a thousend of an inch... predynastic.

originally posted by: sapien82
is it physically possible to be that precise using stone tools and by hand ?

or is it only possible with machine precision work on a lathe

It's physically possible to do it by hand. Easier with a good clamp of some sort on a very flat base (easy to get such a base by rubbing stones - as the video also indicates. That's basically how we get flatness standards today - by rubbing two pieces of metal together.)
As the video says, most of these vases aren't nearly as precise as the one under discussion. While the precision is impressive, it's not remarkable that a few vases could have been made to such a level of precision, given what we know about the methods used.
For example, the perpendicularity of the mouth with respect to the top of the vase is controlled by the original hole sawn in the vase with a tube saw. Everything else about that subject feeds off the precision of the one cut. Get it right, and you're done with the perpendicularity issue.
The outside was pounded and pecked and then abraded with sand and stone before the hole was cut. The top would have been made flat before the hole was cut as well.

Harte

"Lathe" may be the term that's causing frustration here. It's a broad term. It's anything that can hold an object securely while you spin it.

Did the Egyptians know how to hold an object securely while they spun it? Or were they so dense that they couldn't figure out how to hold an object securely while they spun it?

If you think they were that dense, then I guess you think they didn't and couldn't have had, lathes. On the other hand, what if a few of them weren't that dense, and kept their methods a trade secret?

originally posted by: Harte

originally posted by: EartOccupantJust admit, that you don't know.

Now you want us to lie.
We know how this was done. It's displayed in ancient artwork at a couple of sites in Egypt. Tool sets shown being used in the artworks have been found as well. Also, it's been replicated in modern times by people that don't have generational experience in stone working.
Here's a book about it, not that you'll read it.

anarkia333data.center...

Harte

You're assuming that those paintings/drawings aren't esoteric nonsense. That's quite an assumption when it comes to ancient religious or political writings.

None of them depict a method of measurement, and "eyeballing" it wouldn't get you that kind of precision.


I highly doubt that the methodology used by a master craftsperson to create precise vases that were highly valued by Egyptian nobility would be public knowledge. Not a trade secret. No. Of course not.

And if it's a trade secret, then how does it end up in a depiction on a wall somewhere?

Nobility only values things that are scarce. Stuff the general public can't get, but they can get because they're "special".

They would pay high prices for something made by a secret machining method that only a select few craftspeople know how to replicate. But they wouldn't pay hardly anything if everyone knew how to make it.

a reply to: bloodymarvelous

"You said if it is a trade secret how did it end up as a depiction on the wall" The Lathe wasn't the trade secret, it was the skill of the person operating it. Our whole society works simply because of precision. If you cant make an interference fit for a bearing you wont have much at all.If you want stuff thats a thou perfect, you can do it on a lathe a good man can get down to tenths of a thou. But for mass production the stuff gets turned down on a lathe then it goes and gets hardened where the surface ten thou is really strong and brittle. Then it goes ironicaly to a grinding machine where another five thou is taken off and then the dimension is in the tenth of a thou range, this is done with a grinding wheel commonly made of carborundum dust glued together in some matrix which cements all the carborundum together. So we are still using stone age technology if you look at that way. Even then the grinding wheel has to be dressed so it is perfectly circular or it will just tear the peice to bits, and again ironicly this is done with a diamond tipped tool, which is dragged across the wheel as the operator sees fit.
The industrial diamond is set in a tool holder. But wait their is more, !! the surface of the peice being ground has to be so smooth that it will not produce friction or wear the tool cut out, because then the dimensions would change for the intended purpose. So the drawing will say it has to have a micro inch finish, so the slower the diamond goes acros the grinding wheek the smoother it is Then after you have done the job their is a scratch pad which you draw your fingernail across this pad has many micro inch finishes on it when you feel the surface of the peice coresponds to one on the scratch pad , thats the finish you have.So we are really still in the stone age.
My personal thinking is that they would have used the tool that we use to dress the grinding stone,industrial diamonds are cheap.But they might even have done the same thing as the above, because the grinder will do everything a lathe will do and more, if you want to go through steel like butter you drag the diamond across the wheel fast so it has more cutting action.I felt it worth mentioning as all grinders have a dog system to turn the peice, between centers.As it turns slow , its the wheel that goes fast. Sorry I think I am relying to Harte

originally posted by: bloodymarvelous
"Lathe" may be the term that's causing frustration here. It's a broad term. It's anything that can hold an object securely while you spin it.

Did the Egyptians know how to hold an object securely while they spun it? Or were they so dense that they couldn't figure out how to hold an object securely while they spun it?

They spun the tool, not the work.

They painted pictures of this, you know, so it's reasonably certain that they did it.

Harte

It's clear there were two versions of this. The real deal, and then the cheap imitations that started trickling in later.

How do we know those pictures are of the really precise vases, and not the cheap imitations that came later?