I've seen a few requests for information on forming & cutting tonnages etc lately. I don't know Jack Schidt about the subject but stumbled across the page below with a variety of downloadable excel spread sheets.
They may be useful to other amateurs / learners like myself.
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"Helps calculate forming & cutting tonnage, spring pressure, die clearance, die cost, thread size, perforating pressure, etc." "Standard Sheet Metal Gage Table" "Thread size tables..."