How this calculator works
Horizontal roll and vertical set are perpendicular, so the true offset is their hypotenuse. The fitting angle connects this offset to the diagonal centre-to-centre travel. A second right triangle gives the axial run. These are centreline measurements; fitting takeouts, socket depth, weld gaps and cutting allowances are not deducted.
Formula
True offset = sqrt(roll^2 + set^2); travel = true offset / sin(angle); run = travel x cos(angle); angle = asin(true offset / travel).
Worked example
A 3 m roll and 4 m set produce a 5 m true offset. With 30 degree fittings, travel is 10 m and axial run is about 8.6603 m.
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Frequently asked questions
Is travel the cut pipe length?
No. Travel is centre-to-centre geometry. Deduct the fitting takeouts and apply the joint preparation requirements to determine a cut length.
What happens with 90 degree fittings?
The idealised travel equals true offset and axial run is zero. Actual fitting geometry still affects assembly dimensions.
Can one offset component be zero?
Yes. The other component then equals the true offset. Both cannot be zero when solving a bend or travel.