Another Roubo with shelf: I mostly plane at this bench so I keep all my go-to bench planes on the shelf. Notice I over-built the frame to add enough mass to fully eliminate any motion under planing action. The bench sits a bit away from the wall to provide wall space to store my handsaws.
Here’s an old school carpenter’s (or landscaper’s) method of laying out a line, such as a foundation form or a hedge row, to a specified angle. The tools needed are simple, primitive even: A length of rope marked at a certain distance and a 10′ pole marked in 1′ increments (i.e. the once ubiquitous carpenter’s 1o’ pole). Or you can join the 20th century and use a tape measure.
Let’s jump right in and lay out an 8° angle from a baseline. The drawing above is pretty self explanatory, but I’ll explain it anyway in my hopefully not too pedantic step-by-step fashion:
Step 1: Establish the baseline (via a stretched string) and set a pin (a sharpened stick works) at the focal point where the angle will converge.
Step 2: Make a loop at the end of a non-stretchable rope (i.e. avoid nylon) and run it out along the baseline from the base pin. Measure out 57′ 2-1/2″ from the pin along the rope and make a mark with a Sharpie or tie on a piece of string. Also, set a pin at the baseline at that distance.
Step 3: Now arc the rope away from the baseline in the direction you want to lay out the angle.
Step 4: Set the base of the 10′ pole at the baseline pin and orient it to the rope. When the 8′ mark on the pole passes over the mark on the rope then the angle to the baseline is (drum roll) 8°.
So how does this work you might ask? As my friend Joe Youcha of buildingtoteach.com explained to me: “The answer is buried in the math we were all injected with in grammar school.” We were all told about the “transcendental number” called “pi” which when inputted into your calculator would provide you with either the circumference of a circle based on its diameter or vice versa.
Artisans of antiquity, however, had no knowledge of the decimal number pi. In fact, decimal numbers in general had not been described in detail in the Western world until the late 1500s by the mathematician Simon Stevin. But artisans did have an excellent working relationship with the straightforward (non-cendental?) proportional ratio system. In the case of the relationship of the diameter of a circle with its circumference, they would just step out the diameter into seven segments and know that 22 of those segments would, to a high level of accuracy, give them the length of the circumference. Good enough for government work (such as the Parthenon) as they say.
Because we apparently need to work with degrees (probably because the architect speced out the angle in degrees instead of the length of a chord as they would have in antiquity), we would need to know what number of segments the diameter would be if the circumference were stepped out to 360 segments. That number is, of course, an arbitrary but widely accepted convention since Babylonian times as a convenient way to divvy up a circle. We like it as it can be evenly divided by so many whole number divisions – though for a time Europeans were quite fond of 400 degrees.
But I digress; back to how it works: If you go to the trouble of physically stepping out along the circumference of a circle with dividers, you’ll discover that when 360 segments do the trick, 114 and 5/12ths of another segment will define the diameter. Of course, using al-Jabr (given to us by the Islamic mathematicians), we can quickly solve for this result using an algebraic equation to solve for an unknown.
For this purpose we’ll use half of the diameter segments – fifty seven and two and one half twelfths – to lay out the radius length on the rope. The bottom line: We find that a radius of 57 feet, 2-1/2″ produces a circumference length of 360 feet. So for every foot we swing the arc, we produce an angle of 1°.
The Romans used the square to layout the ubiquitous half-circle arc flutes along the length of their temple columns. You can too: Just set alignment pins at the start and stop points; hold the square against the pins; hold your marker at the apex of the square; and scribe away!
This chest is a close reproduction of a traditional joiner’s tool chest. Chris designed the chest and constructed the box portion during a course he taught with us several years ago. I (Jim Tolpin) finished it by building the lid and sliding till and applying the traditional milk paint. The hand grips (traditional sailor’s beckets of rope and leather) were made and donated by Keith Mitchell – a boatbuilder currently in Vermont. (You can follow Keith on his instagram feed @shipwrightskills). The chest is signed by Chris and me on the underside of the lid.
The box and lid are made from clear poplar boards. The box, the wrap-around skirt boards and the till’s corner joints are dovetailed and glued with hide glue. The bottom boards are set into rabbets and nailed in place with traditional cut nails. The lid’s frame is mortise and tenon, drawbore pinned with hewn, air-dried white oak. Chris and I did the work with hand tools beyond the initial surfacing of the stock to dimension. Dimensions are 20″ wide by 16″ high by 40″ long.
About the finish: Traditionally, these tool chests were always painted to protect the wood from moisture because they might occasionally be exposed to outside conditions. I went with three coats of black followed by two coats of red to create an “oxblood” hue. As you probably know, milk paint is one of the most durable paints available. I applied several coats of linseed/tung oil to build a sheen and to provide additional protection.
All the proceeds of this sale will go to the Port Townsend School of Woodworking youth-in-woodworking scholarship fund. A portion of the cost of this chest is tax deductible as the school is a 501 (C) (3) non-profit educational institution. To purchase, go to the auction site here on ebay.
We (and our kids) were all inoculated with enough Geometry during middle school to “know” the Pythagorean theorem. You know, the one that enables us to rattle off: “A squared plus B squared equals C squared.” But that particular manifestation of the underlying geometric truth of our particular universe isn’t limited to squares. In the above drawing, we have three hexagons built upon the three legs (labeled A, B and C) of a right triangle. Just like squares, if you add the area of the two little shapes they will equal the area of the biggest one. In other words: A hexagoned plus B hexagoned equals C hexagoned. This works for all similarly shaped polygons by the way.
Want the “proof?” All you need is a couple sticks and a bit of string as in the photo below. Have your 4-year-old lend you a hand…she’ll immediately intuit what an equation is really all about! (No, this is not your rigorous algebraic proof, or even a Euclidean logic proof…Instead it’s what me bandmates used to call: “Good enough for rock and roll.”)