Demystifying Hand-Cut DovetailsComments (0)
This article is from Issue 22 of Woodcraft Magazine.
An eight-step approach for getting a perfectly fitting joint, straight from the saw.
By Rob Cosman
The dovetail joint is regarded as the paramount joint of fine woodworking because it blends form and function. But the reason it's been used for centuries is because of its simplicity and strength. Making accurate dovetails boils down to having a few good tools and developing the skill to saw and chisel to a line.
After teaching hundreds of students and cutting thousands of the joints myself, I’ve developed a straightforward sequence that can help anyone cut a through-dovetail joint that requires no after-the-fact fitting. My approach covers preparing, laying out, sawing, and chiseling out the tails and pins and addresses the most common problems woodworkers encounter.
So whether you’re a beginner or advanced woodworker, I hope the next few pages encourage you to spend an hour or two at your workbench trying your hand at dovetailing—or refining the dovetailing skills you already possess. We’ll create a test joint to give you hands-on experience.
Of course, honing the technique takes time but after a few dozen corners, your speed will significantly increase. At some point you’ll realize hand-cutting dovetails can take less time than setting up a dovetail router jig, especially when doing smaller projects. Speed aside, you’ll also fall in love with the look of hand-cut dovetail joints.
Now let’s get started.
The Hand-Cut Dovetailer’s Tool Kit
To follow this joinery exercise, you’ll need a basic set of hand tools: a dovetail saw (preferably one with a rip-tooth configuration and narrow set), a marking gauge, chisels, and a few hand planes. I also use a few special tools, including a fret saw, two sets of dividers, a dovetail marker, and a palette knife. (To see these tools and for some tool-buying suggestions, see the photo and Convenience-Plus Buying Guide on page 64.)
Using low-grade (or poorly tuned) tools will make this sequence a lot more difficult, if not impossible, but I don’t want to discourage you from making sawdust. Start with the tools you own, just make sure they’re sharpened and tuned to the best of your ability. When you’re ready to step up, your experience will help you understand and appreciate the value of top-shelf hand tools.
Step 1: Prepare Your Stock
Your joint will only be as good as the material you start with. When dovetailing a drawer, I prepare all the pieces first to save time, but in this case there are just two pieces of 5½"-wide stock: a tail board and a pin board. Label each piece so that the best face will be on the “show side” of the finished joint. Hand-plane the inside face, edges, and ends to ensure that all the surfaces are flat, smooth and square. (Planing end grain is challenging for beginners; I use a shooting board, but for this exercise you may use a mitersaw with a fine-tooth blade.)
Step 2: Lay Out the Shoulder Line for Tails
To lay out the baseline for tails, set your marking gauge to the thickness of your pin board, as shown in Photo A. Next, I use a skew angle block plane to create a shallow (1/32" to 1/64") rabbet on the inside face of your tail board up to the baseline, as in Photo B. This rabbet isn’t absolutely necessary, but it helps align the tail board on the pin board when transferring the tails. Next, readjust your marking gauge so that it is 1/32" less than the thickness of the rabbetted end of the tail board and scribe a line on both faces of your pin board.
Step 3: Lay Out the Tails
To lay out the tail board, I use two sets of dividers: one set to mark the half pins at the end, and a second set to space the tails across the end of the board. (I prefer the look of a dovetail joint with half pins on the outside edges rather than half tails. I think they offer a more finished look.) Having two sets of dividers—instead of setting and resetting one with each corner—makes the layout process faster and more accurate.
Mark the half pins first (see Photo C). The half pins shouldn’t be too thick, but thick enough so that they don’t break or splay during assembly. (On this 5½"-wide sample joint, I made the half pins about ¼" wide.) After using your divider to make a shallow indent in from each edge, set it aside for use on the next corner.
Next, space out your tails. Dividers offer a no-math spacing solution; all you need to know is that the distance between the tool’s legs equals the width of one tail and one pin. Starting at the half pin mark, lightly walk the dividers across the end from one edge to the other. Adjust the divider’s legs so that by the fifth step, the divider’s point lands just past the opposing half pin mark. (That “extra” is equal to the width of the pin.)
Once you’ve found your setting, walk the dividers across the end of your tail board, as shown in Photo D but this time make deeper indents. Walk the divider from the left half-pin point across to the right, then repeat the process starting from the right half-pin to the left. When you’re done, the end of your board should have four close-fitting indent pairs. These indents are the top points of your tails.
