Matching Centers Offset: Line Up Different Heights
Quick answer
To line up the bends of offsets with different heights, give every conduit the same run between bend centers and bend each to its own angle. By the multiplier method, tan(angle) = offset height ÷ run between bend centers. On a 10" run on a 1/2" EMT hand bender, a 6" offset takes 31.1° and a 4" offset 21.8°.
When conduits with different offset heights run side by side, bending them all at one angle puts their bends at different places along the run. To keep the bends lined up, give every conduit the same run between its bend centers and let the calculator find the angle for each height.
What to measure
- Run between bend centers: along the original line, from the center of the first bend to the center of the second. Use the same value for every conduit that has to line up.
- Offset height: this conduit’s own offset, center to center.
How to bend it
- Enter the run and the first conduit’s height, then bend it as an offset to the Bend angle shown.
- Change the height for the next conduit, keep the run, and bend it to its own angle.
- Line the first bends up by their centers: with Place marks on set to Bend center, put each conduit’s first mark the same distance from its end, with the ends lined up.
Where the numbers come from
The run between bend centers is the Offset screen’s distance between bends less its shrink (its Adjacent). The calculator solves that for the angle, rounds it to 0.1°, and works everything else out from the rounded angle.
run between bend centers = height ÷ tan(angle) + g(angle)- Run between bend centers
- 10"
- Offset heights
- 6" and 4"
- 6" offset
- 31.1°, 11 9/16" between bends, 1 9/16" shrink
- 4" offset
- 21.8°, 10 3/4" between bends, 3/4" shrink
If it turns orange or red
Red with no numbers means no angle up to 90° fits: the run is too short for that height. Otherwise the colors are the Offset screen’s at the solved angle. A tall offset on a short run needs a steep angle, which can leave too little straight between the bends; lengthen the run for every conduit if you can.
Get the marks for your bender
BendMate works this out from your bender’s radius and deduct, flags a bend that won’t work, and shows you every mark.
Common questions
What is the run between bend centers on an offset?
It is the distance along the original line from the center of the first bend to the center of the second. It equals the distance between bends less the shrink, the adjacent side of the offset’s triangle.
How do you line up the first bends of offsets with different heights?
Mark on bend centers and put each conduit’s first mark the same distance from its end, with the ends lined up. Because every conduit has the same run between bend centers, the second bends line up too.
What if a tall offset needs too steep an angle?
A tall offset on a short run needs a steep angle, which can leave too little straight between the bends for the shoe to grip. Lengthen the run for every conduit if you can.