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Remember when we had to guess on the riser height for those big steel castings?
Back at the old Johnson Foundry in Toledo, we always had trouble with shrinkage on the big gear blanks, the ones about 18 inches across. The book said to use a riser 1.5 times the section thickness, but we still got pulls. One real hot day about eight years back, I was fed up and just packed a little extra sand to make the riser a full 2 times the thickness, almost as a joke. Poured it, let it cool, and knocked it out... perfect. No sink. We ran with that for every big job after that. Anyone else find their own little number that worked better than the old rule?
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mason.drew6mo ago
Always thought the book was gospel until a similar trick saved a big pour last year.
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sandragrant6mo ago
It's funny how that works, @mason.drew. Sometimes the best tricks are the ones you learn by doing, not just by reading.
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jana5096mo ago
Ugh, tell that to my student loan debt.
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