Conduit 90 Stub and Back-to-Back
Stub-up deduct mark, back-to-back spacing, and segmented-90 shot count.
Example
You enter
- Mode stub-up
- Stub height (in) 8
- Bender deduct/take-up 6
You get
- Mark (in) 2
Details, formula, and sources
Stub-up mark = desired height - bender deduct (take-up). Back-to-back: the far mark referenced from the near stub. Segmented 90: shot count n = ceil(90 / per-shot angle), arc per shot = radius * per-shot angle in radians.
Standard 90-degree stub-up deduct (take-up) and segment-bend geometry from the electrical apprenticeship and Ugly's Electrical References, by name. NEC Article 358 minimum radius and the four-quarter-bends-per-run limit govern.
Free read-only access to the NEC at nfpa.org/freeaccess. The deduct geometry is public first-principles math.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: mode, height_in, deduct_in, mark_in
- Deduct source user-supplied bender take-up; EMT defaults offered as a starting pointtool-specific