Spiral, Round Duct & Couplings

Round Offset Cut Length After Fitting Takeoff

Offset geometry gives centerline travel. Subtract the two actual fitting takeoffs to get the straight pipe cut.

Green / Field Check1stBatch 5

What This Helps With

Calculate centerline travel, then subtract fitting takeoff 1 and fitting takeoff 2. Do not subtract insertion twice.

Apprentice words: crimp end

Trade terms: crimped end, male/female, airflow direction

Check First

Confirm offset and angle. Calculate offset ÷ sin(angle). Identify both exact fittings. Verify each takeoff. Subtract both takeoffs. Dry-fit before final fastening.

What Not To Do

Do not cut to the raw triangle length, guess a universal takeoff, or subtract insertion twice.

What can go wrong: The triangle locates fitting centerlines; the fittings occupy part of that distance.

Better Foreman Question

I have a [size] round offset of ___ at ___°. I calculated ___ centerline travel, but I need the takeoff for these exact fittings before cutting the straight piece. What takeoff should I use for each end?

Open In Ask Foreman

Verify With

Reference type: foreman direction

Source to verify: Field convention; foreman

Safe wording: Use verified takeoffs for the exact fittings; the math method is universal, the dimensions are not.