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March, 2003
Beginner's Mind:
(Lots of Photographs here, so Read Slowly As they Load! NOTE: if you prefer to bypass the chatter and cut to the chase, you can fly down immediately to Layout Procedures
Prologue —But if you're still with me after that confession, permit me to explain: call it vanity, or merely the joy of discovery, the "kid-with-a-new-toy syndrome" or whatever: I simply want to pass on the excitement I recently discovered when I found that hand cutting dovetails is a whole lot simpler than I used to think it was. Once you possess a logical way to lay out the dovetails, things go fast. You already have a method that works for you? Fine, then what are you doing here? Get back to work! I don't pretend to be authoritative, only to provide another alternative—in a way that is clear to me and that I hope will be clear to at least one other person who may have been in the same perplexed situation as I. For me, having some kind of simple and logical layout method is crucial to keeping the principles in mind until the next time I get around to doing dovetails. Simply providing beginners with a fixed dimension ("measure 1/2" from end . . . ") doesn't always work. On the other hand, I realize that what I find important may not be so important to someone else; in fact, once you learn them, the principles are so simple that I'm almost embarrassed to be here myself! So to kill time while the photos load, let me start with a bit of
Background:
I began by reading tutorials on the Internet about hand-cutting dovetails, and I also picked up instructions in several woodworking books I had in my library. Let me make this clear: it would be foolish of me to be overly critical of the instructions and tutorials provided by the many professional woodworkers out there; if you understand them and they serve your purposes, then fine. Use them and not mine! On the other hand, from my perspective, many of the explanations I read seemed to be based on the assumption of some arcane initiation. The actual cutting instructions aren't so bad. In fact, most are quite clear. On the other hand, it was the way they explained (or failed to explain) the initial layout of dovetails that always left me puzzled. To be honest, I still don't understand what some of them were talking about. Were there any proportional rules? Some said yes, some no. How did one calculate the tails and their size, together with the size of the pins between them, the relationship between the sizes, and so on? What was the principle involved? Wasn't there an easier formula? Did it require a sacrifice of blood? Everyone seemed to have a different explanation and method, and I'm sure they all seem eminently logical to the authors (after all, mine does to me, too), but none satisfied me with the kind of practical simplicity I needed as a beginner. Admittedly, my reading has been limited; I have not purchased and watched the various video tutorials for sale, and only recently have I bought a book dedicated to dovetail cutting. At any rate, when starting out, I felt that cutting them itself was relatively easy compared to understanding the process of layout!
In sum, I played with hand-cut dovetails on only a couple of occasions in late 2001. My very first dovetail practice was this: I made the above practice piece on the spur of the moment one evening when the dovetailing bug first hit me, and I have no idea now how I calculated the layout. The wood is just some very rough scraps of Japanese cedar, and I was trying to do no more than produce a three-dimensional model of how dovetails actually worked. Yes, the joints sort of fit together, but wow, aside from the sloppiness of the whole thing, look how thin those half-pins are on the top and bottom! A drawer made like this would break in no time with those thin walls.
Shortly thereafter, I used some similar scraps to make a simple rustic box.
