Dovetail Sizing—Keep It Simple

It’s the practicality daily woodworking brings: exceptional practicality!

A question is raised quite often about dovetail sizing. Is there a formula woodworkers use, an industry standard? Because we don’t always make them often enough we can find the issues surrounding sizing and proportion confusing; pin size in relation to dovetail sizes would indeed be simple enough if all drawer and box stock size was truly standard and all the same but of course that’s never going to happen. Most box and drawer sizing is determined by many factors and most often they are not 1, 2, 3 or 4 units in size but more likely 1.35 units or 3.68 and any size in between. So a drawer is more likely to be an awkward 3 7/8″ tall or 85.8mm tall instead  of an easily divisible number like 4″ say or 10cm.

Me at the bench working out how to explain to you what I do to size my dovetails.

This alone makes scale and proportion almost impossible to standardise using non mechanical means. Mostly it comes down to what aesthetically pleases you. Because most customers know so little about this element, they simply cannot generally care too much about these proportional sizings; they are relying on you and all they actually want is to see dovetails. One thing they generally know is that dovetails are the magic joint that holds all things together for life—hand made means dovetail joints and seeing dovetails leaves them feeling secure.

Here is my first ever teaching box where I used the box as the vehicle for teaching and training 5,000 dovetail makers the art of dovetailing. It’s been one of my greatest successes and I still love the supremely strong look I find aesthetically pleasing.

I’ve heard of and seen some different methods developed to systematically size pins to tails and tails to pins; some are mechanical but when it’s too mechanically developed the rhythm becomes lost for me, and of course the worst examples are when the machine over engineers the end result. That’s because there’s no ‘flex‘; it’s become exactly that, mechanical, automaton, thoughtless. So that’s the reason the eye picks the hand cut dovetail and the machined ones and sets them apart. Simply looking at the wood, sizing its portion, eying the grain in its configuration, depth of colour, contrast, weighing up its growth seasons recorded there in rings and such like that, I ultimately rely on my eye to judge which tails and pins I think would work best. So indeed it’s a question of sizing the pins and tails that determines the better outcome—not always the easiest of tasks for anyone, let alone a novice woodworker with aspirations for that perfect box.

A dismantled vintage drawer with larger dovetails and smallish pins.

To begin my dovetails I rely often on sketching something directly onto the wood. Just to see how I feel about it. But then too, often, a sketch drafted out on the wood leads to the section of wood traced out on paper or card. Solidity in lines leads me on into the organic spheres I flex to always embrace in all I reach for. It’s an aesthetic you see, and you you don’t need a MA in physics to get there. You never did! Once you set certain parameters, retain a flexible versatility, you open doors in dovetailing you never dreamed possible. That’s what I love about my work. Without diktats I am free to deliberate and choose. But though the end appearance requires a degree of high self-demand, I am still responsible for discovering my options, choosing sizes and proportioning tails and pins according to drawer sizes and so on as discussed. There is no sway by an individual power and then on the other hand no sway of popular opinion either. It’s a strange thing that something like joint making seems to always require those rigid lines of inflexibility we work to in the cutting of them yet the hand, the arm, the fingertips all continually flex in the handle to steer the saw. Steer?

Flex, flex, flex. loosen that grip! Let the saw glide, relax into the work and the saw will almost take over.

I use the word ‘steer’ decisively because sawing and tool use can indeed be a bit like steering a car or a bike. If you hold the car steering wheel bull-dog rigidly it’s likely you will crash because you have not got the flex you need to steer the car according to the nuances of the road and the tolerances in the mechanical linkage of moving parts in the car itself. Anyway, at the end of the day it’s about a crafting man and woman relying intuitively on their muscle and tendons to steer and guide. The small shifts make the big differences to the whole. Linkage needs flex when related to hydraulics, valves, pistons, muscle and sinew. In my world I make my decisions based on a right earned by accepting these early disciplines in my life. I understand the essentiality of being flexible because I must move my whole body in relation to the hand on the saw handle to make my cuts in the places of exactness I demand of myself. Alongside this, coupling it to me in my ongoing research and study, I find integrity in my working of wood when it comes to every element. I look always for the hidden skill, skill that then lies deep inside the joints I make. It’s called integrity. I don’t ever look for ease as such, or dumbed-down alternatives in methods that deny me achievement. Woodworkers regularly ask me why I don’t gang up the cutting of half a dozen dovetails to be sawn through all at once. It’s mostly because I know where the question comes from.

