Routing Slots In Wood
This article is from Issue 25 of Woodcraft Magazine.
7 simple solutions for safer, smoother cuts
Mount a straight plunge-cutting bit in your router and set the router bit to cut about 3/8 in. Deep for the first pass. A plunge router works best, but if you don’t have one, hold the router above the wood and start it. Carefully plunge it into the wood and begin moving it counterclockwise around the circle (Photo 2). Routing a road course will require different sizes and/or strips. I mark off a 3/8' wide outer cushion. There is an extra slot being routed on the outside that will be used to mount our wall. I need at least 3/8' to give it strength at the very edges.
The power behind a bit spinning at 20,000 rpms is difficult to fully appreciate, that is, until an accident happens. I learned this first-hand when my router’s collet assembly broke free of its armature. Before I could hit the stop button, the free-floating bit bounced around and chewed up the piece I had been trying to rout. Had it not been for a good hold down (and a little luck) this story could have ended with a 911 call.
Routers seem tame, but that little bit can take a big bite out of your work and you, just like any bigger-bladed machine. That’s why when parts get really small, it helps to break out the big guns. Here’s an arsenal of jigs, fixtures and sure-fire techniques you can employ to rout small pieces as safely and smoothly as possible. We’ve kept them simple so you won’t have any excuse not to use them, no matter how quick or small a cut might seem.
1 Handscrew keeps hands out of harm’s way
Wooden clamps (shown above) excel at keeping fingers clear of the action, and they won’t damage pricey carbide should they come in contact with the bit. For the best grip, tighten the front screw then loosen the back screw to wedge the wooden jaws against your workpiece. Ensure the workpiece rests flat on the table. When a piece is really thin, attach a layer of hardboard with double-faced tape to create an edge that guides against the bit’s bearing.
2 Two-Handed Hold-Downs
Double-grip hold-downs may not be twice as safe as one-handers, but they do a better job of keeping both hands clear of the bit and offer supreme control of the workpiece. Both the all-wood (Photo A) and the wood/polycarbonate combo (Photo B) are easy to build so you can make different sizes to fit your needs. In addition, the larger footprint offers better stability. Both are easy to build so that you can quickly make a few different sizes to fit your work; that way you won’t lose control lifting and repositioning
in the middle of a cut.
To make one, start with a thick piece of wood or polycarbonate and drill two holes for the 1' dowel handles. Glue the dowels in place in the wood option, or screw them up through the base with countersunk brass screws. Next, attach sandpaper or double-faced tape to the bottom of the base for a better grip. Finally, knock down sharp edges with sandpaper, but don’t spend too much time on looks or finish-sanding since the jig is likely to encounter front-line combat.
This softwood hold-down is simple, safe, and sacrificial. For a no-slip grip, attach sandpaper to the base, or attach a few small tabs of double-faced tape. Replace the tape when it loses its tack.
Use this see-through hold-down to view the board/bit contact. Polycarbonate costs more than acrylic, but this shatter-resistant material serves better for any jig that encounters a spinning bit. Drill shallow holes in the dowel handles and counterbored screw holes in the underside of the base bottom.
3 Routing Sleds Hold Their Own
The only disadvantage with hold-downs is that if you press down too hard to get more control, you could stall your effort to slide the stock past the bit. Avoid this by directing the clamping pressure to a hardboard sled that rides (and “glides”) in the table’s slot as shown in Photo C. The jig includes a hold-down clamp that allows for a rock-solid grip on the workpiece. Better still, the oversized base bridges the bit opening in the fence, eliminating the problem of having a handheld small board tip into the bit at the beginning of a cut or having the bit catch the back edge and gouge it. The jig’s backer board—another plus—prevents splintering the workpiece when the bit exits the cut.
A sled helps small workpieces behave like bigger ones. Cut the base slightly oversize and attach the fence near the center as shown. This provides even support of the workpiece along the full length of the
4 Strip Routing
When tackling the nerve-fraying task of routing the edges of thin strips, think strategy first. Wider is better, whether you’re profiling edges or routing a groove. If possible, rout the needed edges on wider stock as shown in Photo D; then rip the pieces to width on a table saw. Be sure to dimension the wider stock a few inches longer to avoid machining issues at either end of the workpiece. Finally, crosscut the pieces to final length.
