What is a rolling offset and how does this handle it?

Q: How do I calculate the cut length for a 45 degree pipe offset?

The true offset is the square root of rise squared plus roll squared, travel equals that offset divided by the sine of the fitting angle, and the cut length is travel minus the two fitting take-outs with a joint adjustment. This calculator pulls center-to-face take-out from ASME B16.9 dimensions for your elbow and pipe size and supports any angle from 0.1° to 89.9°, defaulting to the elbow’s standard bend.

Q: Why does joint type change the cut length?

Each joint type consumes pipe differently: butt-welds meet at the fitting face, socket-welds need a bottoming clearance per ASME B16.11, and threaded joints engage into the fitting per ASME B1.20.1. The calculator adjusts the cut from the bare travel-minus-take-out figure accordingly, and threaded joints let you enter a thread-engagement value (defaulting to the standard NPT engagement for the size).

Question

What is a rolling offset and how does this handle it?

Accepted Answer

A rolling offset changes both vertical and horizontal position at once, so the true offset is the diagonal of the rise and roll. Enter both Rise and Roll and the tool computes the true offset, the travel, and the roll-angle around the pipe axis you mark before fabricating. With Roll set to 0 it reduces to an ordinary flat offset.

What is a rolling offset and how does this handle it?

Answers