I like hanging out with woodworkers, yet a few topics are surefire argument starters. Sharpening is one of those topics, and hand tools versus power tools is another. Yet the argument for using the Imperial measuring system vs. the metric system might just win the prize for generating the most stubbornness.
It’s a fool’s errand to go into the pros and cons of each system so I’ll cut to the chase: both systems can be a real hindrance to developing your design sense. Measurements transferred from a tape measure or ruler can convey important information needed to define and build a project, but they offer little or no help when it comes to proportions. Achieving proportional harmony is one of the key skills of furniture design, and numerical measurements shed no light in that area and can even obscure the proportional relationships in a design.
Further Reading: Not a Life-Hack: The Importance of Geometry for Woodworkers
I say this after spending a lifetime building things from wood and metal and relying on my measuring tools. I finally came to the conclusion that a ruler is a dead thing when it comes to understanding proportions. Here’s an example of why proportions are so important to a design:
A few years ago I visited a construction site near my house and watched as luxury condos went up (at least that’s what the sign said). Then one day I drove by and saw this view of one of the buildings. This is what you could see from the road and was the first impression after going through the gated entrance.
I had to take a picture of what I call a mouse entry. To my eye, the diminutive door at the bottom of the space reminds me of a tiny hole a mouse might gnaw into the base of a wall. This door is completely out of proportion with the space around it. I’d venture to guess that anyone trying to use that door in the wee hours of the morning would get a feeling of exposure and vulnerability.
Pre-Industrial Rulers Provide a Clue
One of the experiences that changed my reliance on rulers and tape measures was finding user-made tools from the pre-industrial era. We often think of this time as the golden age of cabinetmaking, when artisans worked to a high level of precision and had an eye for proportions. Often these rulers were crudely marked out in coarse increments and begged the question: How could an artisan build precise furniture with such lousy rulers?
The answer I’m driven to is that rulers then were used differently than they are today. Rulers were used to get in the ballpark; a rough tool was all that was needed. They had other tools and methods to measure and execute precise joinery.
Dividers were used to mark important joinery locations and at the same time used to step off proportions that would make the design sing. Tiny pinpricks left from divider points left a physical mark to register a knife for cutting layout lines to be followed by a saw or chisel. These simple tools take advantage of the built-in accuracy of the toolset. A line executed by a sharp marking knife is precise and makes a perfect guide to register a chisel. Rulers couldn’t add to this level of accuracy but instead added the risk of making a math mistake.
These artisans understood something about proportions that’s often clouded by our dependence on numeric measurements. Dimensions, whether made using the Imperial or metric system always relate back to an external standard. An inch is just 1/12 of a foot, which in turn is a portion of a yard, just as a centimeter relates to a meter, an external standard. I’ll grant there’s pure genius in standardizing our measurements. It’s a key part of industrial manufacturing and commerce and we’d be shipwrecked without it.
It’s just that to understand proportions and create harmony in a design, we need a way to visualize parts internally, one with another. If a drawing called for a 5/8″ high molding to cap off a bracket foot that’s 21/2″ high (or 1.6cm for the molding and 6.35cm for the bracket), you might be able to guess in your mind the sizes of the two parts. But would you be instantly aware that the molding is 1/4 the height of the foot and linked proportionally? Our inch fractions actually hide that important proportional relationship rather than highlight it.
The second eye-opener that helped me understand proportions was the odd scales that peppered early furniture drawings in historical design books. Those proportional scales aren’t some obsolete relic but instead a key to gaining a clear grasp of how the proportions are linked together in a design.
The first thing to understand is that these scales aren’t connected to any sort of external standard like an inch or foot. The sole purpose of these scales is to show the internal proportional relationships that tie the design together. They don’t tell us anything exactly about the numerical measurement of a piece but they do point out clearly how the internal proportions are linked.
If you don’t get anything else from this article, understand that when you see a proportional scale on a drawing it’s revealing the thought process that ties the design together. It usually spans two parts and lets you clearly see that they’re linked in harmony. I can’t emphasize this enough. It’s actually more important to know which parts are linked together than the specific proportional ratio that binds them. Perhaps this is the greatest lesson these proportional scales offer. They point out the dance partners in the design so we can then make judgments about how each part is to be sized to make the composition flow.
Deconstructing a Design
Here’s a little exercise to help focus your attention toward proportions. Take a look at the drawing below and look closely to see what the proportional scales are revealing. Note which parts are linked together and what the proportional relationship is between them. You may find yourself reaching for your dividers rather than your trusty tape measure next time you work up a design.
This article originally appeared in the February 2019 issue of Popular Woodworking Magazine #244.