Routing then ripping sidesteps the small-part problem. When ripping, position the profiled edge on the free side of the blade; trapping the strip between the blade and fence can cause kickback.
5 Two-Cut Tunnel Jig
Sometimes you just don’t have enough material to rout then rip. In this case, you need a way to keep narrow strips against the bit without tipping. Enter the tunnel jig shown in Photo E. This jig is not only simple to make, it also prevents strips from tipping and safely shrouds the bit. Unlike feather boards, the tunnel jig doesn’t press stock into the bit, reducing the likelihood of mid-cut burn marks. Cut an extra strip to serve as a pushstick when running workpieces through the tunnel.
The tunnel jig is a piece-specific jig, made from a 6-8'-long piece of scrapwood. Mark the height and width of the strip on one corner of the block, then remove that corner at the table saw (creating a sized rabbet). Clamp the block to the router table fence as shown.
6 Cross-Grain Routing Base
Rabbets, dadoes, and tenons all require cross-grain cuts. Here’s a jig you can use to rout rabbets and grooves when you don’t have much wood to work with. By sandwiching your workpiece between two boards, the jig provides a wider platform for the router’s base to slide across. These same sides also protect your work from bit tear-out, and the guide fence offers a reliable straightedge.
To make the jig, cut two sides the same thickness as the workpiece. Position the workpiece between the sides to ensure a tight fit, then screw the sides to the plywood base. Now attach the fence across the sides to serve as a straightedge guide for your router. Cut and fit a stop to slip between the sides and screw on a toggle clamp to secure the stop or your workpiece, depending on the operation. Install a bit in your router and rout a shallow test dado to show the exact location of the cut and for cutline alignment. As shown in Photo F, we clamped the jig to a bench vise, but you could also set it on a non-slip bench mat.
To rout half laps, clamp a stop between the sides so that the notch lines up with your shoulder line on your workpiece. Butt the piece against the stop, make the first cut, and gradually pull it away from the stop, moving the router back and forth against the fence as you go.
To rout dadoes, align the cutline with the notch, clamp the piece, then make the cut. For wider dadoes, reposition the piece and rout the
Softwood, hardboard, and double-faced tape: the jig-making trinity
Let’s face facts: the life of most jigs is cruel and short, so there’s little reason to sacrifice your best stock. Even if you own a pile of hardwoods, there’s good reason to stick with softwoods (pine, fir, and cedar) for most jig work. Besides price, softwoods will dent before your work will, a nice attribute when you feel the need to crank down a clamp. In addition, you can screw on fences, stops, and clamps, without needing to drill pilot holes and counterbores.
For applications requiring panels, invest in a few full or partial sheets of hardboard (1/8' and 1/4') and MDF (1/2' and 3/4'). Both manufactured panel products are cheap, reliably flat, and readily available, and you can use leftover scraps in any direction without worrying about grain problems.
Double-faced tape is handy not only for sticking stock to sleds and hold-downs but also for temporarily tacking pieces together before driving screws or cutting multiple parts. For self-sticking shim stock, simply leave the paper backing on one face.
7 Shop-Made Zero-Clearance Router Fence
Small pieces can easily slip and tip into the gap between the bit and the infeed or outfeed fence, or fall into the opening in the tabletop. This doctored fence and auxiliary top combination solve both problems. Use Figure 2 as a guide, but adjust the sizes given to fit your router table.
The fence is a basic plywood L with an added 1/4'-thick hardboard face as shown in Photo G. The best thing about it is the bevel-edged, replaceable, zero-clearance insert. Because it’s sacrificial, this insert provides more complete support than any metal fence. You can usually use the bit to cut its own custom hole, either by raising it from below or carefully sliding the fence into the bit. If the bit has a bearing, you will have to pre-drill a clearance hole. When the hole gets too big, simply flip, trim, or replace.
The zero-clearance base isn’t always needed, but it can be a part saver when the pieces get small or if you don’t own a set of base-plate inserts. To make the base, cut a strip of 1/8'-thick hardboard sized to your router table. Lower the bit below the table and position the hardboard under your fence to secure it to the table.
Routing Slots In Wood Joinery
Now raise the bit. To create a fresh zero-clearance hole, just shift the hardboard a few inches over.
A 1/4' hardboard fence and 1/8'-thick hardboard tabletop can make any router table zero-clearance. Reverse or replace the beveled hardboard fence insert when the opening gets too wide.
