pipebend.py -- calculate pipe bend mark lines

Usage: pipebend.py [OPTIONS] [SEGS]...

  Print the mark lines and total length for a given bent pipe.

  SEGS is a list of pairs of segment lengths and the angle of the bends
  following them. The last angle must be zero or omitted.

Options:
  -r, --radius FLOAT          Bend inside radius.
  -d, --outer-diameter FLOAT  Pipe outer diameter.
  -w, --wall-thickness FLOAT  Pipe wall thickness.
  -k, --adj-k-factor FLOAT    K-factor adjustment.
  --help                      Show this message and exit.

SEGS is a list of numbers representing a segment length and the angle that follows. The final bend angle should always be zero. If you leave it off, zero will be added to the list automatically. To bend a 90 degree elbow with the minimum segment lengths for my shop (6" for first segment and 18" for last):

pete@foo:~/src/python/pipebend$ python pipebend.py 6 90 18
K factor: 0.18 (normal)
Centerline radius: 2.83
Cut length: 22 7/16

      Mark Angle
         3 90.0

This also assumes an inside bend radius of 2", a pipe outer diameter of 1.66", a wall thickness of 0.14" and a k-factor adjustment of +0.03663. You can specify these using the flags:

pete@foo:~/src/python/pipebend$ python pipebend.py -r 1 -d 1.315 -w 0.083 -k 0 6 90 18
K factor: 0.08 (wiper die & movable mandrel required)
Centerline radius: 1.66
Cut length: 23 1/8

      Mark Angle
     4 1/4 90.0