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Wringing

en.wikipedia.org

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Re: Wringing

#11

Post by Bizarro »

Great stuff. We need more of these types of science tidbits on HN. And good links by the commenters too.

I love Feynman's classic style of "explaining to a 5 year old" on Cold Welding.

The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to “know” that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms “know” when they are not on the same part.

— Richard Feynman, The Feynman Lectures, 12–2 Friction

Re: Wringing

#12

Post by greenyoda »

TeMPOraL wrote: post #8

I wonder how stable is such a "wring joint" over time and over mechanical stresses like temperature change and vibrations. Could you use this feature to e.g. attach stuff as a product assembly technique, as a temporary/non-destructively modifiable alternative to gluing or welding?

The joined blocks can be pulled apart with you hands. See the first video posted in this comment:

https://news.ycombinator.com/item?id=20366089

So the bond is not comparable in strength to gluing or welding.

Re: Wringing

#13

Post by stan_rogers »

TeMPOraL wrote: post #8

I wonder how stable is such a "wring joint" over time and over mechanical stresses like temperature change and vibrations. Could you use this feature to e.g. attach stuff as a product assembly technique, as a temporary/non-destructively modifiable alternative to gluing or welding?

See "cold welding". As far as actual gauge blocks go, they're relatively easy to separate by sliding after you're done with your measurement or set-up. (Good Jo blocks are horrendously expensive. You wouldn't want them to be single-use items.)

Re: Wringing

#14

Post by TeMPOraL »

greenyoda wrote: post #12
TeMPOraL wrote: post #8

I wonder how stable is such a "wring joint" over time and over mechanical stresses like temperature change and vibrations. Could you use this feature to e.g. attach stuff as a product assembly technique, as a temporary/non-destructively modifiable alternative to gluing or welding?

The joined blocks can be pulled apart with you hands. See the first video posted in this comment: https://news.ycombinator.com/item?id=20366089 So the bond is not comparable in strength to gluing or welding.

I watched both. I know it's not comparable, but it seems plenty strong. In the case of the video, I'd guess if you'd double the contact surface, you could easily hang a coat on it. My question is, how long would the join last.

Re: Wringing

#16

Post by war1025 »

ndespres wrote: post #9

If you're interested in how gauge blocks fit into the history of precision engineering, a new book called "The Perfectionists: How Precision Engineers Created the Modern World" puts them into context, and presents a very interesting perspective on the events and developments that brought us into modernity. These blocks feature strongly into the industrial revolution. I strongly recommend the book! https://books.googl…

I saw this book at the bookstore precisely one time. Made a note to look into it in the near future. And then was never able to find it again. Will have to look a bit harder maybe.

Re: Wringing

#17

Post by linsomniac »

lqet wrote: post #2

If you (like me) read the entire article without really getting an intuition for these "gauge blocks", here they are in action: https://www.youtube.com/watch?v=gbsd2OpPOMw https://www.youtube.com/watch?v=2lOOl3VxOtE

The first is an AvE video, the one that introduced me to Wringing.

There's also a Cody's Lab video where he sees if they will wring in a vacuum: https://www.youtube.com/watch?v=jNEvS_bjKIo (using AvE's blocks)

Re: Wringing

#18

Post by stan_rogers »

TeMPOraL wrote: post #14
greenyoda wrote: post #12

Earlier quoted context omitted.

The joined blocks can be pulled apart with you hands. See the first video posted in this comment: https://news.ycombinator.com/item?id=20366089 So the bond is not comparable in strength to gluing or welding.

I watched both. I know it's not comparable, but it seems plenty strong. In the case of the video, I'd guess if you'd double the contact surface, you could easily hang a coat on it. My question is, how long would the join last.

For about as long as the parts on both sides of the join stay flat. And therein lies the rub. Permanent cold welding works just fine on small contact areas, but on anything large you're at the mercy of thermal movement, etc. How much can that be? Quite a bit, actually [1]. That's just breathing on a braced precision straightedge, and the difference in temperature across the piece is easily measurable.

[1]https://youtu.be/UG6LV8v8W-0?t=1922

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