It came together fairly well, certainly serviceable enough that I can now use it to hold fireplace matches without feeling incredible shame. In fact, I was pretty proud of it as a first effort. Somewhat later, I decided to combine dovetails with box joints to make a tissue cover box from black persimmon, but not only was the combination of joints difficult, the wood warped slightly, and all in all, it turned out poorly for a second effort. I've included a few more photos at the very end showing my more recent "practice projects"; I'm trying to learn from my mistakes! ——The point is, as a weekend hobbiest, I don't do dovetails on every occasional project, and I quickly discovered that each time I was confronted with the prospect of doing some, I'd already forgotten how I did them the last time! I couldn't remember the principle or rules of layout, most likely because I never really knew them to begin with! In sum, each occasion of building something with dovetails involved relearning the arcana of laying them out, and I would give up and decide to use some other kind of less-demanding joint. Fast forward: recently, however, I needed to make several simple drawers for an armoire renovation in our bedroom (the photo at the top of this page); at the same time I also wanted to make a drawer for a sharpening station I had planned for my attic. With these projects in mind, I finally decided to sit down and analyze the logic of dovetails in the simplest and most methodical way I could, to write down some simple rules that I could easily pick up again later without having to reinvent the wheel each time. The results I came up with are offered here as merely one possible way of doing layout, a way that involves some simple, easy-to-remember rules. My overall results are typical of a beginner and are not meant to impress, but that's not the point; I now find dovetails actually fun to do, because I have a simple list of layout rules I can go back to and immediately apply to most any dimension of workpiece, even if I've forgotten what I did before! Once the rules are there, it's also easy to modify them to make differently sized dovetails. To bring this long-winded prelude to an end (have the photos loaded yet?), the grist of what I learned about dovetail layout was this:
1. Most aspects of dovetail layout are arbitrary.
Whaaaa . . . . Too simple, you say? Okay, take a breath: the in-depth version follows. In fact, my apologies if it is excessively detailed for your experience and tastes. That's what the
A Note about Measurements . . .
My Entire Repository of Wisdom about Dovetail Angles {To produce a 1:6 bevel angle, take a sheet of graph paper, and from an arbitrary "zero" point at the bottom left, measure one unit horizontally and six units up, then draw a line from the zero point to your final end point, as shown below. That's a 1:6 bevel.}
 (Click on illustration to enlarge)
A. When making a drawer, the tails are cut in the drawer's sides, and the pins are cut in the drawer's front and back. This is an important structural issue related to the stresses that occur when you pull out a drawer. On a simple box where no pulling stresses are involved, however, it doesn't really matter structurally which "side" the tails are in; so far as I know, it's a matter of personal taste and sense of style. B. Next, the layout method I describe here is a "tails-first" system. That means you mark and cut the tails in the sides of your drawers first, and use those tails as templates for marking the "pins" in the drawer's front and back. Based on what I've read, I have to believe it's easier for beginners to understand this method than trying to do the pins first and marking the tails from the pins afterwards; (this claim refers to the common through dovetail, however; I haven't done blind dovetails yet, but I'm told that they require a pin-first layout. I'll cross that bridge when—and if—I ever come to it. At my age, I may never). C. And here's a sticky point about terminology: I'll be talking mostly about the drawer's sides, and there, the terms "pins" and "half pins" actually refer to the open "sockets" where the pins will fit. The actual pins are the male protrusions in the drawer front and back; they fit into the sockets in the sides. But you'll often hear people refer to pins when they mean sockets, or vice versa. To complicate things, the term sockets is also used to refer to the spaces the tails fit into. Got it? D. When laying out an actual drawer or box, place your four prepared wall pieces in a square or rectangle on a flat surface, and when you've arranged them the way you want, mark them so that you don't confuse what sides will be joined together. I mark matching corners with an A and A', B and B', C and C', and D and D', but use whatever works for you. Believe me, you'll be sorry later if you don't mark them in some way, because hand-cut joints are not interchangeable! E. I'm assuming all four sides of your drawer box are flat and square, and made of material of the same thickness. The baseline marking is different if the matching pieces are of unequal thickness (you mark the baseline on one piece of wood to match the thickness of the matching piece of wood) . I'm snapping some quick photos while we go, and you'll notice I'm working with pieces of pine here. This is not a preference, but they were the handiest scraps I found around the shop when preparing this tutorial. However, just about everyone will tell you that pine and other softwoods are not the ideal material for beginning dovetail practice, since the softer fibers tend to crush rather than cut cleanly when using knives and chisels. All else considered, that tends to make them turn out a bit rougher, but I'm still a beginner, anyway, so this is just a bit more practice for me, too. And remember: the primary purpose of this tutorial is to discuss layout. With that in mind, let's start by listing the basic tools (in order of use):
I'm also assuming you have a decent woodworking vise to hold the workpiece, since stability is important. Finally, I find that having a tool rack on the wall or nearby my vise helps me keep my main tools out of the way without losing them when making a project involving lots of repetitive cuts.
