English language

How to pronounce emery rock in English?

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- Hello, Nikolay.
- Hello.
- You know, Nikolay, Im full of grief.
It often happens that on various Internet forums and in social media
I have to communicate with people who actually argue
that ancient Egyptians had zero skills.
Though all of us read about them in schoolbooks and watched some films.
In other words, ancient Egyptians allegedly didnt have any tools and technologies
necessary to create all those things
that are shown to tourists in Egypt nowadays.
Even guides in the Museum of Egyptian Antiquities in Cairo
say that they dont know
how such impressive bores in granite could be made.
As far as I understand, you do know how such bores can be made.
And in your experiments you have proved
that this can be done with tools
which ancient Egyptians had at hand. Such as, a simple copper tube.
Am I right?
- Yes, sure.
- But how?
With a copper tube?
- With a copper tube.
- But copper is softer than granite.
- It is softer.
But it does not drill granite.
- And what does?
- Abrasive mineral.
- Like, ordinary sand?
- Yes, quartz sand which can be found at a riverbank or other places.
Beside sand, they also used corundite
or emery rock for this purpose.
They knew how to mine and use it. Corundite was even identified inside one of granite samples, that is, in a bore.
Also, today we know deposits where Egyptians could mine it.
- And is this tool made by you?
- Yes.
- Why is it shaped like that?
Lets look at its structure
I see this copper tube.
- Yes, the copper tube is the main component here.
And the handle is carved out of a sapling
which Ive chopped in the nearest grove.
I had no time to look for something better.
It is curved, but it works.
- And what is this?
- It is a balance weight.
So, if there is some obstacle in the stone or something jams
the balance weight helps to grind this obstacle
and it's efficient.
- What is it made of?
- This time Ive cast it of plaster.
But it is also can be made of stone.
The simplest balance weights which we can see
in Egyptian frescoes are made of several separate weights.
These may be either stones or sacks with sand, for instance.
Egyptians simply secured those weights with ropes.
It also works well
Ive tried this method and shared photos
So, in general, everything here is authentic.
- Just like in ancient times.
So yes, you said we can drill a bore
in a piece of granite using this stuff?
- For sure.
- Well then, lets start our experiment.
First, we have to secure the piece of granite, because it is pretty small.
Its not a granite slab which could be just laid down and drilled.
Thats why we have to hold it in place somehow to prevent its displacement
This cobblestone is rather small, and the first question people ask is
how can we drill a bore in an uneven surface? What do we have to start with?
But the method is as old as the hills.
This plank will help us to hold the drill bit, that is, the tube in place and prevent it from moving aside.
Now we are going to secure it and press down. After this we can drill without worrying about of slipping or displacing our tool.
Well, I think we can start now.
- So, we wont use a laser?
- A laser?
Im not sure Its hard to guess, where it can be mounted here.
Now I put some plasticine under the plank
to prevent abrasive from leaking out.
Clay would be a better choice in this case,
but I had no time to look for it.
Sometimes, we can see that Egyptians gouged out
a small pit in stone
and then drilled in that point.
And they didnt use plasticine or something
because the pit itself held
the drill a bit and the sand.
Here, lets make it like that
Lets press it
Remove excessive plasticine
and fix the plank with F-clamps.
- These are not ancient Egyptian F-clamps.
- Well, if we had a larger stone, I would have taken a longer plank,
laid it onto the stone, and called somebody
with ancient Egyptian feet to stand on it
to press and secure it.
The drill bit eats into the first millimeters faster,
so, fifteen minutes is enough to make a groove out
of which the drill bit wont jump. - And we wont need the plank.
- No, we wont. But still we will leave it in its place, just because
here we have a groove and abrasive is not leaking out of it.
So, this is just more convenient.
Also, Ill make a plasticine bead, a kind of a tray
where we will be filling in with abrasive.
- Everything is thought out.
- If we had a larger stone,
we would have piled sand into a cone shape without any bead around it
and poured water just right there.
But here we shall make a bead just like this
and then fill it with water just to make our task easier.
Of course, we can pour water from above.
But if we have a bucket lets use it.
- We might do that.
- Handymen.
- Smartly done.
- We need a laser.
- It would be easier with a laser. - Yes.
Well, lets pour sand right here. In fact, it is black carbolite
with various admixtures.
I think that natural corundite would work better.
Lets put it here
and pour some water.
- I hope the water is from the Nile?
- Surely. Its from my weekend house, from a cask.
There are even some gnatworms.
So, everything is done right.
- Indeed, the whole secret is in gnatworms.
- Right you are, they gnaw granite out.
- Gnaw out, yeah.
Now, lets proceed to the most interesting part.
- Show us your best stuff!
- Lets start.
- Lets position it into the place
Done. Speed up now.
- Alex, the water is leaking out too fast. Lets stop.
The water is leaking out.
- Why?
- I guess there is a leak in plasticine under the plank.
- Lets look at it. - See?, Im pouring water and its leaking out.
- Well, lets then open it and have a look.
- Lets see, what weve got.
About forty minutes of drilling.
They couldnt do that!
Now I want to say a few words about what we are doing all this for. For what purpose we are blistering our hands for two days
and sweating over some strange experiment.
The thing is that in the recent years quite a few people have become active in the internet
who pull the wool over others eyes
in blogs and in social media.
They argue that historians allegedly fool us,
that history is all faked-up, and that everything has not been
in the way history books tell us.
In particular, they argue that the ancients were
unskilled butterfingers, nearly talking apes'
who couldnt make anything themselves.
