Chris Schwarz's Blog

Roy Underhill’s Dovetails

dovetails

Even though I am 100-percent confident in my ability to join two boards together using the tail-of-the-bird joint, I am always riveted when I get to see how other accomplished woodworkers go about the task.

In fact, when I watch others work, I never fail to pick up some important details.

On Saturday at our Woodworking in America conference I got to watch Roy Underhill from “The Woodwright’s Shop” television show cut some dovetails and discuss his approach, which is planted in history and practical experience. So here it goes.

Underhill began by asking the audience to tell him the rules of cutting dovetails, and he got a big long list of everything from the degree of the slope to the layout to the order of operations. Then he showed us a pre-Civil War tool chest , a beautiful dovetailed tool chest , that violated almost all of those rules. And that’s where he began discussing his approach to through-dovetails.

roy underhill's dovetails

Layout
Underhill likes to cut the tails first when he can, and he strikes his baselines with a cutting gauge set to the thickness of the work plus 1/32nd.

Then he lays out the tails by first marking the half pins at the edges of the tail board. How wide should the base of each half pin be? One-half your stock thickness. Underhill was joining 3/4″-thick material, so the half pins were 3/8″. He laid those out with a 3/8″-wide chisel. This measurement , 3/8″ in this case , is also the space between the each tail at the baseline.

How wide are the tails themselves? Underhill uses twice the thickness of the material , or 1-1/2″ wide in this case. Then he lays out the tails using a ruler that he lays diagonally on the board. He marks out the centerlines where the holes for the pins should go, then strikes out the 3/8″ dimension by eyeballing the 3/8″ chisel on the centerline. Then pounding it with his hand.

Slope Angle
Underhill isn’t much of a believer in using certain slope angles. He goes by eye and scribes them with a sharp pencil and a bevel gauge.

“Oh, that looks good,” he said. Then he shows the layout to the audience and said that if it looked right it was right.

“Throw away your dovetail marker,” he said. “Just do it. Throw it away.” Then he cuts the tails but does not remove the waste between them.

Transfer the Marks. No Knife
To transfer the shape of the tails onto the pin board, Underhill uses his dovetail saw. He places his tail board on top of his pin board (which is clamped in a vise). And then places the dovetail saw in the kerf and scores the end grain of the pin board. It’s a light mark. Too deep and your saw will jump into the kerf when you are sawing out the pins. You actually want to saw in the waste next to this line.

Then he draws the shape of his pins on the pin board and cuts them with a dovetail saw. To remove the waste between the pins, Underhill uses a coping saw, which he lubricates with mutton tallow.

Chiseling Out
When he chisels out the remaining waste he intentionally leaves a hump in the floors between the pins. Then the clamps the board upright in a face vise to pare out the remaining hump.

To remove the waste left between the tails, Underhill uses two chisels. He used a 3/8″ chisel at the baseline and a 1/4″ above the baseline. He beavered out a “V” using the two chisels (I’ve never seen this technique before).

Then he asked the audience to please not ask him about gluing dovetails.

“I’m a TV woodworker,” he said. “So I can’t glue anything together on camera because we might have to knock it apart and do it again.”

The message from Underhill (or St. Roy to you and me) is this: Dovetails were made in a wide variety of ways by skilled craftsmen. If you are building an original design, make dovetails that look good to your eye. If you are going to copy a piece, use their layout.

“We had a saying at Colonial Williamsburg,” Underhill said. “It was: ‘Stop trying to improve the 18th century.'”

And if the above rational discussion doesn’t settle the arguments about dovetails, I recommend you do what Underhill did later that evening: Arm wrestle the managing editor who prefers pins-first instead of tails-first.

– Christopher Schwarz

19 thoughts on “Roy Underhill’s Dovetails

  1. Steve Branam

    I just watched episode 2613 "The Dovetail Variations" at http://www.pbs.org/woodwrightsshop/schedule/26season_video.html. It compresses an enormous amount of knowledge and skill building into less than 20 minutes. My favorite was the little knockdown bench made with tapered sliding dovetails. There is also the rising dovetail mentioned in Chris Schwarz’ downloadable appendix to "Workbenches" at http://www.lostartpress.com/ProductDetails.asp?ProductCode=BK-WB. Plus another of the 23 known woodworking puns, "with mallets toward none".

  2. Bjenk

    I first learned Dovetails with Roy’s books.

    Now that you mentioned a Pre-Civil War tool chest… Is there any way to see it? A photo? You can’t just mention it and expect us to let this pass. Is there any way to see it for those of us unlucky souls that couldn’t make it to the conference this year?

  3. John Grossbohlin

    I’ve seen a lot of Roy’s work first hand (I worked at Williamsburg in the mid-80s) and have had the opportunity to spend time with him outside of CW over the years. His "one deep breath" filming of The Woodwright’s Shop doesn’t allow for the fineness of work that we "modern" woodworkers seem to demand. This because he is trying to convey a lot of information in very little time… I’ve seen some very fine work of his and particularly like his Neander vs. Normite chess set. Even in it’s "shop worn" condition (from being pawed by power tool heathens) you can see the fine work that he is capable of producing. RE the show, if you pay attention to his processes rather than nit pick his rushed results there is a lot of very good information to be gained.

  4. Andy

    Anyone who doesn’t think Roy Underhill is a skilled woodworker is mistaken.

    If you watch a few of his Woodwright’s Shop episodes, it’s apparent that he is a skilled craftsman with deep understanding of the evolution and use of hand tools.

