Wild_Bill wrote:
Different layout jobs require at least a couple of different types of
squares. The combination types, with a sliding rule and 90/45 degree
surfaces are very handy to have. Scribing a measured line parallel to
an edge is one good use.
An accessory for a good combination square is the V that is useful for
marking the center of round objects.
The trouble with many import/generic low-priced combination squares
is that the components are cheaply made, so they aren't likely to
last long.
A good quality combination square will practically last indefinitely,
if it gets the proper care.

The fixed-type squares you've been referencing are useful too,
regardless of whether the straightedge extends outward from the top
of the thicker section (B).
The fixed type squares will stay accurate, unlike the cheap
combination-type squares with low grade components.
The accuracy of the fixed types can be compared with precision 1-2-3
blocks (or larger) and a couple of precision parallels. Some careful
filing can improve or restore the squareness.

Both types A or B would be suitable for your present task. Nearly all
of the popular tool dealers have cheap import grade, and also better
quality squares.

On rough, unfinished stock, there can be a lot of surface
irregularities that may have a major affect on accuracy when checking
square, or doing layout. Longer contact surfaces of squares can
average out slight waves in the surface, as long as there aren't any
"bimps" higher than the surface. Using a square that has a contact
surface that's too small can lead to a lot of errors and frustration.

THanks Bill, I appreciate your time.

Jon