try square question

[George]

Yep, made us stroke through the zero when hand-copying.

Still say "decimal" instead of "dot" sometimes out of habit.

[J. Clarke]

Oh for zero and eye for 1 are probably the two most common errors in FORTRAN programming. I never will forget watching a PhD computer scientist struggling with one of her programs one time. After pounding into us "use meaningful variable names" she wrote "DO 100, I (the letter eye)=I (the letter I) TO 100" and then couldn't for the life of her figure out why it wasn't behaving as expected. (note--please don't bellyache about my syntax--it's been about 20 years since I wrote my last line of FORTRAN).

It doesn't help that I through (IIRC) N are implicit integers in FORTRAN so the lazy programmer's instinctive reaction is to use I for the the loop counter.

[patrick conroy]

"tri-square"

Or, something more insidious - I smell the Marketing Dept at work. Tri (Triple Functionality: Try, 45, ruled) Square

[J. Clarke]

Yep, but the Marketing Department often changes the language. See for example "Kleenex", "Velcro", and "Xerox", all of which have "generic" alternatives but all of which are often referred to in the generic by those brand names.

[George E. Cawthon]

I didn't quite understand that statement, but my interpretation is that you are saying Marketing Departments are responsible for using Trademark names in place of the general term, such as using Thermos to refer to any vacuum bottle or Fridgedare for any refrigerator. If that is correct, then your premimis is wrong. "Kleenex", "Velcro", "Xerox" and a great many other trade names were the first of their kind or the dominant brand. It is just people at large with their normal sloppy language that started using the brand name for any product of that kind. In fact, the marketing people fought against using their "trade name" as a general term. As an example Thermos was constantly advertising that not all vacuum bottles were not a Thermos and indicated or infered that a Thermos was the superior product.

I think applying Occams Sword, to the "tri-square" question would indicate that hasn't any subtle or insidious intrepretation. Rather, it is likely due to common misunderstanding, ignorance, and laziness.

[J. Clarke]

Regardless, the marketing department makes up the word that then becomes part of the vernacular. If nobody had made up the words "Xerox", "Kleenex", "Velcro", "Thermos", etc then they would not be part of the language.

By the way, you want to see people get confused, mention "Nissan Thermos"--people think you're talking about a premium that comes with a car.

[mttt]

I thought it was a razor. Which simply points out that it is a marketing gimmick. Give away the razor and sell the blades.

Nice attempt at a diversion. "Look! There's Elvis!"

You're a member of the Cabal aren't you?

[bridger]

TINC

[George E. Cawthon]

Damn. You're right it is razor. Must have been thinking of the Gordian knot.Giving away the razor and paying thru the nose for the blades (same with ink printers) IS a marketing gimmick. But what we were talking about isn't one. Cabal. Nope we don't need not stinking cabals.

[Anonymous]

It all depends on how much error you are willing to accept.

Woodworking does not require the same level of precision that machining does so the tools for each trade, while sometimes similar in purpose, are different in execution.

Bill

[Anonymous]

>

Yes, it is a try-square ... to 'try' the trueness of an edge or face.

But just to keep things lively, consider that the straight edge provides the third angle. 45, 90, 180 ... there's your three angles.

The machinist squares are not marked with distances because they are only used to test for squareness and even then, only on comparatively rough work.

Bill

[Anonymous]

The fixed squares (try-squares ... there are different types of squares [ box and cylinder come quickly to mind]) are intended to be calibrated / corrected by the user.

I'll leave it to the reader to figure out how this is done.

Bill

[George E. Cawthon]

>>

Yes 180 degrees is a certain amount around a circle, but a straight edge is an angle? Ok, how about this, "the shortest distance between two points is an angle?" Something just doesn't seem right about that.

[Elwood Dowd]

The truth is stranger than fiction. 180 degrees is just as arbitrary an angle as any other.

Heck, it's not even always true that the shortest distance between two points IS an angle. Try going in a straight line from New York to LA and you'll see what I mean.

[J. Clarke]

If you actually could do that it would be the shortest route, but that would have you 200 miles or so underground somewhere in the Midwest. Since we are compelled to move on the surface of a sphere we are compelled to take curved paths.

Regardless, an angle is not a distance. As for 180 degrees being an angle, yes, it is an angle, but measuring it is not usually something that one needs to do.

[George E. Cawthon]

Well if you take a straight edge 36 inches long, where is the axis of the 180 degree angle. Is it at 15 inches, 20 inches or some other distance from one end. Just how do you figure the length of each leg of the angle? If you think 180 degrees is an angle, then you better be prepared to point to the axis point, and if you don't point to the exact point that I have previously determined it to be then be prepared to forfeit your reward.

[Todd Fatheree]

Excellent straw man. Unfortunately, there are many mathematical concepts that are not easily defined. It doesn't, however, mean they aren't true. For example, take the concept that a circle of infinite radius can be represented by a line. Where is the center of a circle of infinite radius? I'd say a 180 degree angle has an infinite number of axes.

todd

[J. Clarke]

Why would you want to measure the subtended angle of a straightedge? Now, consider something like a door or a wing-sweep actuator, where you have movement possible thorugh a range of angles.

[Elwood Dowd]

Okay, okay... dig back into 2nd semester college trig....

18 inches. I made that arbitrary point up.

The axis point is arbitrary if you think of a 180 degree angle as a straight line (which it is for practical purposes). In the mathematical realm, however, the axis point is where the two sides of an angle meet. In this case it is wherever you put it along that line---a quality which is unique to 180-degree angles. Do I win a prize?

[Bill Rogers]

Reverse the argument. Take two arms, and swing one around, measurig the increasing angle. Do you stop measuring when they line up? Any measure prior to that is less than 180 degrees, and any measure past that is greater than 180 degrees. So, the measure of that *must* be

180 degrees.

It's like an argument about zero: What's 5 - 3 ........Ans: 2 What's 5 - 2 ........Ans: 3. What's 5 - 5 ........Ans: "I dunno."

If there is no agreement for 180 then there could be more argument about zero, with such nonsense as "You can't measure what doesn't exist." Besides, we are not going to solve the problems of mathematics in this conference. There's little enough here about woodworking, so let's stick to something we know, like the difference between a "tri square' and a "try square". :-)

Bill.