Why would I pay $300 for a framing square

[Jeff Maberry]

or out in the hot sun all day and you will know why aluminum framing squares are better then steel, they don't burn your hands like the steel ones do

[Trevor Goodwin]

Not long ago I had to get a straightedge. I was torn between aluminium and steel so I got one in both, a 500mm steel and a 1000mm aly. I don't think durability is a problem for the aly straight edge, it is a precision tool and you treat it with care. Do you buy a HSS chisel over carbon steel because it can survive a drop on a concrete floor?
The other argument I see against aly is that you can't run a knife along the edge, this is false. If the edge of your knife was really in contact with your steel straight edge then it would dull very quickly. My aly straight edge is anodized so it has a hard external layer that protects it from scratches. In hand, the steel straight edge feels more accurate, probably because it is much heavier, I'd say it's more suitable for machinists who need the highest precision. It also wants to rust whenever you touch it so I have to keep it oiled and away from wood dust.

[Patrick Chase]

Not long ago I had to get a straightedge. I was torn between aluminium and steel so I got one in both, a 500mm steel and a 1000mm aly. I don't think durability is a problem for the aly straight edge, it is a precision tool and you treat it with care. Do you buy a HSS chisel over carbon steel because it can survive a drop on a concrete floor?
The other argument I see against aly is that you can't run a knife along the edge, this is false. If the edge of your knife was really in contact with your steel straight edge then it would dull very quickly. My aly straight edge is anodized so it has a hard external layer that protects it from scratches. In hand, the steel straight edge feels more accurate, probably because it is much heavier, I'd say it's more suitable for machinists who need the highest precision. It also wants to rust whenever you touch it so I have to keep it oiled and away from wood dust.

The Al straigtedges aren't spec'ed as tightly as good steel ones. For example my 50" Al straightedge is spec'ed to +/-0.003" flatness over its length. My 48" Steel Starrett is spec'ed to +/-0.0002" per foot, or +/-0.0008" over the length. The Al one is also much less stiff, such that you have to think about orientation and support before relying on its straightness.

Of course both the Al straightedge and the Starrett are ridiculous overkill for woodworking.

[george wilson]

Good point about hot squares,Jeff. I did help build 2 houses in Alaska,and a garage in Va. after we moved here in 1957. But,it has been many years since I have built any houses. So,this is a good tip to know!

[Roger Nair]

I preferred steel squares and did not find that hot squares a problem, mostly because I learned what to do with a square when not in use. Place it so it can not be trampled and not perpendicular to the sun and convenient to being picked up. It becomes second nature, an automatic condition, it's just adaptation to daily rigors.

Squares wear from striking lines, all squares. It takes a while for wear to become noticeable. A square in a production setting will have hundreds of swipes daily, the absolutely miniscule mounts up. At some point, the wear becomes apparent and the tool needs replacement or one could adapt and mark and measure on the inside edges. Anyhow, a $300 framing square would not last longer or hold precision any better any of the other options. I would choose the $76 Shinwa, it has all the traditional scales 1/16, 1/12 and 1/10.

[lowell holmes]

I was a process plant piping designer for many years.
We carried framing squares when going into a facility to check or design piping drawings.
You're not likely to need this, but if you hold a square on a pipe to check it's diameter, a line will touch the o.d. of the pipe.
That defines the center of the pipe. and while your at it, you can read the radius of the pipe.
An old pipe fitter taught me that. I was too dumb to figure it out myself.

[george wilson]

I have an old book over 1/2" thick,with all the kinds of things you can do or calculate with a framing square. It has a huge number of uses.

[bridger berdel]

I have found my ordinary quality framing square quite accurate when I compare it to my $2500.00 24" Starrett machinist's square,even though it is one of those chomped out rather than the good,old quality ones with ground edges. It is only a framing square,after all. Not really intended for accurate cabinet making.

I have a few framing squares. the best of them is a heavy tapered stanley r100. the edges are milled. it was originally nickle plated, much of which still exists. it is covered in tables of things that don't mean much to me. it has always come out on top in any test of accuracy I have thrown at it- but I don't have a 24" starrett to offer it up to.

I would rather have a steel one than an aluminum one. Pretty anodizing or not! And,plastic stuff is right out of consideration. As said,they can be adjusted with a punch if not perfectly true.

I'm with you on the lack of enthusiasm for aluminum precision tooling. I mean, come on.

I do have an aluminum framing square that I keep as a jobsite tool and a general knockabout square for checking carcases during assembly and the like. it's lightweight, won't rust, and if it disappears on a jobsite somewhere I won't have trouble replacing it. I bought it new as a beginning carpenter. it took quite a few punch marks to get it to be anything like accurate, and I don't rely on it
for anything important.

interestingly, I have a stanley ar100. it has the same tables, the same taper and the same milled edges as the r100, but it is made of aluminum. it also tests out as accurate, but I don't use it much.

[Roger Nair]

Speaking of rafter tables, bd/ft table, octagon scales, et. al., I have found that a sci. calculator with trig and root functions far faster and easier than referring to tables. However the tables and the other little used vestigial scales 1/100, 1/12, 1/10 are handy for working out building problems on site and on the fly also as an education resource on the hows and whys presented to helpers on topics of older construction.