Extremely clear---one of those things that seems obvious once it is pointed it out.
If I understand you, even though you apply only compressive forces, the failing tool is always under shear stress, tensile stress, or both, because the pressure deforms it (in various ways, depending upon...
Oh! I see. I seem to be picturing this in oversimplified terms. Yes, I do know what the definitions of tension, compression and shear are, but I can see that I wasn't picturing how one could give rise to the other.
So even though it looks like the hammer is only applying pressure in one...
Ok, I think your picture illustrates a misunderstanding. Sorry, can't send you a picture at the moment, but perhaps your picture makes it unnecessary.
The picture is typical of a machine cutting tool, in that the back side of the tool is NOT under pressure from the material being cut, but the...
As requested, here are three pix. One compares a marble punch to a granite punch. You can see that the granite punch cannot penetrate. (It is carbide tipped---even the hardest steel is rapidly destroyed by granite.) The other is a picture of a bush hammer---each point is quite similar to the...
Yes, you are right that normally the later stages of carving usually obliterate the evidence of the earlier, but
Not all sculpture is completed all the way around, because the back is not meant to be seen.
Lots of pieces get abandoned part way.
Bruised stone leaves permanent evidence in the...
Oh yes--your last point. Yes, ancient peoples did use stone as we would use a bush hammer. The Egyptians for instance used diorite balls to reduce granite. But this was not really the practice in the Agean region because marble and limestone aren't that hard. They tended to use chisels to cut...
Good question #1: The historical usage of the tools is pretty well known: (a) There are a number of partially completed pieces from the Sixth through the Second C. BCE, that make it very clear. The marks of the tools are very easy to read---they look nothing alike, and they are exactly like...
So THAT'S what tensors are! You wouldn't believe the stuff they forget to teach in art school...
Actually, what happens in the ROCK isn't so much the issue, as what happens to the TOOL. When I look at the rock, it seems pretty clear that what you guys describe is exactly what is happening...
The use of the rock drill is interesting. We're talking about the Fourth to Sixth C. BCE with these tools. They seem to have mostly used drills that twist---in the early days, spun between the palms, but usually spun by a bow pulled back and forth. You can tell by the marks.
But they...
Thanks for these very illuminating replies---extremely clear with respect to how the tool acts on the marble. This is indeed the first part of what I need to know. The second part is actually the critical thing: how the marble acts on the tool.
For context, the use of the punch came in early...
It is not often that artists need to deal with physics questions, but here's a good one (more than one actually). I hope someone out there will be in the mood for addressing this. It has to do with stone-carving techniques.
If anyone wants to know more context, I'll be glad to fill it in, but...