Go ahead, draw onto the wood. Stand back and look, slide it into the opening. Feel for it.

Our being programmed in school carries on through to adulthood. It starts early and we are being geared up for fast and mass production. Not a whole lot different than teaching kids to type via gaming on devices so that when school age ends we have programmers. Better to look for what gives the greatest levels of fulfilment and, yes, enjoyment too. With my struggling came experience. I crossed a line and discovered what I was looking for, that which I never found using methods other than my hands. I realise now that, often, many that criticise my quest to reestablish high levels of skilled workmanship are those that never found what I speak of. For some it’s their attachment to the conclusion of the work rather than the process throughout the making. This I found personally to be of much greater importance, adding great value before the conclusion comes. So it’s here where I unite the process with the conclusion knowing that the work I do is indeed mine. I suppose this ‘me‘ in the process is 99% hand work resulting from the skills I have mastered that give a guaranteed outcome. My work is always fast and efficient. To draw it out and prolong tasks in some etherial spheres would be more a luxury I don’t particularly want or look to. Watching someone recently combine machine methods with some additional hand tool work took two hours for what is essentially 20 minutes very pleasant and rewarding hand work. The outcome was less than it should have been for a professional maker, but I doubt he knew it.

My apprentice John some years back challenged himself with a mass of dovetails.

Dovetail proportions

Your task is to decide proportion in relation to your box or drawer, cabinet or project part. One, two, three, four—how many should this section of wood have over this one? Is it pure preference and what choices do I need to make if any? Wood type? Strength or weight-to-strength ratio in relation to use? Or is it based on something else? Well, whereas some may claim that there is an industry standard, in reality there really isn’t. Perhaps I should say at least there has never been one in any of the realms of woodworking I’ve ventured into. What determines the proportions generally are the size (height) of the corner they will create, the size of the dovetail pins and the size of the dovetails. Beyond that there are variations on the arrangement of the dovetails because you have half-lap dovetails and hounds-tooth dovetails, progressive sizing and so on. I think for the purpose of simplicity we will stick with through or common dovetails. Then from the basic foundation you can adapt the theory for other dovetail types.

My workbench becomes a combination of drawings and tools and wood.

In most work you will find that dovetailed corners form the union of the four parts to dovetailed boxes. That being so, only occasionally do they go wider than say around 6″. In projects on our woodworking masterclasses we have gone up to 16″ and around 12″. This has been for tool chests and the carcass of a wall cupboard. Lets focus on smaller widths up to the 6″ span I mentioned.

John’s box is like a castle wall of strength.

It doesn’t take long to realise that there are some variables in sizing but that boxes are usually sized from around 1 1/2″ to 2″, between 2″ and 3″,between 3″ and 4″ and then between 5″ and 6″ tall. Over the years I have developed  a system to follow that works well enough for me. For drawers, boxes or trays 2″ or less I generally like a single dovetail. For 3″ to 3 1/2″ and less two dovetails, for 4″ three dovetails, for 5″ to 6″ four dovetails and for 6″ four or possibly five.

Standing them up like this helps me to see the wood as drawers before I make them.

After that the maxim I use for myself is never to have a dovetail wider than 1 1/4″ and not usually narrower than 7/8″. That way I can work out the size according to the number of tails I want and then to the sizing of the pins too. Of course you can have more or less dovetails than I have suggested, it’s up to you. It’s more suggested practices that work that I’m offering here rather than rigid law!

