. Often, the cove bit is used to match a beading or roundover shape on the corresponding piece of stock. For instance, drop-leaf tables use matching cove and bead profiles (called a rule joint). The cove bit often has a bearing-tip for riding along the edge of the stock. The cove profile is not to be confused with a round nose bit (below), which is used to make round-bottomed grooves in the middle of a piece of stock.
Dado (Straight-Cutting) Bit
There are a number of methods that can be used to cut a dado profile, which is a square channel in the middle of a piece of stock. While there are specialty saw blades used for cutting dadoes on a table saw, a dado can also be cut with a router using any of a variety of straight- cutting bits. These straight-cutting bits come in a variety of sizes, they are all similar in that the bit is designed to cut a flat bottom and square sides. Some straight-cutting bits have a bearing-tip (designed for trimming a piece of laminate applied to the face of a board), but these bearing-tip bits cannot be used for cutting a dado.
The dovetail bit is most famous for use in creating tails for dovetail joinery. However, dovetail bits can also be used to make tapered dadoes and rabbets. A dovetail profile has a flat bottom with angled sides which are wider at the base. Most dovetail bits do not have a bearing, although a few specific template-style dovetail jigs require abearing on the shank of the bit.
The Ogee bit, also referred to as a Roman Ogee creates a compound, S-shaped profile. There are a number of variations on the Ogee profile, with shoulders on the edges or points in the middle of the profile. As with other edge bits, Ogee router bits often come equipped with a bearing tip.
Simply stated, a rabbet is a dado on the edge of a piece of stock. While rabbets can be cut using a table saw (with a dado blade) or a straight-cutting router bit, there are also specially-designed rabbeting bits, designed to ride along the edge of the stock (often with a bearing tip).
Round Nose Bit
The round nose router bit is similar to the cove bit, except that it is designed for plunge routing grooves and flutes in the middle of a piece of stock. Round nose bits, sometimes referred to as core-box bits, can be used to cut shallow, rounded-bottom grooves of various depths, but to be used properly, the bit should be plunged until the profile cut into the wood creates a full 180-degree arc.
Roundover Bit As mentioned above, the roundover bit creates a rounded profile on the square edge of a piece of stock, and differs from the beading bit in that no shoulders are cut. Often, only a portion of the roundover bit is used to create a partial easing of the edge rather than a full 90-degree arc. As with beading bits, roundover bits sometimes have a bearing- tip.
Think of a V-groove profile much like a double-chamfer profile to be plunged into the center of a piece of stock, similar to the way the roundnose bit is used. In this case, however, the profile is a V-shape in the stock. The V-groove bit can be used at various depths to create grooves of a variety of different widths.