The Graphic Rule

This excerpt from our latest book, “From Truths to Tools,” speaks to a rather esoteric, but highly useful, rule for use with scaled drawings:

Graphic Rule

Here’s a typical, traditionally drawn small boat plan:

boat plan graphic rule

To find the dimension of any particular part of the boat, we simply set the divider to the part – here the cap on the centerboard trunk:

IMG_20180419_104259

Then we transfer the dimension (what the Greeks called, more precisely, a “magnitude”) to the graphic rule…

IMG_20180419_104312

…and read the numerical distance of 3′, 6″. This technique eliminates the need for an awkward and hard-to-read scaled ruler and, furthermore, works no matter what scale the drawing is made to.

— Jim Tolpin, byhandandeye.com

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9 Responses to The Graphic Rule

  1. Donald Kreher says:

    I have now finished reading “Truth to tools” and will admit to learning a few things. In particular I do like the “graphic rule” and the use of arcs to copy the dimensions of a center board. Do you have a recommendation for a good “text book” on practical drafting for the woodworker without CAD?

    • ctdahle says:

      Heya Donald,

      Until I read By Hand and Eye, and By Hound and Eye, my go to book was Architectural Drafting and Light Construction by Edward J. Mueller. It contains a bunch of stuff that is nice for a woodworker to know, but not necessary, and it’s not much of a “step by step” “how to make drawings” sort of book. Still, any edition in good readable shape is a good resource.

      But having Hand and Eye, and especially Hound and Eye on my shelf really changed the way I think about drawing, whether it’s furniture or cabinets or a mountain cabin or the design for a media room. Those two books, in my opinion, contain about 90% of what a woodworker needs to know about drafting, and while I don’t use them with my students, they inform what I am trying to teach middle-schoolers when I teach my unit on CADD.

      If you need a good primer on the basics of T-Square, drafting board, triangle, using an engineers or architect’s scale and so-forth, there are a bunch of old introductory level books out there that cover the raw skills. Search used books for titles like “Drafting for Beginners” or “Boy’s First Book of Mechanical Drawing”. These were thin little books for kids in the industrial arts classes of another generation and you can find them for a buck or two. Or try the central library of a big city…an adult should be able to work out most of the basic skills in a week or two of concentrated study.

  2. Donald Kreher says:

    Thank you for your reply.

    I downloaded the free Google book ” Essentials of Drafting, by Carl L. Stevens”, but will look for books with the search you suggest. I may look at Hand and Eye, and Hound and Eye too. Incidentally I do have a Ph.D.s in Math and Computer Science, I have taught computer science courses in computer graphics and geometric modeling and also mathematics courses in abstract algebra where once I went through the mathematics of what is constructible by straightedge and compass.So if I must use or develope a cad system I could do so. I am just interested in being educated in the old methods of drafting. I think it would be rewarding.

    • jenohdit says:

      Any freshman engineering fundamentals textbook will have the basics and can be had for less than dollar if you look in the right places.

      In my experience older books are more likely to cover things like pinning the paper to the board and sharpening pencils properly if you need that. I have a copy of Architectural Drafting and Light Construction as mentioned above and it’s ok but I’d recommend one of Francis D.K Chings books instead or in addition.

      You really just need to know a handful of basics and then get used to drawing by doing it badly for while. With your math background, you in particular might have fun with E. H. Lockwoods “A Book of Curves” for that although it has nothing to do with representing physical objects.

    • jenohdit says:

      Another good book I just pulled off my shelf is “Design Graphics” by C. Leslie Martin it’s much more devoted to drawing without adding all of the mid-20th century home construction details that Architectural Drafting and Light Construction adds. It goes way into detail covering subjects like accurately drawing shadows and the basics of presentation and materials like tempera, pen and ink, etc.

      Copying drawings you find is a great way to learn and that has always been the foundation of training. Carlyle Lynch was a first rate furniture draftsman. Just like you can learn from drawing the classical orders, you can learn far more than you might imagine from simply copying one of his drawings as perfectly as you can at some predetermined scale.

    • ctdahle says:

      I envy you your math and computer skills. I squandered my grad school years on…something less interesting*. But let me say this, I was not in any way discounting your intellect when I suggested the beginning drafting titles. The little textbooks of tradecraft for HS students of the 1930s-50s, or earlier, are far more thorough in their brevity than the dumbed down, sugar coated educational puree we often are stuck with today. Even the Edward Mueller book tries a bit too hard to convince kids that construction and architecture might be fun careers.

      Anyway, if you learned your Euclid with dividers and a straightedge, then you will definitely enjoy playing with a T-square and drawing board, and find it no less rewarding than making those “gossamer shavings” with a smoothing plane.

      In regard to Mr. Tolpin’s books, Hand and Eye made me rethink what I was trying to teach. Hound and Eye made me rethink how I teach it (I teach a set of industrial arts classes styled “STEM Explorations”, and run a gifted/talented program). Now I am looking forward to further enlightenment from Truths to Tools and am looking forward to having my present ideas tweaked a bit more.

      I only got around to ordering “Truths to Tools” this morning…I promised my wife I wouldn’t buy any more LAP books until I’d finished building her boarded book case (Chapter 18 in The Anarchist’s Design Book)…happily finished last night. I confess much use of the table saw and jointer, and I did draw the bookcase in SketchUp before I made any sawdust. In my defense however, this was because I really needed to teach myself a bit more about CADD. CADD does make sense in a world where modern design clients need frequent and rapid revisions of evolving design. But it’s overkill when you just need a shop drawing of a cabriole leg or a Queen Anne writing table. Unless I have some particularly difficult joinery to work out, I stick with the hand made drawing.

      I’m glad jenohidt mentioned the Francis DK Ching books. I have several and can get lost in them for hours just because the drawings are all so cool. My problem is I am like a kid in a candy store with all this stuff. Whether it’s trying out historical skills and tools as they are documented and resurrected by the great folks at Lost Art Press, or figuring out how to configure I2C devices to talk to a Raspberry Pi, I just keep finding more stuff I wanna learn. Sounds like you are similarly curious. So, Cheers!

  3. w.s.gilliam says:

    I must now have these books!

  4. Coop Janitor says:

    A good companion book for the Toplin, Walker books is ‘Thinking with a Pencil’ by Henning Nelms. Not art, not drafting, not design.. Graphs, sketches, whatever – getting ideas on to paper. It is back in print (so says Amazon). Got my copy back in the early eighties.

  5. Darrell Urbien says:

    When I taught Drafting, I was a big fan of the textbook “Basic Technical Drawing” from McGraw Hill Publishing. It was more for the machine trades but it had interesting stuff on how to do developments, cams, auxiliary projections, intersections, etc. all by hand. Nowadays these things can be done at the push of a button, but it’s still neat to see how it works graphically. The book also covers how to clearly and accurately dimension an object, which today seems a lost art in itself. There are bigger, more comprehensive books out there, but this one seemed less daunting to most of the students. I believe the book is now out of print, but search used sources; you could probably get one for very little money.

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