Bending Machine

2 x radius

There are two types of diameter. Inside, and outside.

In pipe, the inside diameter contains the hole. The outside diameter is where the pipe stops. To make pipe, you would need a third dimension, length. Anything under a certain length, depending on diameter, would be considered a washer and would not be suitable for use as a pipe.

Hope this helps.

Just in case, I'll include this graphic from Wiki:

If this pipe were buried, the dirt would go on the outside, where it says CIRCUMFERENCE.

Let's have some constructive fun while we are trying to figure out what the OP wants.

There is a sphere, diameter not known. A through-hole is drilled through it, a diameter being its axis, hole diameter not known. The only thing known is that the length of the hole is 6". Question: What is the volume of material which is left ? Some images to help.

If you know the answer, please wait for us mere mortals to work it out, please, thanks.

It can be done with calculus.
But calculus isn't necessary; there is a geometric solution.
There is also a trick that makes simple arithmetic enough.

This could be a good Newsletter Challenge.

There is also a trick called solid modeling.

Ah, yes, the desk jockey method.

However, the number 113.1 sort of loses its geometric meaning.

Bin out 'minding' my Small all night - sure I could crack it, will have a go in the morning. Please don't give it away too soon.

I trust "Cavalieri's Principle" will not be too big a giveaway. (Nor Archimedes' Method of Exhaustion.)

I once had a napkin ring 6.00 diameter but the idiots forgot the hole.

Do you mean what is the standard bend radius in sheet metal?

If so, r = 2T

(see 1 for further computations required)

Whatever happened to this thread? With those clever clues from Tornado and 34.5, i looked forward to a spate of Ah...so that's it! responses. Well, some pan out, some peter out i guess

Why not re-post in it's own right.

_{(This thread is probably a bit 'specialist' for the usual suspects)}