Exeter Hammers, ‘Principles of Design’ & Dados

By the end of this week (assuming no more disasters), we should have a clutch of our new Exeter-pattern Furniture-maker’s Hammers for sale, as well as – finally! – “Principles of Design” (we thought we’d have it in June, but we’ve been bedeviled by cover problems at the bindery).

“Principles of Design” is our title for a reprint of “Industrial Arts Design” by William H. Varnum. It was first published in 1916 to help train industrial arts instructors to teach design. The book deals with furniture, ceramics and metalwork. All three crafts are regulated by the same rules laid out by Varnum in absolutely crystal-clear detail.

If you’ve been building or studying furniture for a while, there are some of these rules you know by instinct but not by conscious thought. By laying out his simple principles, Varnum makes the basic design process rational and not regulated by the dark arts of inspiration or creativity.

In many ways, Varnum’s rules prepare you for creative leaps. Here, he says, are the rules established by hundreds of years of furniture making. You can work within this comfortable envelope, or you can deliberately step outside his guidelines.

His approach is compatible with George Walker and Jim Tolpin’s writings on design. In fact, many of their ideas from “By Hand & Eye” (such as whole-number ratios) integrate easily with Varnum.

So keep an eye out for those two new offerings later this week.

And keep an eye out in early November (barring printer delays) for my book, “Dutch Tool Chests.” It will be available directly from us (yes, we will have signed copies), and we hope from our retail partners (as always, it is up to them whether or not to carry a book). In the meantime, here’s a taste of what’s inside, excerpted from Chapter 5: Dados. Below is my favorite way to cut them, though I offer other options in the book, including some that – GASP! – use electricity.

– Fitz

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Saw With a Fence
My preferred way to cut a dado is with a crosscut saw, followed by a chisel and a router plane to clean things up. With just a little experience, it’s easy to nibble your way back on the layout line with a crosscut saw to cut a shallow kerf. Once the kerf spans the board, you can use that kerf to guide the tool as you saw more aggressively down to the baseline.

If this is your first dado, or if you’re not yet comfortable sawing to a line, you can use a fence to help guide you. (Again, one of the skids can come in handy for this purpose – or any other piece with a straight edge that is no longer than the width of the side; otherwise, your saw handle might run into it.)

Clamp the fence down along your layout line (clamping the workpiece down simultaneously), with the waste to the inside. And here is why I like a 0.5mm pencil: if you use a fat pencil, the range of where across the line’s width to clamp is too great. A 0.5mm pencil is the perfect size for covering about half the line, leaving just enough of it to show along the edge of the fence. (If you can’t see the line, how do you know you’re sawing the line?) Make sure to arrange the clamps or holdfasts so that they aren’t in the path of your saw. Or your knuckles.

Now grab your crosscut saw (backsaw or handsaw – it doesn’t matter much when you have a fence) and push the plate against the fence with a flat-sided block of wood held in your off-hand. If the block of wood is long enough, you can simply hold it in place to help keep the plate at 90° to the workpiece as you saw. With a shorter piece, it helps to move the block in tandem with the sawplate. Saw down to your baseline – and check to make sure you’ve hit it on the far side, too. Then lift the saw at a slight angle and make a few short cuts to deepen the center of the kerf. It’s possible you’re sawing below the baseline there … but more likely you’re removing waste in the middle that you missed. Either way, you’re making the waste easier to remove.

Do not move the fence. I repeat: Do NOT move the fence.

Grab your shelf board and match up the marriage marks on the shelf to the mark on the side piece. (Both should be on the front edge and facing up.)

Press the shelf to the fence – on the waste side of course – and pencil a mark at the front and back edge. If the board is rocking at all, press it tight at one edge and make the mark, then rock it to press tight at the other edge and make a mark.

Now you can remove the fence.

To cut the second dado wall, you’ll need to approach the work from the other side to keep your hands in the right place for ease of sawing. So if you can’t access your bench from both sides, turn the workpiece 180° before clamping the fence in place to the lines. As before, cover as much as possible of the lines, leaving just a hairsbreadth showing in the waste.

Double-check that the waste is to the inside of the fence, and that your clamps or holdfasts are far enough to the side so as not to impede your sawing. Now triple check. All good? OK – saw as before.

