Well, sure. If you check out the whole screamer,
you'll ruin it. So what?"

"So suppose you were going to check out a cartridge," Jayjay said.
"You don't fire it; you check each part separately. You check the
brass case. It's all right; the tests show that it won't burst under
firing pressure. You check the primer; the tests show that it will
explode when hit by the gun's hammer. You check the powder; the tests
show that the powder will burn nicely when the flame from the primer
hits it. You check the bullet; the tests show that the slug will be
expelled at the proper velocity when the powder is ignited.

"So you assume that the cartridge will function when fired.

"But will it?"

"Why wouldn't it?" Smith asked.

"Because the flame from the exploding primer can't reach the powder,
that's why!" Jayjay snapped. "Some jerk has redesigned the primer so
that the flame misses the propellant!"

"How could that happen?" Hull asked blankly.

"How? Because Designer _A_ decided that the male plug on the screamer
should have one more turn on its threads, but he forgot to tell
Designer _B_, who designs the female plug, that the two should match.
The testing equipment is designed to test each part, so each part
tests out fine. The only trouble is that the thing doesn't test out as
a whole."

* * * * *

Captain Al-Amin nodded slowly. "That's right. The test showed that the
oxyhydrogen section worked fine. It showed that the starter worked
fine. It showed that the radiowave broadcaster worked fine. But it
didn't show that they'd work together."

Smith said a short, five-letter word. It was French; the Anglo-Saxon
equivalent has only four letters. "What good does all this theorizing
do us?" he added. "The question is: How do we fix the thing?"

"Well, can't you put another turn on the thread?" Hull asked.

"Oh, sure," Smith said sarcastically. "You give me a lathe and the
proper tools, and I'll make you all the connections you want. Hell, if
I had the proper tools, I could turn us out a new spaceship, and we
could all go home in comfort."

"Couldn't you drill out the metal with that drill?" Hull asked
plaintively.

"No!" Smith said harshly. "How do you expect me to get a quarter-inch
bit into a space less than a sixteenth of an inch in diameter?"

Hull wasn't used to machinist's terms. "How big is an inch?"

"Two point five four oh oh oh five centimeters," Smith said in a nasty
tone of