Bending a three-point saddle
A three-point saddle hops the conduit over something small and round, like another pipe. A center bend lifts it over the top, and two outer bends of half that angle bring it back to its line. A 45° center with 22.5° outer bends is the usual choice.
What to measure
- Obstruction height: how far the conduit has to rise to clear it, from the surface the conduit runs on to the top of the obstruction.
- Outer bend angle: the two outer bends. The center bend is twice this (Center bend).
- Distance to center of obstruction (optional): from the end of the conduit to the middle of the obstruction. With it the marks are measured from the end; without it, from the first mark.
How to bend it
- Mark all three. With a distance, mark 2 already includes Move center mark: it sits that much further from the end than the obstruction’s center, because the first half of the saddle shrinks the conduit by that much.
- Bend the center first: line mark 2 up with the center notch and bend to the Center bend angle. If the marks list says Line up with bend center, the notch is cut for another angle; use the shoe center mark for this one.
- Roll the conduit half a turn. Put mark 3 on the arrow (or on its bend center, if marks are on bend center) with the hook facing the center bend, and bend to the outer angle.
- Turn the bender round so the hook faces the center bend again, put mark 1 on the arrow, and bend it to the outer angle, the same way as mark 3.
- Sight along it: both ends should be in line and all three bends in one plane.
Where the numbers come from
On a real shoe the peak of the saddle is rounded, so the top of the conduit sits a little below the sharp corner. The calculator raises the corner by that much so the conduit still clears the full height, then treats each half like an offset.
corner height = height + R·(1 ÷ cos(outer angle) − 1)move center mark = corner height × tan(outer/2) − g(outer) − g(center)/2- Obstruction height
- 3"
- Outer bend angle
- 22.5°
- Distance to center of obstruction
- 30"
- Center bend
- 45°
- Between bends
- 7 3/8" (7 13/16" by multiplier)
- Move center mark
- 9/16" (5/8" by multiplier)
- Shrink
- 1 1/8" (1 3/16" by multiplier)
- Marks from the end
- 23 3/16", 30 9/16", 37 15/16"
If it turns orange or red
Red means the bends would run into each other: the saddle is too low for these angles on this shoe. Orange means there is too little straight between the bends for the shoe to grip. Use smaller outer bends. Red also shows when mark 1 would fall before the end of the conduit.