amdx actually said:

Ya, I am to. But first let me say this, The first spec you posted,
0* 14' plus or minus 10', seems this isn't as critical as some posters
are making it.

Now that I've done some more research, I have a better handle on 'toe' so
I'm going to agree with you that getting toe precise to 2 minutes isn't all
that important, in all likelihood.

For *setting* toe, especially in the rear, it could easily be that 0 toe
(degrees or inches) would be just fine, or, maybe, to take up some
suspension slop, a "smidgeon" of toe (maybe 1/16th of an inch or less in
linear dimension no matter what the wheel/tire diameter).

This is to take up the slop in the suspension (perhaps slightly more in the
front if it's a typical RWD like all my vehicles are).

For toe, it is still a trig problem, but the problem is defining,
side b (a reference point).

http://www.carbidedepot.com/formulas-trigright.asp

I'm still confused how to convert toe from degrees to inches, but luckily,
there are web sites that will do it for us.
https://robrobinette.com/ConvertToeInchesToDegrees.htm

I wonder do the shops attach a laser and measure on a wall scale a
defined distance away?

Interesting you mention that, because the reason for the *far away* wall is
simply that the angle is small, right?

I don't know this, is it a single adjustment that moves both wheels or
do you adjust both wheels separately? (makes a reference even more
important)
Sorry just thinking on the keypad.

If you are talking about toe, I'm no expert, but the way I understand it is
that you lock the steering wheel in the center position first (which has
nothing, per se, to do with alignment but with esthetics) - and then - you
pick a side, and twist a tie-rod ever so slightly - which - depending on
the direction of twist, moves the front of the wheel in toward the
centerline of the vehicle - or outward.

So it's one wheel at a time, measured to the centerline.

Of course, you can assume all sorts of symmetries and do both wheels at the
same time, but conceptually I think of toe as a wheel-to-centerline thing,
to be done one at a time.

You have a trig problem and a measurement problem.
The measurement problem is more difficult.

That's an interesting observation that the measurement problem is more
difficult, but I think only if we try to measure degrees of toe.

If we measure inches of toe, the measurement problem is conceptually
trivially simple.

It is not be hard to convert the 14 minutes to inches using the wheel
diameter as one line.

I'm trying to find the triangle in the equation of toe in order to figure
out how to convert the distance measurement to an angle.

Here I just drew what is my first pass guess at where that triangle lies:
http://i.cubeupload.com/ZmdfeN.gif

Is *this* the trigonometric angle everyone is talking about?

The angle is how much more is the front of the wheel turned
in more than the rear of the wheel. I'll call the wheel 16"
from front to rear. (just realized this almost the same trig problem for
camber, just rotated 90*)

You make a good point here in that we really have a 3-dimensional X, Y, and
Z axis, each of which is rotated by 90 degrees (caster, camber, and toe).

I'm using the trig calculator above, this time the orientation is correct.
Put the following numbers in, (side c) = 16, (angle A) = .233. The angle
is .233 because 14min/60min = .233.
Your answer is (side a) which is 0.065". So, you want the rear of a 16"
wheel stick out 0.065" more than the front.
Not real easy to measure, But, if you could extend the 16" to 12 ft
(192") with a laser pointer, then (side a) is 0.781".
The laser must be perfectly square with the wheel.
Just some thinking. Hope it makes some sense.
Mikek

Just to ask to get me more firmly grounded, is *this* the triangle everyone
is talking about?
http://i.cubeupload.com/ZmdfeN.gif