The Scale of Things

[ToyMaker]

Lots of us work with dimensions and numbers every day (sometimes all day ). So much so that we gain, over time, an intuitive feel for how big, how strong, how fast, things are. But for the rest of us, many (if not most) quantities are just numbers.
So, what is a pound-foot, and how much force in everyday lay terms does it represent?
What you will need: a 12-inch ruler and a pint (16 oz) of your beverage of choice.
What you will do: hold the ruler at one end keeping it even with the floor. Place the pint container on the free end. The force you feel is one pound- foot (you are gripping the ruler by just the very last quarter inch at the end aren’t you?).
So what? Well those industrial quality high priced 200 oz-in servos (or steppers), that you sniped off ebay for next-to-nothing, produce just about that much force (1 pound-foot = 196 oz-in).

For our metric friends what you will need is a meter stick and a small apple. Same exercise as above: hold the stick by one end; apply the apple at the free end. That’s about 1 N-m, or as it turns out, near 0.069 (about 1/15th) lb-ft.

If you have other real-world v. numbers-world examples I'd like to hear them.

robotic regards,

Tom
= = = = =
"Being stupid is simple, but being simple is not stupid."
- - Siva Perraju Tolety

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[ger21]

(1 pound-foot = 196 oz-in).

Isn't that 192 oz-in?

[wjbzone]

How about the term "Arm-Beer". Or would that be "Beer-Arm"?
Bill

[ger21]

An Arm-Beer is closer to a ft-lb (lb-ft?) than an oz-in.

[High Seas]

ToyMaker!
I just came across some files I'd misplaced and your thread started up again. Timing is everything.
I mentioned in a thread some while back about having 5 inches in your pocket - well it was taken the wrong way, so I let it go.
But the inch as you might recall is closely approximated by the length of the outer segment of you index finger. Now, we can count grains of corn or whatever - but the finger tip is close enough for a quick measure.

I'd been looking for other usefull measures for CNC discussions, and here are a few.
(Note I've made some approximations and rounding for comparison, so don't take a "gospel".)

Sign Painters will recall Gold Leaf - well, it is about 0.000003 inches (0.0001mm)
Aluminium foil (the thinnest) is about 0.00045 inches (0.01mm)
Thinnest shim stock (common) 0.001 inches (0.0254mm)
Human Hair 0.0028 inches (not the red ones) (0.070mm)
20pound paper 0.004 in (0.10mm)
100pound paper 0.007 in (0.18mm)

Those maybe useful especially when trying to explain how close you can cut to a customer or spouse.
I'd kind like to know how close people think they have to get to:
1. Make a "SnapFit" work. or
2. How close to cut inlay?
Jim
BTW for antique boat builders -- remember the cubit is about 18 inches (elbow to fingertip)

[jphagen]

Well, I have found it interesting to tell about the steam or air pressure effect.
On a square foot (12X12) at 15 psi it is just over a short ton (2000 psi).
If it is water no problem LEAK!! But if it is Air or Steam Run..

[ToyMaker]

ger21 wrote >Isn't that 192 oz-in?<

yes, you're correct. my guesstimator works better than my arithmeticker

robotic regards,

Tom
= = = = =
"It's better to introduce yourself to someone with whom you'd like to wake up than to wake up with someone to whom you have to introduce yourself."
- - Jim Blockinger