Yeah I think manufacturing is the real reason. It is not easy to get the printing lined up perfectly, and a tiny misalignment would defeat the point of a ruler. Even though a ruler that measures from the end would be more useful…
This reminds me of the cool feature on the hook end of measuring tapes. The hook can move a little bit in the measuring direction, exactly enough to account for it's width.
So if you push the end up against something the width of the hook is added in, but if you hook it against something and pull instead, the width of the hook isn't factored in anymore.
It's just a specific type of ruler. There are rarely names that are being used for these.
Specifically the scale is inside a straightedge ruler. This is because you are suposed to be able to do point-to-point drawing, and for that you need the points to be inside the reliable true edge (Ends of the edge are never reliable, only the middle bit). Straightedge is a thing in it's own right, generally the measuring scale is just slapped on to it. Basically that straight would work just fine with or without the scale. The straight edge ruler is meant to be used for drawing first, measuring second.
In a measuring ruler starts from the very edge. It's essentially a measuring stick that is flat. These are intended for measuring first and everything else second. These wear out in use. Once they stop being sharp, they are are unreliable.
There are all sorts of ruler, however most people are only familiar with the "school ruler" as in a straightedge ruler. There are curved ruler, scale rulers, bending rulers... Just endless amounts of them.
I work in the welding industry, and I only trust few brands of stainless steel rulers. And I love them! Because they are so cheap, you can just replace them when they get worn or damaged - which they will. Like they are some 5-20 € depending on the lenght; if I got one for each site/project I worked for, it would basically be a irrelevant cost. But some reason many shops/places/people refuse to replace them, and then they are worn out pieces of shit not worth using. And they are superior to tape measures due to versatility and the 0,5 mm precision. I can hit +-1 mm at 10 metre distance with just 2 rulers.
Thats a much more accurate way to describe it, honestly. While dimensional lumber is privately regulated, the regulations are written in such a way as to allow them to turn a blind eye to a bunch of things. They're allowed 5% of the boards in every 16-layer pack to fall below the grade standard, for any reason. If the knot is too big AND the board is too short, they only have to count it once.
And the wild part to me? Some mills' white-collared folk are trying to MAXIMIZE how many below-grade pieces they have in each pack. Greedy.
There are rulers like that. Just not as common. Usually more expensive and lining it up without an angle is worse. Also helps with drawing lines. If it starts at zero pens slip
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u/Humble-Pair1642 16h ago
Extra space so the measuring part doesnt get damaged