Wild_Bill wrote:
If I understand the method you're questioning, it would be described
as, putting the square tubing in the inside corner of a square.
That's not the proper position of the square, for doing the layout
work we've been discussing.

The method I had described is done by placing the square straightedge
(or rule) flat on the tubing side, and perpendicular to the length of
the tubing. The straightedge is laying flat on the side of the tubing.
The thicker part of the square is then touched/held on the adjacent
side of the tubing, with with the length of the thicker part
alongside the tubing. The straightedge will then represent a line
across the tubing that is square to the length.

Most formed square tubing has a significant radius at each corner,
but the face of the thicker part of the square can be extended if
needed. The contact face of the thicker part of the square could be
extended (sideways) with a parallel or similar flat piece of stock,
by attaching it with thin double-sided tape (not the foam type).
The wider surface would bridge the radiused area, and allow surface
contact with the adjacent side.

Generally, I just tilt the thicker part of the square slightly, to
make flat contact with the adjacent side of the tubing. This will
cause the straightedge to stand up slightly on the tubing, but the
inner/inside edge leaves close contact for scribing a square line.

There are squares that are both styles you illustrated, but the more
common type has the straightedge located in the center of the thicker
section (A).
When scribing the lines on square tubing with radiused corners, one
needs to "sight" the lines of adjacent sides, since the line scribed
on one flat side of the square tubing won't continue over to the next
side. Solid square stock (like some lumber) has sharp corners, so a
scribed
line is easier to extend around the four sides.

If a precisely squared section of angle iron were used for the square
tubing layout job, the two adjacent sides of the angle would show a
continuation from a scribed line on one side of the tubing to the
next side.

Hi Bill, and thanks again for your help. Now that I understand this method,
I will certainly acquire a proper square. I do agree that my current
project may likely be more suited towards using a well-squared section of
angle iron (due to the large corner radius), but the layout accuracy of my
other projects will benefit from the addition of a square to my arsenal.

On the topic of squares, I looked at the one I am considering getting:

http://tinyurl.com/2cyrbvc

but it looks to be of a type represented by model "B" in the following
figu

http://img228.imageshack.us/img228/9239/square02.jpg

If this is the case (I cannot get a good enough look at the square to tell
for sure, but many other squares seem to be of that type), I would not be
able to use it using the method you outlined.

Do you know of a similarly priced ($20) square or series of squares which
would be constructed similar to model "A"?

Thanks again for your help with this,

Jon