Woodworking is all about shaping wood. While there are a wide variety of ways in which we shape that wood, they can be broken down into two basic categories: cutting wood to remove parts and attaching pieces together. Within each of those two categories, there are several different ways of accomplishing most woodworking tasks.
For the most part, woodworking today is done with power tools; but that wasn’t always the case. If we go back 100 years, there were no electric power tools to use. While the sawmill goes all the way back to 1594, sawmills were few and far between. There was no chance that someone would have their own. The first handheld electric drill, the most common electric power tool there is, wasn’t invented until the late 1800s and was first only used in factories.
Today, we have a multitude of different power tools, allowing us to do a wide variety of woodworking tasks. The problem, for many of us, is that there are too many tools available for what our budget can support. We end up buying the tools we need the most and finding ways of making do for everything else.
This is why it’s valuable to know alternative ways of doing things. Those alternative ways might involve using other types of power tools to complete the task or they might be the methods that our forefathers used, working with hand tools, rather than power tools. Either way, they’re worth having in our bag of tricks.
The Rapid Cutting Router
For this article, we’re going to concentrate on alternatives for shaping which is normally done with a router. Routers are high-speed tools, in which a motor turns a bit, which sticks down through a base at 90 degrees. The height of the bit can be adjusted, as compared to the base, affecting exactly where on the workpiece the bit is cutting. A variety of bit shapes are available.
Routers can be handheld, with the base placed on the workpiece or they can be mounted upside-down in a router table, allowing the workpiece to be run across the router bit. Generally speaking, the router is used without the table for larger workpieces and mounted to a table for smaller ones. Some woodworkers have two routers, allowing them to leave one mounted to their router table.
A router is a handy tool to have, being used for cutting grooves (properly called rabbeting), cutting slots in boards, such as for hanging them, trimming the edge of laminate, and cutting various types of tongue and groove joints for putting pieces together. They are also used for rounding or chamfering the edges of tabletops, as well as cutting molding edges directly into those edges.
Alternative Ways to Cut Grooves (Rabbeting)
Rabbeting means to cut a groove in a board. This groove might be in the edge of the board, which is a useful way of connecting boards at corners or it might be in the middle, such as for a drawer slide. In either case, the most common tool for cutting these grooves is the router. But what do you do if you don’t have a router available to cut a groove in your workpiece?
Regardless of which method you’re going to use to cut the rabbet, you’re always going to want to start by marking exactly where you’d like to make a channel. The old rule of “measure twice, cut once” applies just as well here, as it does anywhere else. Be sure to use a straight-edge when marking to cut a straight line, not just a convenient board. It’s amazing how many boards come from the sawmill with edges you can’t count on.
Table Saw Method
Typically, grooves cut into wood on a table saw are cut using a dado blade. There are several types of these, including one where the blade wobbles side to side, cutting out the groove and one which is essentially a stack of blades. Both types can be adjusted for the width of groove that is wanted and both work, although the surface finish provided by the wobbling blade style is not as good as that provided by the stack of blades.
When cutting a dado or rabbet on a table saw, always make a test cut, as both the width and depth of these cuts can turn out to be different than what you expect. You should also measure the distance between the edge of the saw blade and your fence with a tape measure, as the built-in gauge for your fence will not be accurate with these blades installed.
If you don’t have a dado blade for cutting grooves, you can still cut them on a table saw, using the standard blade. For most table saw blades, the kerf (width of cut made by the blade) is 1/8”, although there are some “narrow kerf” blades which only cut out a tenth of an inch.
To make a wider than 1/8” groove in the wood, all that you need to do is make a series of cuts which overlap each other, moving the workpiece between each cut. If your groove travels the length of the workpiece, this can be accomplished by moving the table saw’s table. If it runs across the width of the board, you’ll need to use the miter gauge, moving the workpiece slightly between cuts.
Always make a test cut to double check the depth your blade is cutting, whenever making a cut on a table saw that does not go all the way through the board. While you should be able to measure the height of the highest tooth off the table and determine this, that measurement usually isn’t accurate enough.
Dremel Tool Method
You can cut a channel in wood with a Dremel tool or similar tool; however it is nearly impossible to get a clean cut in this manner. You can improve how clean the edges of your cut are by first cutting them with a utility knife. This will also help to prevent splintering of the edge.
