They talked about their adventures, but by and by Austin threw his cigarette in the stove and gave Kit the drawing-board.
“My tobacco’s not good, and the plan must be ready in the morning. Perhaps you can reckon up the rivet-holes; I own I cannot. The spacing’s even and the holes must not finish on an odd number. I get one short.”
Kit used Austin’s scale and dividers. “The holes are accurately spaced. I expect you didn’t note that the end rivet goes through the gusset-plate.”
“You have got it!” Austin agreed, and resolved to experiment, for he saw Kit knew the use of drawing-tools.
“Another thing rather bothers me, and when I get a chill I’m not very bright,” he resumed. “The drawings of the girders on the wall were made at the head office, but I’m not satisfied about the bars in tension. I don’t want to bother Wheeler; sometimes he gets annoyed.”
Kit carried the drawings to the table and was absorbed. He did not see Austin studied him, and he forgot he was the smith’s helper. He thought the plan typically American. The scheme was bold and imaginative, and the engineers did not follow old-fashioned rules. Their object was to save labor and build with speed. Kit approved, but when he examined a detail plan he knitted his brows. The fellows were bolder than he had thought and his interest carried him away.
“In tension, the ties would carry twenty-five tons to the square inch,” he said. “Your safety margin is not very large.”
“The margin is large enough. In Canada we don’t build bridges for our grandchildren. We reckon they will not have much use for locomotives like ours.”
“It’s possible,” said Kit. “All the same, your diagonal braces take some transverse strain, and you must reckon on the shearing effort across the bolts. I’d straighten three or four members. Like this——”
He got a pencil, and Austin, with some surprise, studied the sketch. He thought Kit had solved the puzzle, and he resolved to talk to Wheeler about it in the morning. Kit was not the man to stay at the forge.