3 ms·
> In fact I don't know of any other good way of obtaining a straight edge from scratch quickly A string made taut between two points is surely a better way? An
by globular-toast 4mo ago
> In fact I don't know of any other good way of obtaining a straight edge from scratch quickly
A string made taut between two points is surely a better way? And works at much bigger sizes too (people build walls and foundations using this technique all the time). The paper is less useful in practice because any paper you find is probably straight and square anyway.
Still, I had fun thinking about this as I definitely hadn't considered it before.
- srean 4mo agoI have an asterisk in my post addressing that :) Happy to have picqued your mind. BTW, your method was the method of choice for the surveyors of the Nile, from the Egyptian civilization. Paper is hi-tech and was not available until much later, and as you mentioned doesn't scale. But if I have misplaced my ruler ...
- dotancohen 4mo agoOver long distances the string will sag in the middle. That's one of the reasons (not the only reason) construction uses lasers today.
- gacgacgac 4mo agoFolded paper won't?
- josefx 4mo agoFolded paper has some structure, so not as much?
- boothby 4mo agoIf anybody has ever tried folding a very large paper (or, bedsheets, tarps, etc), they'll realize the wisdom of this comment. Our intuition from folding paper on the order of several to tens of centimetres does not scale to arbitrary size and precision. Paper is relatively rigid, but its rigidity is finite and ensuring local-to-global flatness becomes a painstaking endeavour.
- srean 4mo agoThen there is the puzzle of coming up with folds to intentionally increase the rigidity of the surface. Essentially, using Theorema Pizzarium
- boothby 4mo agoIt depends what you need that line for -- if you're projecting onto a wall, that sag matters. If you're projecting onto the ground, it doesn't.
- rolph 4mo agoyeah its pretty hard to get new help to pull hard without fear of breaking the tool, coincidentally the beam width of a laser will increase over long distance, similar to line slack sagging over long distance.
- dotancohen 4mo agoThe DeWalt that I've been using recently had a bright green line pencil thin, in the sun, easily ten meters from the device. That's far enough to do an entire patio - ten meters in each direction. I don't know about longer needs, such as sidewalks, but for building construction the DeWalt was excellent. I've never tried other brands.
- rolph 4mo agothe really serious guys use GPS based equipment, and its serious stuff, being able to center up on a 1/64 inch brad tacked into the asphalt. [that 50,000$ ufo on a tripod by the highway, dont try to steal one, man do they ever know exactly where they are] yeah i like team yellow too :) the beam spread is what you want to check out if your serious about > 100 ft distance https://www.gpsalaska.com/ https://www.gpsalaska.com/ ^ this is a very commercial website, but example of higher end equipment and technique