Using a Dremel tool works best for short cuts, as the rotary bit on this tool is small and long cuts can be time consuming. Be sure that the bit on the tool will go to the correct depth, then get to work, following your line. You’ll finish up eventually!
Rabbeting Plane
Before the existence of routers and table saws, woodworkers made grooves in wood parts with a rabbeting plane. This can either be a wood or metal bodied plane, where the plane’s body is exactly the same width as the blade. Rabbeting planes come in a variety of different widths, up to one inch, to match the most common groove sizes used.
Rabbeting planes can be used in the middle of a board or at the edge. They can be used with the grain or for crosscutting. The major difference between crosscutting and cutting with the grain, is that you need to make sure that you use a thinner depth of cut for a crosscut, than you would when cutting with the grain.
Some rabbeting planes come with a fence, which allows you to set the width of a rabbet, when making the rabbet at the edge; but most don’t. Professionals get by without a fence, by cutting a narrow groove with a sharp knife, at the edge of where they want to make their cut. This groove can then be used to guide the plane.
If you’re not that skilled, an alternative is to clamp a straight edge, metal-bodied level or straight board across the piece you are trying to cut the groove in, using it as a fence, once you get a little bit of the groove cut, you can remove the fence, as the plane will ride in its own groove.
Chisel Method
If you’re completely desperate and have no power tools, you can always cut a groove the old-fashioned way by using a chisel. This was the normal way of cutting a groove for centuries, especially for apprentice woodworkers, who didn’t have a rabbet plane to use.
Routing Slots In Wood Chipper
As with the other methods, start out by marking where you want to cut your groove, marking both edges of the cut. Then use a back saw to cut along those lines, to the depth that you want to make your groove. Be careful on this, as it is extremely easy to get the ends of the cuts to the full depth, without getting the middle cut that deep.
With the sides of the groove cut out, it is an easy task to cut out the material in the groove with a chisel. Use a chisel that is as close to the width of the groove as possible, without going too wide. As you reach the bottom of the groove, be careful not to overcut.
How to Make Rounded and Chamfered Edges on Wood without a Router
A router is by far the best tool for modifying the edges on wood, whether that modification is creating a rounded edge, a chamfer, a beaded edge or some other type of molded edge. Many of the wide variety of router bits on the market are specifically designed for these purposes. But what do you do, if you don’t have a router available to do this type of work?
A lot depends on the kind of edge you’re trying to make. Obviously, some are more difficult to accomplish than others. Much of this involves using various types of wood planes. But before routers, planes were one of the woodworker’s top tools. Most would have a large number of planes, many of which they had made themselves and each of which had a specific purpose.
Rounding and Chamfering with a Plane
If you have a standard wood plane, what’s known as a “Jack plane” or “bench plane,” rounding and chamfering edges is easy. All you have to do is to run the plane down the corner of the board a number of times, until you get the edge you want. For a chamfer, you’ll need to hold that plane at a consistent 45 degree angle for all the strokes and to round it; you’ll want to vary the angle. To finish off the rounded edge, sand out the flats created by planning.
Always use a plane following the direction of the grain, when planning the long edge of a board. You want the grain moving up and towards the edge, as it moves away from you. Otherwise, the plane’s blade can catch in the grain, tearing out chunks of the wood, rather than shaping it the way you want.
For rounding and chamfering the ends of the board, where you are cutting across the grain, you’ll want to use a block plane, rather than the planes mentioned earlier. These are smaller planes, but the important difference is that the blade is set at a 35 degree angle to the surface, making it easier for them to cut across the grain. Always ensure that the blade is sharp, so that it will cut through the grain.
Rounding Edges with a Sander
Another option, which allows you to use a power tool, rather than working with hand tools, is to use a vibratory or random orbital sander. This will not provide you with as clean and crisp a rounded edge; but rather, an edge which looks worn, especially at the corners. Work one edge at a time, gradually removing wood, until you have created a rounded profile that looks good to you. It’s tough to be precise with this, but the finished results are visually interesting and perfect for rustic furniture and woodwork.
Of course, the same thing can be done sanding the wood by hand, although it is much more work.
