I’m one of the lucky (yea that’s it) few, that has sweat/skin oils that rust metal. I’ve read some place that roughly 10% of people have this problem. Most of the time it’s not much of a problem, but if your involved in woodworking or metalworking, it’s a real problem because a lot of tools are made from metals that rust. Rust causes the tool surface to become uneven, and while it’s mildly annoying on most tools, it’s a real problem on a precision tool like a square.
Most squares are made from tool steel, and most tool steels aren’t know for their rust resistance. Fortunately, Peachtree Woodworking sells special layout squares made from stainless steel. I’ve had them for about month now, and they are well worth the price in my opinion. They’re exceptionally square, and their unique design means you don’t need 3 hands to use them.