If you’re making a two-bay chest, go ahead and saw the walls of the second dado the same way.
If you used the method above, I’ll bet after two cuts you’re already sick of that fence. And if you’ve made four cuts (for two dados), you’re definitely sick of that fence.

Saw Faster (No Fence)
Now, you might be worried about messing things up without the training wheels of a fence – but if you’ve cut a dado or two, trust me: You’re ready to just saw. And (most) mistakes can be fixed.

Start with just the end of the saw – no more than an inch or two – on your layout line and take small bites as you work back along the line, blowing away the dust as you go so that you can see the line. Continue to gently nibble and blow for good results.

Once you’ve cut a shallow kerf across the entire board, drop the sawplate into the kerf and use it to guide the tool as you saw more aggressively down to the baseline. Do your best to keep the saw perpendicular to the work.

Once you become comfortable with that method, you can go faster still by starting the cut the same way as above, but lowering the saw into the kerf and taking longer and longer strokes to deepen the cut all the way across, using your first, nibbled kerf to guide you. (You’ll reach the baseline more quickly at the far side, so adjust your stroke as required to reach full depth all the way across.)

Note that sawing without a fence – and doing it aggressively – is easier with a backsaw because the back, or spine, help to keep the cut straight. But most backsaws have smaller teeth than a handsaw (a saw without a spine), so if you’re feeling both brave and in a hurry, grab a crosscut handsaw.

Now let’s say you started sawing without the training wheels. How, then, to mark the second wall of the dado? You could measure and mark, but that’s more likely to introduce error than simply holding the shelf in place on the waste side of the kerf, and marking at each edge of the board. Align the shelf so it just covers the full width of the kerf (you’ll be able to see it on the edge). Align it at the other side to make the mark there (just in case the shelf is not dead flat). Then use a pencil against a combination square to connect those lines.

Saw again – this time cheating just a hair toward the waste on the inside of your line. This will likely result in a dado that is too tight – but there’s a fast an easy “fix” that all but guarantees a nice, tight dado. I almost always shoot for too tight.

With all the kerfs cut on one side, you can show it to the other side and use a marking knife in the kerf to transfer the location to the interior of the second side (check those marriage marks!). If you marked the layout on both at the same time, check that your cuts on the first side match up to the lines on the second side. If not, erase the layout lines, transfer the new location and re-mark.

I prefer to put the two front edges together as I do the above, simply because that means the marriage marks are touching, and it’s easy to tell you have things facing the right way (at least, until you butt the boards together and can no longer see the marks).

Now saw the dado walls on the second side, same as before (or, if you used a fence on the first side, try it without now!).

Bash Out the Waste
With the walls cut, we’re ready to remove the waste between them, down the baseline.

Grab the widest chisel you have that will fit between the dado walls. (A 3/4″ chisel is in theory the perfect size; in reality, you might need a narrower chisel. Especially if you cheated the cut toward the waste maybe a little too much.)

Hold the chisel flat to the work (bevel up), about halfway or a little farther down into the waste, and knock out as much as you can across the width. Repeat, this time just above the baseline. (You might be able to get it all out in one go, depending on the wood species, dado depth and your tolerance for fear.)

Flip the piece and work in from the other edge. You might be able to reach the middle with your chisel bevel up for all the work. But if you can’t, flip the chisel bevel down to remove the remaining waste in the middle. Bevel down is faster, but the tool wants to dive in more deeply in that orientation, so stay alert.

Get close to the baseline with the chisel. Or, finish the dado with chisel cuts if you like, taking small bites at full depth for a clean dado floor. But it’s easier to get a nice, smooth bottom by using a router plane.
Use the baseline to set the router plane blade to the final dado depth. Make sure there are no chips under the plane’s sole, then simply zip out the remaining waste, working in from both sides so you don’t blowout as you exit the cut (blowout is never pretty).

Why not use the router plane to remove all the waste, lowering the blade with each pass? You can, but that’s a lot slower, and you miss out on mallet fun. Also, the router plane blade is more fussy to sharpen than a chisel – so I’d rather my chisel take the brunt of the waste removal.

— Megan Fitzpatrick