3 ms·

Yes, that's how the Moore Tool Company did it. However the first screw-cutting lathe actually dates back all the way to 1800. While as far as I can tell the fir

Yes, that's how the Moore Tool Company did it. However the first screw-cutting lathe actually dates back all the way to 1800. While as far as I can tell the first use of interferometry for distance measurement was the Michelson interferometer, in 1887; it took until 1960 for the meter to finally be defined in terms of wavelengths of light.

jbay808 6y ago
Oh, I see what you mean now; I misunderstood your question! Here's a screw cutting machine from Da Vinci's notebook: https://www.ssplprints.com/image/100676/leonardo-da-vinci-screw-cutting-machine-from-leonardo-da-vincis-notebook-1470-1520 https://www.ssplprints.com/image/100676/leonardo-da-vinci-sc... But as you observe, it already has a screw in it. Two screws actually, one on either side, which advance a carriage that cuts a new screw in the center from a blank. It can either duplicate the pitch, or using a gear ratio, it can cut a different pitch than the two master screws. The central screw averages the error of the two master screws, so with certain assumptions, the new can end up more accurate than either of the masters; the master screws can then be swapped out for new screws made this way, and so on. But there are limits to that approach, because common errors won't get averaged out. However you could, for example, assume that two screws made this way with the same masters are accurate duplicates of each other, then when you replace the masters with those two new screws, you can mount one of them flipped end-over-end, or with a rotational offset of eg. 90 or 180 degrees (offsetting the leadnut to compensate), and gradually average out more errors that way. Another way as you noted in a different comment is to use a long, soft leather lead-nut to average multiple threads, and use that as a master to create a new thread (assuming a low cutting force -- for example with force amplification, or for checking a thread, and so on). There are some first principles approaches you could use, like making a master cylinder and then wrapping a wire of constant-diameter around it to make a literal 'thread', and bonding it in place. It wouldn't be the most robust threadform but that's another way.

jbay808 6y ago

Oh, I see what you mean now; I misunderstood your question! Here's a screw cutting machine from Da Vinci's notebook: https://www.ssplprints.com/image/100676/leonardo-da-vinci-screw-cutting-machine-from-leonardo-da-vincis-notebook-1470-1520 https://www.ssplprints.com/image/100676/leonardo-da-vinci-sc... But as you observe, it already has a screw in it. Two screws actually, one on either side, which advance a carriage that cuts a new screw in the center from a blank. It can either duplicate the pitch, or using a gear ratio, it can cut a different pitch than the two master screws. The central screw averages the error of the two master screws, so with certain assumptions, the new can end up more accurate than either of the masters; the master screws can then be swapped out for new screws made this way, and so on. But there are limits to that approach, because common errors won't get averaged out. However you could, for example, assume that two screws made this way with the same masters are accurate duplicates of each other, then when you replace the masters with those two new screws, you can mount one of them flipped end-over-end, or with a rotational offset of eg. 90 or 180 degrees (offsetting the leadnut to compensate), and gradually average out more errors that way. Another way as you noted in a different comment is to use a long, soft leather lead-nut to average multiple threads, and use that as a master to create a new thread (assuming a low cutting force -- for example with force amplification, or for checking a thread, and so on). There are some first principles approaches you could use, like making a master cylinder and then wrapping a wire of constant-diameter around it to make a literal 'thread', and bonding it in place. It wouldn't be the most robust threadform but that's another way.