This Try Square is a Little Bit of BS


To reward myself for finishing my edit of the translated text of “To Make as Perfectly as Possible: Roubo on Marquetry,” I spent the morning in the shop finishing a try square that had no connection whatsoever to Roubo or the French people.

It’s the small try square from Benjamin Seaton’s famous tool chest that is featured in the must-have book “The Tool Chest of Benjamin Seaton: 2nd Edition” (Tools and Trades History Society).

The first edition was fantastic; the second edition is twice as good. It features lots more data on the tools thanks to the careful measurements and drawings made by Jay Gaynor and Peter Ross at Colonial Williamsburg. Their scholarship pushed this book into one that is rivaled only by “With Hammer in Hand” on early tools. So buy it. Right now.

I bought the second edition the week it was released and have been poring over the drawings for months now (One quibble: The hand-lettered dimensions are too small in places.)

One of the many surprises in these drawings was the detail on the wooden try squares that young Seaton built for his toolkit. The photos make them look like two flat pieces of wood and barely worth note.

But the drawings point out details that made me start building a run of these squares to put to use. Here are some of the details:

1. The blades taper in thickness. They are thickest at the stock (about 1/4”) and taper to .065” slightly at the tip to .16.

2. The blade is joined to the stock with a double tenon. This is a little trickier to make than an open bridle joint.

3. The stock of the square is beveled at the top, bottom and outside edge.

I had milled and mortised about a dozen stocks using wood that was left over from a campaign chest. This morning I discovered that all but four of the stocks had cast horribly. So those wonky bits will become something else.

For kicks, I fooled around with making the blades on the band saw, but found that was a fool’s errand. It was much faster to taper them using a jointer plane and saw the tenons with a tenon saw.

All in all, this square was noticeably more complex to make than the square shown in Roubo.

— Christopher Schwarz

About Lost Art Press

Publisher of woodworking books and videos specializing in hand tool techniques.
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22 Responses to This Try Square is a Little Bit of BS

  1. TJH says:

    And the reasons for all those details? Because he (and you!) could!?


  2. Dave says:

    I am not sure I understand why the blade is tapered from the stock to the tip other than to make it lighter weight, better balanced, etc. In use, doesn’t that slightly tip the stock out of square to the board it is up against? I may be missing something.


    • lostartpress says:


      Actually, the tapered blade is a very good thing. It makes the blade easy to press against irregular work. And when you press the blade flat against the work, the stock of the square contacts the work only along one thin line. This means you are much less likely to encounter debris or dust that will throw off your reading.

      Hope this makes sense.


  3. John Vernier says:

    Whoa there! I just made one of these as well, so when I saw your taper to .065, I did a spit take. Where did you get that!? I just checked the book, and the .065 is on the drawing at the bottom left of the page, which is the iron scribe from the kit, not the squares. Yes, I find the drawings a bit confusing too. The squares’ beams are tapers, but not so much as that. I’m making the set of 3 for my toolbox. I’m letting the longer blades cast right now before i plane them up to final thickness.


    • lostartpress says:

      Yeah, let me check my drawings… Yeah, I picked up the number from the scribe illustration in my haste. My taper goes from 1/4″ at the stock to 5/32″ at the tip. Or .16″. My mistake.


  4. That is indeed a very interesting book, I only got my copy a few weeks ago. If you visit Colonial Williamsburg you can see the reproduction chest in the cabinet shop and a less ornate version in the Joiner’s shop.


  5. Don Braboy says:

    I’ll have to try one of these as well! I’ve been reading your blog for a few weeks now after seeing your Anarchist tool chest video. My great grandfather’s old tool chest was passed down to me a few years ago, and your writing, videos and links have inspired me to search out its history even more. I’ve used some of the old tools occasionally, but two weeks ago, I cleaned out the old chest, and I’ve since been working nearly exclusively with tools from it plus some of my own. I just finished a nice white oak mallet to place in the chest. My intention is to complete the tool set with period tools – and use them in my work of course. Thanks for sharing your experiences!


  6. luce32 says:

    I assume the word “cast”, in this contex, means to stabilize? I have never heard it used in woodworking but I’m new to this site.


    • lostartpress says:

      Hey Rick,

      In traditional woodworking lingo, “cast” means to “warp.” Sometimes I get so entrenched in my old books that I start writing and talking like them. Apologies.


  7. In making the blades do you taper them after they “cast”? I would think that tapering the blade would keep it from warping since it would expose more end grain over the entire length allowing a more even exchange of moisture. Am I way off base or is it the NyQuil kicking in?


    • lostartpress says:


      Exposing the end grain will indeed help the parts remain more true during the seasonal changes.

      My problem was I milled them when they were not quite at equilibrium. As they reached equilibrium, many of the stocks warped.

      Luckily, the blades were still a tad over-thick. So I milled those down to final size with no problems.


  8. Sawdust maker says:

    I have only one question. Why would any person taper the blade of a try square? It seems to me that tapering it would weaken it and make in more susceptible to breakage.


    • lostartpress says:


      A tapered blade has advantages. When you press the stock against an edge and lay the blade flat on your work, then the stock is contacting the work only along one line. There’s less of a tendency for debris to mar the contact between the stock and work.

      I’ve seen this characteristic on several old squares. All three of Seaton’s squares were constructed this way.


    • Chuck N says:

      Half the fun here is for several of us to make one and try it.
      Let’s not let Chris hav all the fun of discovery.

      I’ll just take one of my existing wooden try squares, taper its blade, and give it a go.


  9. Larry Chenoweth says:

    In the past I remember you commenting on using some architectural or engineer rulers that were tapered on each side and flat in the middle. You liked them but did not like the way the edges did not contact the surface. Someone with some drafting background said that was so felt tip pens could be used against the ruler. This allows the draftsman to tip it flat down to the work to see his measurements right at the paper allowing for accurate measuring and keeping it up off the paper when he is ready to mark along the side. I own some of the rulers and straight edges made by Woodpeckers. Some have flat sides and some have tapered sides. The ones that have tapered sides with the ruler measurements going all the way to the edge allow me to mark my work much more accurately as I do not have the full thickness of the blade that I must sight down to accurately mark. With this in mind maybe the blades of the squares were supposed to end up with some measuring graduations on them to use but did not get added . This would surely explain wanting the blade to be tapered. Just a thought.


  10. I have to make a few of these thanks , interesting . I trained many moons ago with German Master joiners . They said- Cast- often aka to twist and or warp. was refreshing to see you use that term.
    looks like a good teaching project for some of the kids I teach sometimes .



  11. Paul says:

    My old drafting straight frets & squares have tapers and or rebates, any one who had to do finals(in engineering) in ink will remember (pre pilot and felt tips)


  12. Paul says:

    Oops, maybe edges will make more sense!


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