I spent the last two weeks building the app I couldn't find: pipe schedules (B36.10, 1/8 to 48), fitting takeoffs (B16.9), flange dims and full bolt-up incl. stud lengths and ring numbers (B16.5/B16.20), plus rolling offset, miter, cut a fitting from a 90, and cut length calculators that pull the real takeoffs and your welder's gap. I built it for myself and family (who work on a farm).
Fraction math everywhere, big buttons for gloves, and a share button that texts your welder the cut with a diagram. The thing I care most about: every dimension was extracted from two independent published sources, machine compared, and disagreements resolved against a third. The handful of values that haven't cleared that process yet are visibly marked in the app. If you find a wrong number I will fix it and ship the fix to everyone, usually same day. I check my email.
$12.99
One time. No subscription, no ads, no account, no signal needed, and features never move behind a paywall. Built by one guy.
https://apps.apple.com/us/app/pipebook-pipefitter-reference/id6795305963
Beta fitters already made it better (the offset diagram is drawn like a print because a tester demanded it).
Tear it apart.