Using Molding Planes
A moment ago I mentioned that carpenters and cabinet makers used to use molding planes to cut profiles in the edges of wood, before the router was invented. These planes were used for both creating fancy edges on the wood of cabinetry and furniture and to make architectural molding. Each particular profile the woodworker would want to cut required its own special plane.
The shoe of these planes would look like a mold of the profile to be cut and the blade would be ground, filed and sharpened to match that profile. In a carpentry or cabinet making shop, they will make their planes off a “mother plane” which is the reverse of what they are trying to create. The mother plane would cut the profile into the shoe of the planes they would use, then they would grind the blade to match that shoe.
You can find these molding planes for a very reasonable price in many antique shops. While they might need some cleaning up and sharpening, most are in fairly reasonable condition. Just make sure that the shoe of the plane isn’t split or have missing pieces and that the blade matches the contour of the shoe. They sometimes get mixed up.
Molding planes are used just about like you’re trying to plane the edge of the board, with the exception that they will make a contour, rather than making the edge of the board flat and smooth.
Molding with a Scratch Stock
A simple tool, called the scratch stock, was used in cabinet shops, when only a small amount of a particular molded edge was needed, such as a triple beaded edge for the top of a dresser. This tool consisted of a clamp to hold the blade, with a lip to align it with the edge of the board to be molded. There was no shaped shoe, like on a molding plane.
Blades for the scratch stock were usually ground from pieces of old, broken bandsaw blades. In the photo above, the author used a broken sawzall blade for the scratch stock. The working end of this blade is not visible in the photo, as it sticks out underneath the tool, but it is ground to provide a triple bead on the edge of a board. The end sticking up has been ground to provide a different profile. All that would be needed to use that end would be to reverse it in the tool handle.
How to Cut a Slot in Wood
Another task that is often done with a router is cutting slots. This differs from cutting a groove in that the slot does not go the full width of the board. Different types of slots are cut for different purposes. There are a few ways to cut a slot in wood without a router. The method you choose depends on the type of slot you’d like to make, as well as on the tools you happen to have on hand.
Keyhole Slot
Keyhole slots are used typically for hanging finished work on the wall. There will be an opening for the head of a screw to go through, along with a slot that is small enough that the screw head cannot pass through it. Keyhole slots can either be cut all the way through a board forming the back of the project or cut into it, depending on the thickness of the board.
These slots are normally cut with a special bit on a router, using a fence, with the router mounted in a router table, to keep the slot straight. But they were in use long before the router or the router table were invented.
Start by marking a line, showing where the slot is going to go and which end the larger hole is on. Drill the clearance hole that the screw head has to pass through at the appropriate end of the line. This is normally about 1/32” larger than the diameter of the screw head. Then drill a hole the same diameter as the slot, at the other end of your line. This is normally 1/32” wider than the screw threads, what’s referred to as the “major diameter” of the screw.
Draw two parallel lines, the width of the smaller hole, from that hole to the larger hole, ensuring that they are centered on the larger hole. Cut the material between the two holes with a keyhole saw. This is a small saw, with a very narrow blade and a point on the end.
Another way of cutting out that material is to drill a series of holes, following the line, with the smaller size drill bit. Then, cut out the remaining material with a small chisel.
Routing Slots In Wood Blocks
Cutting Slots in Wood with a Jigsaw
If you want to cut an open slot in wood, you might find that a jigsaw does the trick. Start by drilling two holes at each end of the desired slot. You’ll need to make sure that at least one hole is large enough to accommodate the jigsaw blade. Cut the slot, working carefully and moving slowly.
Cut a Slot in Wood with a Circular Saw
It’s normally not recommended to make plunge cuts with a circular saw, for safety reasons, but many woodworkers do it anyway. It’s definitely safer to make a plunge cut with a circular saw than it is to make the same cut with a table saw. For safety, before you get started, be sure that you have a good sharp blade on your circular saw. Be sure to wear the proper eye and ear protection for this task, and clamp your wood into position before you get started. Stand to the side, not behind the saw.
Routing Slots In Wood
Raise your blade guard and set the blade to the proper depth, just a bare fraction of an inch deeper than the depth of the wood.
Line up the blade with your guide line. Tip your saw up and activate the blade. Once it’s at full speed, double-check to ensure that you’re still over your guide line. Plunge your blade slowly into the wood, release your guard, and then make your cut. It’s a very good idea to practice this technique on scrap wood before moving on to anything important.