[airair]

http://www.lynnblakegolf.com/forum/thread5903.html

Okay,everybody, here we go!

I'm going to put these first lessons out in a 'bite-sized' format so you can get started immediately. While you're fiddling around with Hinges 'n Things, I can be writing the next lesson in the series.

First, get your T-Hinge (only). Leave everything else wherever it is. [Doug, you can take your stuff off the kitchen table if you need to ease the pressure!]

Notice that the hinge has three parts. From left to right we have:

(1) The hinge mount;

(2) The hinge pin; and

(3) The hinge blade.

Now, holding the hinge at about chest level, grasp the mount of the hinge with the thumb and four fingers of your left hand and the blade in your thumb and forefinger of your right. Got it? See, I told you this wouldn't be hard!

Now lets learn how the hinge works. Hold the hinge with its pin mounted vertically (at a right angle) to a horizontal plane --let's use the floor or a table top as a guide! -- and using your right hand, rotate the blade about its hinge. Back and forth and back and forth. Take the blade to its limit in both directions. Physically position the pin vertically to a horizontal surface, e.g., a table top or desk, if that helps. The blade is making the same horizontal motion as that made by a swinging door,right?

Notice three things:

(1) The blade always moves in a perfect circle around its pin;

(2) The blade always rotates at right angles (perpendicular) to its pin; and therefore...

(3) The blade is always vertical to its Plane of Rotation.

Holding the mount stationary, move the blade in a straight line. Trick instruction! Can't happen, right? Bummer!

Now try to move the blade in any way other than at right angles to its pin. Can't do that either, can you?

Now try to position the blade any way other than vertical to its plane of rotation. Sorry!

So, we now know how a hinge works when its pin is mounted vertical (perpendicular) to a horizontal plane (in our example reference, the floor or a table top).

Now let's see how a hinge works when we mount its pinvertical (perpendicular) to a vertical plane (for example, a wall). Still holding the mount and the blade as described, position the pin vertical to avertical plane. Physically put the pin vertical to the vertical physical surface of a wall if that helps.

Anyway, you now holding the hinge in such a way that it spin is no longer vertical to the horizontal plane (the floor) but is now vertical (perpendicular) to a vertical plane (a wall).

Now rotate the blade about the pin. Back and forth and back and forth. It is the same vertical motion a child makes on a swingset, right?

Notice three things:

(1) The blade always moves in a perfect circle around its pin;

(2) The blade always rotates at right angles (perpendicular) to its pin; and therefore...

(3) The blade is always vertical to its plane of rotation.

Holding the mount stationary, move the blade in astraight line. Trick instruction! Can't happen, right? Bummer!

Now try to move the blade in any way other than at right angles to its pin. Can't do that either, can you?

Now try to position the blade any way other than vertical to its plane of rotation. Sorry!

Does any of this sound familiar!

So, we now know how a hinge works when its pin is mounted vertically to a vertical plane (in our example reference, a wall).

Now let's see how a hinge works when we mount its pin vertical (perpendicular) to an angled plane (for example, a pitched roof or aloading ramp, but it could be any plane between horizontal (the floor) and vertical (a wall). You see, there is only one horizontal plane, and there is only one vertical plane. But...there are an infinite number of angled planes! For purposes of our experiment, choose the angle you like the best!

Still holding the mount and the blade as described, position the pin vertically to the angled plane of your choice. [Let the jury note that Yoda is not a The Way angled hinge rotator.] Physically put the pin vertical to some physical angled plane if that helps. For example, I just propped my thin yellow book The Golfing Machine up against my thick red dictionary. Looks like a yellow loading ramp and makes a very nice angled plane indeed. And I just positioned the pin of my hinge vertical to the little yellow book and can see clearly that the pin is vertical to an angled plane.

So, you now holding the hinge in such a way that its pin is no longer vertical to the horizontal plane (the floor) nor is it vertical to a vertical plane (a wall). Instead, the pin is vertical to an angled plane .

Now let's see how a hinge works when we mount its pin vertical (perpendicular) to an angled plane (for example, a pitched roof or a yellow book propped on a dictionary). Still holding the mount and the blade as described, position the pin vertical to the angled plane. Physically put the pin vertical to an angled plane surface if that helps. You are now holding the hinge in such a way that its pin is no longer vertical to the horizontal plane(the floor) and no longer vertical to a vertical plane (a wall). The pin is now vertical to an angled plane.

Now rotate the blade about the pin. Back and forth andback and forth. It is the same angled motion a paddle wheel would make if it were tilted from its normal vertical position, right?

Notice three things:

(1) The blade always moves in a perfect circle around its pin;

(2) The blade always rotates at right angles (perpendicular) to its pin; and therefore...

(3) The blade is always vertical to its Plane of Rotation.

Holding the mount stationary, move the blade in a straight line. Trick instruction! Can't happen, right? Bummer!

Now try to move the blade in any way other than at right angles to its pin. Can't do that either, can you?

Now try to position the blade any way other than vertical to its Plane of Rotation. Sorry!

Does any of this sound familiar!

So, now we know how a hinge works when:

(1) Its pin is mounted vertical (perpendicular) to a horizontal plane (the floor or table top);

(2) Its pin is mounted vertical (perpendicular) to a vertical plane (a wall); and

(3) Its pin is mounted vertical (perpendicular) to an angled plane (a pitched roof or ramp).

In other words, we have learned that "the blade of a hinge is always vertical to its Plane of Rotation" (Glossary /Hinge), no matter which of the Three Planes of Motion that happens to be.

Whew, this has been hard work!