Layout Procedures
Sooo, off we go! I measure my material and find it's width to be 78 mm (3-1/8") and its thickness ("T") to be 19mm (3/4").
With that out of the way, I set my marking gage accurately to the value of "T" (the thickness of the workpieces, or actually, a frog's hair less)
and mark a "baseline" on all four faces at both ends of my boards
Now, place one of your drawer sides into the vise, end-grain up. Look at the following illustration and imagine how the three elements of the dovetail will appear on the face and end grain of the drawer side.
1. "Tails" (the number is arbitrary; pick a nice number that will fit easily into the available space on your workpiece. Most examples of common drawer or box construction will have between two and five tails. Just remember: the more tails you cut, the longer it will take, and the smaller each one will be, making the element of finesse more important. For this practice session, I'll do three tails.
2. "Whole pins" (or rather, their sockets): the open spaces between the tails. This number is always one less than the number of tails. In the current example, since I'm doing three tails, we'll have two pins.
3. "Half-pins" (or half-sockets): there are two of these: one on each edge, left and right; remember that the term "half pin" refers to its shape, not to its size; the actual size of half pins is basically an arbitrary decision—more design than function).
If you cut an odd number of tails, the center of the board will be a tail; if you cut an even number of tails, the center of the board will be a pin.
The next comment should be pretty obvious, but viewed from the end grain, the total length of these three elements has to equal the width of the board. See where I'm going?
Put very simply, you subtract these three elements one by one from the width of the board and the layout problem basically solves itself.
So with no further ado . . .
1. First, mark the half-pins:
2. Now that you've marked tentative points for the outside half-pins, measure the distance between the two half-pin lines on the end grain;
In my example here, I measure "A" as 62 mm.
3. Decide on how many tails you want.
Again: The number of whole pins is one less than the number of tails.
5. Multiply your selected pin width by the number of pins, and subtract this total pin width from "A.". 62 - (10 * 2) = 42 mm This remainder (42 mm) is how much space the three tails have to occupy.
6. The rest should be clear now: 42 / 3 = 14mm.
To repeat: the process starts by selecting a half-pin width, a rather arbitrary decision); measure the distance ("A") between the half-pins; decide on whole-pin width (arbitrary), subtract that from ("A"), and the rest is all tails! [There is an absurd possibility of choosing to cut so many tails that each has zero or even negative value; but that's a twilight zone I'm not going to even approach].
7. Now the fun part: Do this on the left side first, then on the right side. Repeat for as many tails and pins you have, left side then right side, back and forth, until you reach the center of the board. As I noted earlier, if you've picked an odd number of tails, the center of the board will be a tail; if you've picked an even number of tails, the center of the board will be a pin. Why measure inward from both sides?
Because all things being equal, all things won't be equal!
Now, use a try square and fine pencil to continue the marks you've made across the width of the end grain.
At the end of each line, make a tiny knife or pencil mark a bit down the face to allow you to see it easier from the face side in the next step:
9. Look at the face of the board, and use your adjustable bevel or a dovetail marker to mark the bevel lines from the end-grain marks down to the baseline on the face of the board.
Continue marking, using alternate right and left sides of the bevel marking tool.
Make "X" marks on the waste spaces, both on end grain and face!
Voila! You're all marked out and ready to cut! And believe me, it took you a lot longer to read this description than it will to lay out the tails on an actual project.
10. Finally, since you'll have more boards to do after this one, transfer your end-grain markings to a story stick;
All that remains now is to
To sum up: Next Page:Cutting the Tails & Marking/Cutting the Pins
Appendix: How to Select Pin Width
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Green Gables: A Contemplative Companion to Fujino Townshipby Norman Havens nhavens@gol.com
Updated: February 17, 2005
URL: http://www2.gol.com/users/nhavens/