Mark the tails on the end and face side of your board using a dovetail marker. To position the marker, place the pen in an indent then slide the marker until it registers against the pen. Draw square lines across the end grain and angled lines from the scribe line up to the end of the board (Photo E). Repeat the marking process on the opposite face. Finally, take a minute to identify your waste.
Using a wheel marking gauge, scribe a line on your tail board that is the thickness of your pin board.
Plane a shallow rabbet along the inside face of the tail board to establish an easily referenced lip for laying out the pin board.
Make a small indent ¼" in from each edge to mark the location of the half pins.
Walk the divider across the end of the tail board. Adjust the legs so that it crosses the half-pin mark by 1/8" on the fifth step.
Step 4: Cut Snug-Fitting Tails
Secure the tail board to your bench vise, as shown in the opening photo, so that it’s plumb and a few inches above the bench. With your free hand, pinch the top of the board with your thumb and forefinger, as shown in Photo F to serve as your saw guide.
When starting each cut, lift your saw to take most of the weight off the wood. This prevents the saw from biting and grabbing. After the first few strokes, allow the weight of the saw to provide the downward pressure needed to make the cut. Once you’ve started the kerf, aim the saw to match your pen line and work down toward the baseline. It’s OK if you’re off your line slightly by a few degrees, just as long as you maintain a straight cut. Slow down as you approach the scribe line. To finish the cut, tilt the saw slightly forward until the teeth touch the scribe line on the opposite face. Make all of the same slope cuts before coming back to cut the other side of the tails. Repetitive angle cuts improve accuracy.
Now remove the waste. To avoid too much chiseling, I remove the bulk of the waste between the tails using a fret saw with a narrow 12.5 skip tooth blade, as shown in Photo G. Do not cut below the baseline on either face.
After removing the waste between the tails, reposition the tail board horizontally in the vise, about an inch above your bench, and saw out the half pins. Note that this is the first cut where you’ll need to split a line. The half pin must meet exactly at the baseline to ensure there’s no gap.
As shown in Photo H, focus on holding the saw vertically and stopping the saw before cutting into the side of the tail. The baseline helps ensure a clean, straight cut. If you’ve scribed the line deeply enough, the saw will practically guide itself against the edge of the line.
Start your lines from the baseline and draw up along the dovetail marker. Saws have a habit of following pen lines.
Pinch the board to create an anchor point for the saw. This prevents the blade from skipping when you start the cut.
To remove the waste, slip the blade into the saw kerf. Then saw just above the scribe line. A close cut now means less chiseling later.
Set the saw on the waste side of the scibe line and cut the half pin opening. Try to split the line for a no-gap fit.
Step 5: Chopping the Tails
Position the tail board flat on your bench, on top of a piece of scrap. Start chopping on the inside face of the board and finish from the good face. That way, if a chop breaks through, the damage will be on the inside of the joint.
I try to chop the waste with two taps. The first strike seats the chisel in the scribe line, and the second drives the chisel halfway through the board (Photo I). Flip the board and repeat the process on the face side.
Some woodworkers undercut the baseline, I’ve found that keeping my chisel vertical and chopping straight down avoids two problems. First, a perpendicular cut eliminates the risk of exposing a gap should you need to plane off more wood than expected from the finished joint. Second, positioning the chisel against the scribe line and going straight down prevents it from pushing backwards and eating into the baseline.
Inspect your tail board. Assuming you’ve sawn to the line on both sides of your tails, the corners should be sharp. If not, use the corner of a narrow chisel to clean out the corners.
Step 6: Transfer the Tails to the Pin Board
Regardless of your sawing and chiseling skills you’ll wind up with a sloppy joint if your pins are not accurately laid out, so proceed carefully. To start, set your bench plane on its side, then clamp your pin board in your vise so that the tail board can bridge between both. If you’ve planed a rabbet on your tail board’s inside face, reference it against the inside face of the pin board. Make sure that the long edges of the tail and pin boards are flush.
While keeping the boards in position with your left hand, transfer the tail locations onto the end of your pin board as shown in Photo J. Press the side of the scribe knife blade against the tail to ensure that your mark is accurate. Use 80% of your effort on keeping the knife against the side of the tail and 20% cutting the mark on the pin board. Like sawing, mark all your right sides before your lefts. Take a second to inspect your knife lines before unclamping.