According to them, the truth is different, and all great monuments
in the Americas, in Egypt, in China, and so on were created by aliens,
Atlanteans, or some other mysterious civilizations.
Besides, people of this sort are rather aggressive.
They dont read, dont know,
and dont want to know anything.
With this background they naturally sell fiction, not facts to their audience.
They show some impressive pictures, tell some wondrous stories
But in my opinion all this leads to destruction
of the Russian education and science.
So, when we, and me between others,
first attempted to popularize science, we found out that
if something was written in popular articles or even mentioned in public lectures, it anyway failed to convince people.
That is, people need some action,
some material evidence to see with their own eyes.
So, we decided to shoot a series of videos
of practical experiments in order to show
these ancient technologies in process
and prove that ancient people were capable of pulling off
rather complicated technical tasks
using such simple, even primitive tools,
and there is enough
well known archaeological evidence.
I often get messages like this: You are armchair scholars.
In theory everything looks fine,
but lets see what you can make in practice.
Here you are! We can make this, and you see the results.
One of the frequently asked questions is
How it is possible to drill overlapping bores?
It seems impossible. If one bore is already drilled,
the other one supposedly will be displaced,
because the drill bit will creep away.
In practice, there is nothing difficult. The method is known since Adam was a boy
First, we put a template onto the point here a bore will be drilled.
We drill a bore,
then shift the template
and drill another bore.
And thats the secret.
In such a way we can drill
as many bores as we need.
Then we can beat out drill cores
and get a bigger cavity of some complex shape.
We have drilled through about 48 mm,
that is, we are slightly ahead of schedule
and are worn out.
- Close to that.
- So, ancient Egyptians needed rest.
So, Nikolay, lets finish
and see the result.
So, what do we have here?
Fifty millimeters.
Forty nine point eight, to be more specific.
Good, but there should be fifty millimeters exactly.
Now, the most critical moment:
we have to draw out the core without damaging it.
But its an easy task. - With a small chisel.
- Yes, we work with a chisel in this way.
- Wow!
Just two knocks.
- Just workmanship.
- Great!
We sat down to take a rest
and discuss the fruit of our righteous labor.
Well, the fruit looks like that. First, we can see here that
it slightly broadens to the bottom.
When discussing such granite cores from ancient Egypt, it is widely stated that
they broaden or, alternatively, narrow to the bottom and that it is impossible to get this shape
using the method which we have used a moment ago.
It is stated than some high-tech tool is needed for this purpose.
- And why it is shaped like that?
- Because the drill bit is wobbling during drilling.
And at the top it is wobbling heavier because at the bottom it is thrusting...
...against the material. - Wobbling means traveling like that?
- Yes, it is travelling and, thus, grinding more granite at the top.
Thats why the bore is V-shaped in the cross-section.
And this is our counter-argument
to the frequent statement that ancient Egyptians
could not make things like that.
In practice, there is nothing difficult.
In this sample it is clearly seen
that the bore matches its bore hole perfectly.
And it is clearly seen that the bore is broader at the top than at the bottom.
Well, I hope the question is resolved.
But I anticipate one more question
about sharpness of the cutting edge. Here is this cutting edge.
- Yes, it is argued that if one tries to drill granite
with a copper tube, it will go blunt very soon.
But here we see quite the opposite can you show this?
- Yes, the tube does not go blunt but becomes sharper.
- In other words, our drill bit is self-sharpening. - Yes, it is a self-sharpening drill bit.
Im not sure if it is visible here, but the wall thickness has decreased.
When we measured it before we started,
it was one point eight millimeters.
Lets measure it once more.
One point six.
- So, it turns out that the tube has become sharper.
- Yes, one point six millimeters.
That is, two-tenths of a millimeter have gone at this depth.
If we drilled deeper and
the balance weight were lighter,
the tube would become even sharper, almost as sharp as a knife blade.
You can google pictures
where a needle is stuck into the cut left after tubular drilling.
We also can stick a needle into our cut and get almost the same picture.
- A certain narrowing.
- Yes, the same narrowing is here.
It is a little bit thinner than in our samples, but
Here and the same is here. Just the same narrowing to the bottom.
- And here are those much spoken-about grooves.
It is argued that grooves on ancient cores
have a helical pitch of exactly two millimeters
and that it means that the tool
shall cut two millimeters with each revolution.
- Well, first lets see what do we have here
two millimeters or not Lets do it this way.
If the grooves are more visible now?
Put the ruler here
and measure the pitch.
- It varies.
At one point I see less than two millimeters, at other points it is only one millimeter.
Actually, the pitch varies pretty much.
- Naturally.
In the same way varies it around Egypt. In cross-section, bores can be either widening
or narrowing to the bottom.
At first, I experimented with a drill bit
with a longitudinal split.
That is, I took a copper sheet,
wrapped it around a metal tube and fixed with hose clamps.
There was a longitudinal split here.
The major advantage of this split was that it let the abrasive inside.
May be that was why the grooves
were more regular at that time.
In other words, if a drill bit has a split, then it will unbend itself during drilling because of
its own wobbling which is clearly seen in the video.
The tube unbends itself gradually,
and the bore becomes well-shaped in cross-section.
So, if we drill with a split tube,
then the bore will broaden to the bottom.
But if we drill with an unsplit tube like this one...
- Then vice-versa. - Yes, the bore will narrow to the bottom.
Because the tube will not unbend itself.
One can measure the bore from inside and see that it really narrows.
- Thats all, I guess. - Right.