“Not in a way, but I'm glad Kerr authorized the extra brace. We'll use the heaviest stuff we can, and although the fastenings may give some trouble, we haven't come to them yet. Perhaps I'm getting nervous. We're up to schedule and doing pretty well, but it will be a relief to get the contract finished.”
Charnock told him about Wilkinson, and he looked thoughtful.
“I can't see his object, particularly since he left the chain alone. Of course he may have meant some mischief, but gave it up when he found you on his track.”
“Somehow I don't think that was it,” said Charnock, who went to open the door.
Kerr came in and after a time began to talk about the fastenings for the main tie-beam.
“As the rock is sound and can be thawed, I think we could use a bolt on the Lewis plan. Give me some paper and I'll make a sketch you can take to the smith.”
Charnock examined the drawing and noted that the holding part of the bolt was shaped like the letter Y, except that the stalk was split. A wedge was sketched to fit the split, and would obviously expand the upper arms to fit tightly into a fan-shaped hole with a narrow mouth.
“I've not seen this kind of fastening before,” he said. “It ought to grip well, but something depends upon the wedge.”
Kerr nodded. “The wedge must be properly forged and fit tight, but there's a cross bolt to stop it backing out. So long as it doesn't break under the hammer, it can't come loose. Something depends on the way the hole is cut and the rock, but the stuff you're working is hard enough.”
Next morning Charnock took the drawing to the smith, and calling at the forge a day or two later, found Wilkinson sitting on a box. He had brought a pick to be mended and made a few ironical remarks, until the smith showed Charnock some irons he had forged.