Finally, chisel small chamfers on the tail board, starting 1/16" from the end to the baseline, as shown in Photo K. The chamfers allow the glue to squeeze up into the joint and to prevent the pins from being damaged during assembly.
Step 7: Lay Out and Saw the Pins
When marking the pin lines on the face of your pin board, little details really count. For example, some students are so intent on splitting the line that they'll follow it straight through the baseline. To ensure that my lines don't run long, I tell students to strike from the baseline up to the knife marks. Don’t forget to mark your waste. (This is cheap insurance against placing the sawblade on the wrong side of your line.)
Sawing pins takes some practice. Unlike the tails, you want to split the knife lines you made on the end of the pin board. (“Splitting” means removing half of the V-shaped knife cut with your saw, and leaving half attached to the pin.) To begin your cut, tilt your saw slightly forward and start a small kerf on the back side, as shown in Photo L. Using this as an anchor point, steer your saw along the knife line on the top edge so that the blade remains on the waste side of the line and make a shallow cut along the top edge. Once you’ve established the kerf, use the vertical pen mark as a guide and saw straight down to the scribe line.
After making all the vertical cuts, remove the bulk of the waste with a fret saw and finish up with a chisel just as you did with the tail board. Starting from the inside face, set your chisel in the scribe line and tight against the side of the pin. Strike it to seat the chisel on the line, adjust the chisel angle to match the slope of the pin, then make your second strike. Again, try to complete your chisel work in two taps.
Reposition the board after chopping out the waste upright in your vise for a final inspection. Use a square, check that the sockets between the pins are clean and flat. If you need to do any paring, use a narrow chisel so that you can shave high spots with a minimum of forward pressure. Set the edge of the chisel about 1/16" in from the edge and slightly undercut the socket floor. Pinch the blade of the chisel with one hand while you’re driving it with the other (Photo M). This back pressure prevents the chisel from jumping forward and blowing out the back of the joint.
Push the saw lightly along the back edge to start the pin cut. Cut the kerf along the waste side of the knife line then saw straight down.
Pare the pin socket with a narrow chisel to maintain good control when cutting. Use a square to make sure the socket is flat.
Step 8: Finishing the Joint
I don't suggest dry-fitting your joint. I find this step not only unnecessary, but it also has the potential to be damaging. Too often, pulling apart a partially assembled joint will crush or split perfectly fitting pins. Assuming you’ve accurately laid out and cut to your lines (it’s easy to see whether or not you have any remaining knife marks) as described, you’ve already done all the required work.
Before you start assembly, gather the tools needed to put your corner together: steel hammer, small square, pallet knife, glue, wiping rag, and pounding block. (To avoid splitting the joint during assembly, make this block as wide as the joint.) Next, secure the pin board in your vise about 6" above your benchtop and apply the glue (Photo N). Don’t worry about the end grain; simply apply a light coating to all long grain edges.
Start the joint with hand pressure, then use a pounding block and hammer to completely seat the joint, as in Photo O.
(If you set your marking gauge just shy of the tail board thickness, the joint should seat completely before your block hits the ends of the pins. If not, you’ll need to pound around the pins to seat the joint.) At this point, you can remove the piece from the vise and check for square. Make adjustments with a little hand pressure, then reseat your joint with your block and hammer. If necessary, you can position a clamp across the joint to squeeze the half pins against the tails.
Now that the joint is assembled, wipe off any excess glue then plane the sides (Photo P) and inspect your work. Last but not least, date and save your dovetail work. I’ve found that these sample corners are a great way to gauge your progress.
Apply glue to both boards with a palette knife. The wet glue acts as a lubricant to help you slide the joint parts together.
Seat the joint with a pounding block and hammer. Keep your pounding block clean of glue and debris so that you don’t dent your work.
Plane the boards until the joint is flush.
Dovetailer’s Tool Kit
Meet the Expert
Rob Cosman has been woodworking for most of his life. Through his book, 12 DVDs, demonstrations, and in-person hand tool workshops, Rob has helped hundreds of woodworkers discover how to achieve higher levels of craftsmanship by using hand tools.
For more information about Rob and a list of his scheduled appearances, go to www.robcosman.com.
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