PipeMaster How do you split a segmented 90° conduit bend into equal shots?
Divide 90° by however many shots you want, and that's the angle of each one. Space the marks 2 × the centerline radius × tan(half that angle) apart and you're done. The Segmented 90° calculator (Pro) does both for 1 to 20 shots at any radius — doing it by hand, it's easy to lose track by the fourth shot.
Why bend a 90 in segments
A standard 90° stub-up uses the bender's own shoe radius, which is usually small. A segmented (concentric) 90 fakes a much bigger, sweeping radius by bending a series of small partial angles along the pipe instead of one sharp curve: easier to pull wire through, and closer to the bend radius a large conduit run calls for.
The segmented 90° formula
- Segment Angle = 90° ÷ number of segments.
- Spacing Between Segments = 2 × centerline radius × tan(segment angle ÷ 2).
- Every shot bends the same angle and sits the same distance from the next one, so the run curves at a steady rate instead of all at once.
How to calculate a segmented 90 in PipeMaster
- Open Segmented 90° under Pro Calculators.
- Enter the Centerline Radius you want the finished curve to sweep.
- Set Number of Segments with the stepper, from 1 to 20.
- Read Segment Angle and Spacing Between Segments under Result.
- Mark the first shot, bend it, move along the pipe by the spacing, mark and bend the next shot at the same angle, and repeat until you have made all the shots.
Worked examples
| Centerline Radius | Number of Segments | Segment Angle | Spacing Between Segments |
|---|---|---|---|
| 6" | 6 | 15.00° | 1 19/32" |
| 8" | 4 | 22.50° | 3 3/16" |
| 4" | 8 | 11.25° | 25/32" |
| 6" | 20 | 4.50° | 15/32" |
| 150 mm | 6 | 15.00° | 39 mm |
More segments make a smoother curve but a longer run of marks and bends: 20 segments at a 6" radius need marks only 15/32" apart, which is tight for a hand bender's shoe to clear between shots.
Laying out the shots
PipeMaster gives the angle and spacing for one shot; it does not mark the pipe for you. Start the first shot a set distance from the end (enough to clear the shoe), bend it to the Segment Angle, then measure the Spacing Between Segments along the pipe for the next mark and repeat at the same angle every time.
Check the direction of each shot against the last one: rotating the pipe between shots turns the sweep into a spiral instead of a flat curve, the same mistake that ruins a two-bend offset.
Common mistakes
- Changing the angle or spacing partway through: every shot has to match, or the curve stops being a constant radius.
- Picking a shot count that puts marks closer together than your bender's shoe, so you cannot seat it for the next bend.
- Forgetting a segmented 90 still ends at 90° total: the shots add up to 90°, not more.
Limits worth knowing
- One centerline radius per bend: there is no concentric set for bending several conduits to different radii from the same run.
- The calculator gives the angle and spacing only, not where the first mark starts or the gain for the finished curve.
- Segmented 90° is part of PipeMaster Pro; the plain 90° / Stub-Up calculator is free.
Questions and answers
How many shots does a segmented 90 need?
What is the formula for a segmented 90 degree bend?
Is a segmented 90 the same as a concentric bend?
Does the segmented 90 calculator tell me where to make the first mark?
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