Eyeball it
When measuring is overkill
Every rule is meant to be broken. Especially when it comes to rulers. I hope you enjoy this little break from the exacting nature of making. ~JRC
Measure twice; cut once. Truer words have never been spoken. Or have they? Is there a time and place to just eyeball it?
Of course, there is.
But it's not an excuse to get sloppy with your work. Instead, it's about economizing effort. And trusting your gut when the situation allows.
A small confession - I do like to measure, but not as much as I enjoy cutting. Or drilling. Or basically, everything else that goes along with making. But I appreciate getting things very close. So I measure obsessively. And as my maker skills have improved over the years, I find myself in a never-ending pursuit of exact.
Machinists often refer to this as "chasing zeros." It's where the maker shoots for thousandths of an inch accuracy, depending on the process and tools used. More and more, I am doing this very thing. Measuring, drilling, and cutting - I aim for close tolerances. If for no other reason than personal satisfaction.
On my table saw, for example, I am within a couple of hundredths of an inch on most cuts (and often much closer). This is fine for wood at the scale I usually work. When making smaller pieces or using metal and plastic, I aim for thousandths of an inch. Regardless, to achieve all this exactitude, one must measure. And measure again. And it takes a lot of time to get things this "right."
But a quality build need not be so exact. And sometimes, the time spent measuring could be better used elsewhere. Herein lies the genius of eyeballing it.
"Eyeballing" is what it sounds like—taking a look at something and making your best guess on where to make the mark. It's helpful in many applications when time is of the essence. It's also beneficial in less-precise builds where "close enough" will do fine.
Firewood is an extreme example. The standard length for a piece is 16 inches. But if you've ever bucked some timber for the coming winter, you know that rarely if ever, does one measure. Somewhere in the vicinity of 16 is all it needs. The goal is to get uniform lengths that stack well and fit in the stove, so eyeballing is more than appropriate.
But eyeballing works in a wide variety of applications, not only loosy-goosy cuts. Building a quick set of storage bins, one can eyeball measurements, no problem. Same with some jigs and other tool aids for the shop. And occasionally, choosing a spot for a single handle is best done by eye. And yet another - when parts are additive. This is when one piece butts up against another, and you need the whole length. It might be better to use the pieces to mark the next cut instead of using a tape measure.
Eyeballing, then, doesn't mean sloppy; instead, it can be the best way to do something.
Marking by eye can be darn close too. As a bit of a test, I grabbed a length of scrap from my wood bin and guesstimated the middle. The piece was 10 1/2 inches long, and I marked 5 3/16" by eye - a sixteenth off from the exact center of 5 1/4 inches. Not bad. And I suspect many of you could do the same.
Then there is what I like to call the "halfway-by-eye" measurement. It's when we take a known length to help us measure something. A foot is roughly the size of a shoe, so to measure distance, one can walk off the length. I watched my dad do this often as he planned large projects. It's when you count toe-to-heal steps.
Another halfway-by-eye method is the mental image we have of standard measurements. Many of us can "see" these standard sizes in our heads. Long ago, we learned a foot is "yeah-long" (imagine me holding up my hands illustrating this standard length); we've seen it so many times that we now have a good idea how long this common measure is (it's an ordinary grade school ruler, after all). Same for other typical lengths and, I suspect, volumes. Good cooks can eyeball a measure of salt. Or is that a matter of taste?
Anyway, using these "mental units," we do a good job measuring stuff without ever breaking out the tape.
The point here is that while exacting measurements have a time and place, they aren't always needed. Instead, a good eyeballing might be what a project orders. And instead of fumbling with units and measuring twice or more, measuring by eye allows us to move on to the most gratifying part of the process, which is pretty much everything else.
Until next time.
JRC
Great essay. Eyeballing does work in many situations as described. Here is another tip for those that find themselves in need to measure something but are caught without a measuring tape: use your body parts. I learned this while living in rural Costa Rica. In the countryside, practically no one carries a measuring tape with them but often someone needs to measure things (lengths of rope or wire, distance from a post to the next, etc.).
They use a series of "non-standard" measurements that they have arrived at by calculating and memorizing things like steps (1 long step = 1 meter or 3 feet); a "cuarta" which is about 20 cm from the tip of the thumb to the tip of the pinky finger on a wide-open hand; a "brazada" with is a length of rope or fishing line equivalent to 1 meter, calculated by holding the end of the rope or line in one hand and bringing the other end to a point in front of the chest. And so on.
The trick is to measure accurately ONCE the reference you want to create to eyeball it in the field. My examples that I use frequently:
- One inch = length of the second segment of my right index finger
- One meter = three feet = One long step (but not too long)
- 20 centimeters = Distance from thumb tip to pinky tip
Enjoy measuring yourself and becoming a living ruler!