Whether it is snobbism or poncey I am often unsure. Perhaps it’s neither, perhaps both, but pretentiousness is very real whether we know it or not. It does not take very long if you examine enough vintage furniture to realise that the industry standard with regard to tail sizing for fine dovetailing in fine furniture, skinny pins and wider dovetails are the goal. I like this in some measure. What I have seen in my dismantling furniture and close examination of dovetails is that if the pins are super thin they are also weak. I have also seen it in my own work where inserting the tails into their recesses resulted in the pin coming out of its socket in the main body of wood with the dovetailed piece. You see some woods are quite brittle, some have short grain and some are quite weak. You must consider the wood you are using if you plan on using thin pins.

 

 

By this, drawing out on paper and blocking out on wood, I can best see how things will ultimately look before I even start the joinery. It may be an hours work, but confidence is boosted by simple things like this. It’s well worth the time.

Following the numerical maxim suggested above simplifies the thought process for subsequent steps. Of course it is not a hard and fast rule, and indeed we have made boxes with twin dovetails in material less than 2″, but this has been to create an exercise in accuracy for training. So the remaining factor for the single-dovetail-two-pin scenario is what size pins and what size dovetail/s? Is it equal thirds? Half pins always? Well generally those of us raised with the advent of the router bit usually shy away from equally sizing our pins and tails because in the early days of the router method the pins and tails were always the same size as each other and half pins come mostly as a result of a specific type of layout methodology. Often this was generally the first of the telltale signs in detecting just how a set of  dovetails were cut. Of course in those days only real wood was used and not plywood or other engineered boards. Today the industry has shifted and I frequently see dovetailed MDF and pressed fibreboard.

This chisel tray had busy grin and did not need busy dovetails so I settled on a single tail and it worked.

Structurally I have looked for pin strength in dovetails as the dovetailed aspect is always strong because it is always at least as wide and mostly wider than the pins. In my own work I aim for a minimum size of 1/4″ and mostly 3/8″. Now that doesn’t mean I won’t go down to less or up too. Just that somewhere around 3/8″ has bags if strength without being too large and I like its proportions because, well, it has the appearance of solidity and strength. So let’s jump to multiple dovetails as generally speaking there is a predominance of this in our work.

Here the out pins are slightly bigger because it gave balance and it was easier to size the intermediate pins.

In my work I often lay out my dovetails on a section of wood cut from the stock of my tail pieces. I also might use some card stock or if i am working from drawings i will have either full size drawings are scaled drawings to work from. Doing this, shading in the pins, helps me to visualise the proportions better. If you can decide that you want a certain size for pins you must then decide whether you want full pin sizes or half pins to the outer edges first.

I think this sketch illustrates how the appearance can be changed by sizing and number options and that is just four options!

On the double dovetail this is easy because the main decision is the size of the pins. On a 3″ section of wood the pin total at 3/8″ will be 1 1/8″. Deduct this from the 3″ and you end up with 1 7/8″ so the dovetail width will be 15/16″. You can always vary the sizing on boxes where the overall height of the box is not intended to fit into an opening as with a drawer. An industry standard in some spheres is to have half pins and full pins. so with our current scenario of 3″ we would have 2 x 3/16″ = 3/8″ plus the full pin of 3/8″ so 3/4″ pin accumulation. This then leaves 2 1/4″ for two tails so 1 1/8″ dovetails. As I said, for me, generally, I simply use 3/8″ equally for all of my pins as my standard size in my more general work. This would be for kitchen drawers, tool boxes and chest. They are beautifully strong and attractive too. For a more refined look I might half that size to 3/16″. For the prissier look I would use my saw kerf alone for sizing pins.

