Bending a segmented 90°
A segmented 90 builds a sweep with a much bigger radius than the shoe’s by making several small bends, called shots, evenly spaced along it. Use it to sweep around another 90 or a large obstruction.
What to measure
- Stub length: from the end of the conduit to the back of the other leg, as for a 90.
- Sweep radius: the radius you want, to the center of the conduit.
- Shots: how many bends. More shots make a smoother sweep.
- Total angle (optional): 90° unless you enter another.
- Other leg (optional): from the other end to the back of the stub. With it you get the Cut length.
How to bend it
- Mark every shot from the stub end. The marks are Between bends apart, starting at the First mark.
- Put each mark on the arrow in turn, with the hook facing the stub end, and bend it to Each shot.
- Bend every shot the same way and in the same plane, and sight along the conduit as you go.
- Check the total with a level on the stub when the last shot is done.
Where the numbers come from
each shot = total angle ÷ shotssweep length = sweep radius × total angleThe sweep starts the sweep radius plus half the OD before the back of the other leg, and each shot is centered on its share of the sweep. The first mark is the start of bend plus half a shot’s arc before the first shot’s center.
- Stub length
- 48"
- Sweep radius
- 24"
- Shots
- 6
- Other leg
- 48"
- Each shot
- 15°
- Between bends
- 6 5/16"
- Sweep length
- 37 11/16"
- First mark
- 25 3/4" (27 1/8" by multiplier)
- Marks
- 25 3/4", 32 1/16", 38 3/8", 44 5/8", 50 15/16", 57 3/16"
- Cut length
- 85"
This is the usual trade layout, and it comes out a little short. A chain of short straights and small bends sits just inside the circle it stands in for, so the stub and the leg each finish slightly low: about 1/8" with 6 shots on this 24" sweep (47 7/8" instead of 48"), and nearly 1/2" with 3 shots. Use more shots, or add that much to the stub and leg if it matters.
If it turns orange or red
Red means the stub or the leg is too short for the sweep, so a bend would run off the end of the conduit. Orange means the shots are so close together that the shoe can’t grip between them, a shot is more than the shoe is rated to bend at once, or the cut length is longer than one stick.