What is a segmented bend?

A large-radius curve made from many small bends instead of one. A hand bender cannot pull a wide sweep in one shot, so you split the total angle into a series of equal bends spaced evenly along the pipe. Enough of them and the run reads as a smooth arc.

How many bends should I use?

More bends give a smoother, truer curve; fewer are quicker but show the facets. It is a trade-off, not a rule — a big-radius sweep in sight might want a bend every few degrees, while one buried in a wall can be coarser. Try a count and read the spacing and per-bend angle the calculator gives, then judge it.

What is the developed length?

The length of pipe the ideal curve uses, radius times the total angle in radians. It is how much conduit the sweep consumes between its start and end, which you need to lay out where the bends fall and to check you have enough pipe.

How do I space the bends?

Evenly, at the spacing the calculator gives, which is 2 × radius × tan(half the per-bend angle). Mark the first bend, step that spacing along the pipe for the next, and so on, bending the same small angle at each mark. Keep every bend in the same plane or the curve wanders.

Segmented bend calculator

A segmented bend fakes a large-radius sweep with a run of small equal bends. Enter the total angle of the sweep, how many bends you want to split it into, and the radius of the curve you are after; the calculator gives the angle to pull at each bend, the spacing between them, and the developed length of the ideal arc.

Worked example

Say you need a 90° sweep on a 24 inch radius, made from 9 bends. Each bend is 90 ÷ 9 = 10°. The spacing is 2 × 24 × tan(5°) ≈ 4 3/16 inches between marks. The developed length is 24 × (90° in radians) ≈ 37.7 inches of pipe through the curve. Mark the first bend, step 4 3/16 inches for each of the next eight, and pull 10° at every mark in the same plane.

The formula

The per-bend angle splits the total; the spacing comes from the chord of that small angle on the radius:

per-bend = total ÷ bends · spacing = 2 × radius × tan(per-bend ÷ 2) · developed = radius × total(rad)

Each small bend turns the pipe by the per-bend angle, and the straight length between two adjacent bends is the chord that subtends that angle on the radius, which is 2 × radius × tan of half the angle. String enough of those chords together and they trace the arc; the arc's own length, radius times the angle in radians, is the developed length you lay the marks out along.

Smoothness is a judgement, not a spec

bentright will work any bend count you give it — the right one depends on how the run will be seen and how tight the radius is. Small angles at close spacing read as a clean curve; large angles at wide spacing show the facets. There is no code number here and no single correct answer, only the geometry and your eye. Keep every bend in one plane, or the sweep corkscrews.

Questions

What is a segmented bend?: A large-radius curve made from many small bends instead of one. A hand bender cannot pull a wide sweep in one shot, so you split the total angle into a series of equal bends spaced evenly along the pipe. Enough of them and the run reads as a smooth arc.
How many bends should I use?: More bends give a smoother, truer curve; fewer are quicker but show the facets. It is a trade-off, not a rule — a big-radius sweep in sight might want a bend every few degrees, while one buried in a wall can be coarser. Try a count and read the spacing and per-bend angle the calculator gives, then judge it.
What is the developed length?: The length of pipe the ideal curve uses, radius times the total angle in radians. It is how much conduit the sweep consumes between its start and end, which you need to lay out where the bends fall and to check you have enough pipe.
How do I space the bends?: Evenly, at the spacing the calculator gives, which is 2 × radius × tan(half the per-bend angle). Mark the first bend, step that spacing along the pipe for the next, and so on, bending the same small angle at each mark. Keep every bend in the same plane or the curve wanders.

Related tools

Concentric bend calculator — several segmented sweeps kept parallel.
Conduit bending formulas — the whole reference in one place.
How to bend conduit — where segmented bends fit among the rest.