I hit the STOP button.
"Hey, Tom, how was that sword made?"
"It happens that I am well informed on that subject, seeing as how I invented the process and made that particular sword myself," he said smugly. "First you get a good quality Damascus steel blade, which, by the way, were mostly made in India. Damascus was nothing more than a distribution point. You split the blade in half the hard way, right down the middle, through the edge."
"How do you do that?"
"Simple. You line up a nonlinear temporal field just right, then send one half of the blade a few minutes farther forward in time than the other. This gives you perfectly smooth surfaces, and since you're working in a vacuum, those surfaces are pretty reactive, chemically. Then you put a thin slice of diamond between them, about a hundred angstroms thick. You get that by slicing it off a larger block, using the same temporal cutting technique as you used on the blade. Then you clamp this sandwich together at four thousand PSI for two hundred years in a hard vacuum at room temperature. This welds the pieces together without harming the crystalline structure of the steel. You end up with as perfect a sword as is possible, with a pure diamond edge."
"Uh-huh. Where did you get a block of diamond that big?"
"Simple. You just put a block of graphite somewhere at thirty million PSI and two thousand degrees for twenty thousand years. It's not as though you need a flawless, single crystal."
"Oh. Is that all. I should have known." I hit the START button.