Measure things without a ruler, story stick, etc.

[Alex Franke]

I was just out in the shop making some wall shelves for my son and I found myself taking rough measurements again by playing "air-piano" -- I've been doing that since before woodworking, and sometimes it's even easier than grabbing a tape measure. (In C, a major third is about 2 inches, a major fifth is about 4, and an octave is about 6.5.)

I also happen to know my arm length and wing span, which comes in handy sometimes, too.

Just curious if anyone else happen to do this kind of thing... I wonder if some people in the business can just accurately eyeball it -- sort of a "perfect pitch" for woodworkers. Can anyone do this?

(Oh, and dare I say, please keep it clean. )

[ironhat]

Yep, folks look at me like I'm crazy when doing the hand-spread measuring method. Mine is 7 7/8" which I round to 8". At the knuckles I'm 4" and these two alone have really saved me throughout my life - been using them since I was a kid. I also use the arms length holding a stick and hold my thumb where I measured a known length, say 5'. You then use the hand span method of end to end and add the lengths. That came from scouting in the '60's. I'd like to know more about the musical estimating.

You're an interesting cat, Alex!

[billwmeyer]

My dad always did this. His hand spread was 9". He was very accurate with that. He couls also pit in fruit or vegetables in a sack and be within 1 or 2 ounces of the weight every time.

Bill

[crokett]

I know a dollar bill is 6" long and I used to carry one in my wallet that was folded into 6ths. That has saved me more than once.

[cabinetman]

Just as in using a tape measure, once the finger and hand sizes are determined, it's wise to use the same hand throughout the entire project.
.

[atgcpaul]

Friend in college used to compete in the Science Olympiad in HS. One event
was to guestimate measurements without a ruler. He was accused of
cheating because he was always so spot on. Turns out, he measured the
lengths of the joints in his hand and used them for comparison. No ruler, no
cheating.

Paul

[leehljp]

Sam Maloof was asked by an apprentice once if he "had crosshairs" in his eyeballs. The apprentice was asking when Maloof started to drill a hole by hand at an angle in a chair. Measuring afterwards, it was perfect.

I used to be able to be able to "measure" a room by looking at it and guessing well within two inches on a consistent basis. And I knew a few others that could do that too. First - it is easy to guess within 6 inches, then by knowing standard measurements, room sizes, it could be narrowed to an inch or two. This is not something one thinks about, rather it is something that is just done.

While not "measurement" per se, when I want split an piece of plywood or board down the middle (without marking or a guide) to break it down - on a TS or BS - on most occasions, you would think that I measured it and used a guide.

Some people just have an "eye" for this sort of thing. It does have to be developed but it becomes evident who does.

[Alex Franke]

I'd like to know more about the musical estimating.

Most musical keyboards are sized so that an octave (e.g. the distance between one pitch and another with double or half the frequency) is just about 6.5 inches. The patterns of the white/black keys repeat every octave, so for any octave you play, you're spreading your thumb and (usually) little finger 6.5 inches apart.

Most keyboard players can position their fingers (on either hand) to form a chord they think of, regardless of whether or not there's a keyboard to play it on. And most can pretty accurately move their arm to the right or left an octave, too.

So to find the next stud over, "air-play" the first octave, move right or left to the second octave, then move an octave over again and play a fourth (e.g. C-F, ~3 inches). That's roughly 16 inches.

[moc]

he measured the lengths of the joints in his hand and used them for comparison.

I was taught in medical school to measure the distance across the MP joints of my dominant hand (the joints at the base of the fingers where they meet the hands) because this is a very consistent length over time. Mine is 8cm. Knowing that length helps estimate other lengths.

Not sure I've ever used it in medicine, but it's come in handy at other times.

No pun intended.

*moc

[Ed62]

I've used the dollar trick, like David. I also use the width of my hand quite often for a quick estimate.

Ed

[mpc]

I've used a plain old sheet of 8.5 x 11 inch paper many times... including at the auto show to measure the tailgate width of many SUVs... will a 48 inch wide sheet of plywood fit? I forgot a tape measure last time I went to the auto show...

mpc

[JSUPreston]

I've used the joint measurement before (learned it in Scouts). With my eyesight, it's hard to estimate because I have depth perception issues. I've learned to compensate when driving, but just guessing a length is difficult.

If I'm not too sure of the length of a longer distance, I fall back into marching band mode. I know that every 8 paces is 5 yards (called 8 to 5), so each step is exactly 22.5". I marched for 7 years in HS and college, and my 8 to 5 is still spot on. I verified it about 3 weeks ago using a known distance.

I can't use the hand spread method...I was a trumpet player and we use the same 3 fingers and buttons all the time. We never bothered to measure the distance between the valves.