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Comment by dotancohen

17 hours ago

Over long distances the string will sag in the middle. That's one of the reasons (not the only reason) construction uses lasers today.

8 comments

dotancohen

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rolph  9 hours ago

yeah 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  8 hours ago

    The 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  7 hours ago

      the 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/

      ^ this is a very commercial website, but example of higher end equipment and technique

boothby  13 hours ago

It 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.

gacgacgac  15 hours ago

Folded paper won't?

  • boothby  13 hours ago

    If 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  13 hours ago

      Then there is the puzzle of coming up with folds to intentionally increase the rigidity of the surface. Essentially, using Theorema Pizzarium