The Field Guide.
Rules of thumb, bench diagnostics, and the calculators that go with them. Every entry tells you where it's from, when it breaks — and whether it's a cited fact or judgment from the bench. We lay no claim to this knowledge. We keep it sharp.
Hewn · the field guide is the free layer — it stays free · last reviewed 2026-06-24
The guide checks one number at a time. The plan adaptor checks a whole plan against your shop — your tools, your stock, your climate. That's the part that's the membership; this part never is.
Calculator engine and manual pages carried from the Bench Manual (Opus). Field notes from the Reed corpus — 1,300+ entries and counting, traced to their sources and corrected in the open.
These calculators and notes are field-tested rules of thumb compiled from the sources cited — a starting point, not a substitute for manufacturer specs or professional engineering. Verify structural and load-bearing work (shelf spans, hinge counts, joinery under load) against your own materials and conditions.