    Yes, you will see some occasional misteps, but they are minor errors of execution, not of technique. Unlike most how-to shows, Roy’s show is seemingly recorded in one continuous take, with minor, if any, post editing.

    As any woodworker knows, the best position to perform an operation, such as cutting a dovetail, is also precisely the position the camera needs to be in to capture the operation. All the more reason to applaud what he can accomplish in less than one-half hour under less than ideal conditions.

    My thanks to Roy for all he does to disseminate traditional woodworking techniques.

  5. Nathan Beal

    Auguste,
    I would love to see you post some of your work and techniques somewhere. I have seen you post here quite often, but I have rarely read anything constructive from you. If you have something practical to add to the world of woodworking you should get it out there. With all your posts over the last year you must have loads of experience you can offer to those of us who are trying to improve our own skills.

  6. Jim Brown

    Roy (or St. Roy) is a master craftsmen in the truest sense of the term. I recall he was the "key-note speaker" at my son’s Cub Scout Blue and Gold dinner a few years ago. To have the chance to hear his wisdom as it was told to a group of elementary school aged boys was priceless. There were more Ooh’s and Aah’s than you could shake a stick at from both the Scouts and parents.

  7. Tom Iovino

    Roy was masterful…. he clearly explained ‘the rules’, then showed how dogmatic we have become and showed how you can break them and come up with an awesome design!

    Now, to get MUCH more practice on my handcutting technique…

    Jay – They run on the PBS stations here in the Tampa market… you may want to check with your local PBS folks…

  8. Herb Hausmann

    love your magazine, have every issue. Looking forward to the building of the shaker item from Whitewater as I previously lived near there. Also, i know ther person-Rick Shambo- who ripped out the waistcoat and peg rail from the meeting house.

  9. Steve Hilton

    I love original or old technique more than the new stuff. I am impressed with Roy’s style and I will try his way on the next set of tails I cut, unless of course he looses hit arm-wrestling match with Megan.

    Steve Hilton
    Prescott, Arkansas

  10. Kevin Fellows

    Hi Chris

    Thanks for this very informative article. One piece I didn’t get though. Could you please expand on this sentence: ‘He beavered out a "V" using the two chisels’.

    Many thanks

    Kevin

  11. Ric Washburn

    When joining two boards of differing thicknesses, I would use 1/2 the thickness of the thicker board for the width of the pins at the base line.

    Using the example in Ian’s question above the tail board is 1/2" thick and the pin board is 3/4" thick. If you make the pins 1/4" thick (1/2 the tail board thickness), with much of an angle at all to the pins, in 3/4" stock you are going to have very little wood in the pins giving you a weaker joint (this could be helped by making more pins, but that might look odd).

    For example, if you used a 6:1 ratio (makes it real easy to do the math: 3/4" / 6 = 1/8") the pin would narrow by 1/8" on each side. So with a 1/4" wide base, the half pins would be 1/8" wide at the top (I do notice that Roy’s 1/2 pins are not really 1/2 the width of his full pins) and the full pins would be 0" wide at the top. I think that the space between the tails for the full pins might be a bit hard to cut!

    A 12:1 ratio will leave you full pins 1/16" wide at the top, but that is a bit flat for a lot of folks, and in less dense woods will be more prone to loosening over time, especially with multiple dry fits. (I like a 9:1, but that 1/32" wide gap to cut the tails through could be a challange to keep clean.)

    Using a base width of 3/8" for the pins (1/2 pin board thickness) and the 6:1 ratio leaves you with pins 1/8" wide at the top, making the tails much easier to cut.

    Applying this to half blinds, I would follow the same logic, the width of the base of the pins would be 1/2 the lickness of the depth of the tail. Or to make it a little clearer, using a 1/8" blind in a 3/4" pin board the tails will be 5/8" deep so the pins would be 5/16" wide at the base.

    If you were going to leave the tails and pins proud of the surface by 1/8", with the 3/4" pin board the base of the pins would be 7/16" (3/4" + 1/8" gives you tales that are 7/8" deep, 1/2 of that give you 7/16").

    What you choose to use for the slope of the sides of your dovetails when using pins this delicate (especially in thicker stock) will be mostly determined by how small of an opening you can keep clean as you cut the tails. The smaller the pins, the more obvious variations in their sizes become.

  12. Eric

    If Saint Roy says tails first, then woe the blasphemer who would suggest pins first!
    He can cut better joints in his sleep then I could if you gave me a week!

    Thanks Chris.
    Great article!

  13. Adrian

    The talk of half tails in the layout section confused me. Did you mean half PIN in the layout section?

  14. Christopher Schwarz

    Ian,

    You’ll have to ask Roy on that. He covered half-blinds, but didn’t cover unequal thicknesses. I imagine he would say: "If it looks right it is right."

    Chris

  15. Ian Wigle

    Well if that’s what St. Roy says, then it is holy writ.
    Thanks Chris. One question though. It may be a bit too early in the day for me, but I’m not quite clear on how Roy would approach a dovetail in unequal boards. For example a 3/4" drawer front with 1/2" sides. (Let’s ignore half-blind issues for the moment.) When cutting the tails in the 3/4" drawer front, does he make the space for the pin 3/8" at the bottom, or 1/4"? And similarly, does the thickness of the pin board affect the spacing of the pins, or is it the thickness of the tail board?

    Thanks,
    Ian

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