So now we will see that the sizing of the pins gives us the overall deductible distance and what’s left is simply divided by the number of tails we are aiming to have. Larger pins generally give us the smaller tails contrast we aim for. So i the next blog on dovetail layout let’s look at the system that works well that comes from dividing the tail piece into even divisions. We use this all the time to reduce the need for complex calculations and measuring and dividing increments mathematically. It’s a simple process. This video will help you with this better than the thousand words above, perhaps, but the thousand words slow everything down to present bite-sized understandability.

 

10 comments on “Dovetail Sizing—Keep It Simple

  1. The video was very informative, and worth watching. Thanks!

    I would like to know more as to why “fine” pins are so “aesthetically pleasing.” They look awfully fragile to me–are they? Even in the finest furniture, a half-blind, hefty dovetail would exude the quality of strength, and always be welcomed, I would think! However, I have indeed seen examples in 18th and 19th century furniture having mere wisps of pins…

    • I suppose they are a bit like white sugar for the elite classes in days past. They do express refinement and you will find them on even vernacular pieces too. Often carpenters cut both sides of the dovetail from the same initial cut, angling the saw in one rake direction first, and then dropping the saw in back into the same start-kerf and cutting the adjacent one at the opposite angle. This of course is the thinnest pin of all. In strong, close grained woods it is reasonably strong. It’s nice to have a challenge on a fine piece of work from time to time. A bit prissy and showoffish mostly though.

      • I love the look of fine pins, can’t really tell you why I just do. I see it less as a joint and more like a design or pattern. Then when I see alternating sizes of pins it brings it to a new level. Half pins at the ends always make me think of the strength of the joint and I’d prefer full sized pins. Such a helpful post and video thank you Paul!

  2. Our profession has its share of snobs. The greater cause of this is for the work to look hand cut, not with a dovetail bit but a dovetail saw. The quickest way to do this is have pins whose width is so narrow a dovetail bit would not pass through it. Therefore hand cut and more desirable . They are also inherently weak and wimpy, but obviously hand cut so more desirable.
    The most egregious will leave a score line on the outside of the box so the world will know that yes, you laid it out by hand and therefore cut it by hand, so it’s hand cut, more desirable. But you should also know that every craftsman of our trade will cringe when he sees your work.
    I think Paul’s most successful goal has been to reduce the cringe factor by teaching aesthetically pleasing ways to lay out our work. (and never even mention the cringe factor).

  3. I’ve read that small pins allowed the corresponding dovetails to cover more end grain in the thicker parts, thereby reducing seasonal intake of moisture and swelling, or something. Does anyone believe that theory, or does it just spring from the fevered mind of a writer trying to fill space?

    • Not reality really and probably a writer/theorist view too. People have a very distorted perspective about the expansion and contraction of wood. It’s as if they see wood in a drawer side expanding more than the drawer front or that the joints themselves are non-constraining when in fact many joints do constrain wood and prevent movement too. Much more than we think. Personally, reducing the expanse of a dovetail width means it is less likely that the dovetail in its housing will cup away from its seating. That’s why I say keep the dovetails under 1 1/4″. I have seen dovetails wider but less commonly is that so and I think that that is likely because other craftsmen felt the same way.

  4. Hi Paul: I am fairly new and a subscriber, but can cut some decent dovetails. My problem is that I learned to lay out a board using a divider. It takes a bit to get the spacing right and I was wondering if your system of dividing a board using the ruler could equate somehow to using a divider and do the layout somewhat quicker?

    Jay

    • Yes, it’s simple enough. Make the diagonal line edge corner to edge corner to an easily divisible number. Lets say you have a piece of wood 5″ and you want 6 tails. The distance diagonal would best be say 12″. Now set the callipers to 2″ and step off the distance on the line. You can now step off all the two inch points or reset the callipers to the crosshairs square to the edge of the board. This can then be stepped off on the end where the dovetails will be. The points then become the centre of the pins and you follow the same procedure as I used by adding a distance either side of these points to establish the position of the pins which in turn gives you the dovetail positions.

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