Common Conduit Bending Mistakes and How to Avoid Them
By Andrew ·
Quick answer
The most common conduit bending mistakes are forgetting the take-up on a 90, forgetting shrink on an offset, facing the hook the wrong way, rolling the conduit by the wrong amount, and using a head that does not match the conduit. Most can be avoided by marking every bend before bending, testing on scrap, and checking each bend before the next.
Mistakes in measuring and marking
- Forgetting the take-up. Marking a 90 at the stub length instead of stub minus take-up.
- Forgetting shrink. An offset or a saddle shortens the run, and conduit cut to length ends up short.
- Measuring to the wrong place. The stub is measured to the back of the bend, not to the inside.
- Mixing methods. Marking some bends for the arrow and some for the center, then bending them all on the arrow.
- Wrong head. The take-up for a 3/4" head used on 1/2" conduit, or EMT numbers on rigid.
Mistakes at the bender
- Hook the wrong way. The bend lands somewhere else, or the stub comes out the wrong side.
- Rolling the wrong amount. An offset needs a half turn between bends. Less than that gives a dogleg, and more makes a twist.
- Pulling off-plane. A handle that leans sideways twists the conduit and can kink thin wall.
- Stopping at the wrong angle. The conduit springs back a little, and not checking leaves the bend under.
- Bending before marking. Losing count of the marks halfway through.
Mistakes on saddles, kicks and racks
- Saddle center bend made to the wrong angle. It should be twice the outer bends’ angle, and bent first.
- Kick marked from the front of the 90 instead of its back.
- A rack marked alike. When the bends are in the rack’s plane, each conduit’s marks move along to keep the spacing.
- One set of marks for different sizes. Each shoe has its own take-up and radius.
Symptoms, causes and fixes
| What you see | Likely cause | Fix |
|---|---|---|
| Stub is too long | Take-up not subtracted, or the bender takes up more than the number used | Test on scrap and correct the take-up |
| Stub is too short | Take-up subtracted twice, or the bender takes up less than the number used | Test on scrap and correct the take-up |
| Offset ends short | Shrink forgotten | Add the shrink to the cut length |
| Legs are not parallel | Bends at different angles, or not in the same plane | Check each angle with a level and keep a line on top |
| Dogleg | Conduit not rolled a full half turn between the bends | Draw a line along the pipe and roll it exactly half a turn |
| Kink | Wrong head, or off-plane pull | Cut it out and start again with the right head |
| Bend is under | Springback | Overbend a little and check |
A worked example: the 90 that came out long
- Stub wanted
- 12"
- Mark used
- 12"
- Take-up
- 5"
- Mark should have been
- 7"
- Stub you get
- 17", which is 5" too long
The fix is simple, but the stick is spoiled. Writing “stub − take-up” on the conduit as you mark it costs a second and saves the stick.
A checklist before every bend
- Is the head right for this conduit and size?
- Is every mark made, numbered and measured from the same end?
- Which way does the hook face for this bend?
- Is the take-up or shrink allowed for?
- After the bend: angle, plane and length checked before the next one?
A bend that is a few degrees off can often be nudged back with the same head. A kink or a flattened wall cannot be fixed, so cut it out.
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 most common mistake in conduit bending?
Forgetting to subtract the take-up on a 90, or the shrink on an offset. Both come from marking the job’s dimensions straight onto the conduit.
Why is my 90 bend too long or short?
The bender’s real take-up differs from the number you used. Bend a scrap, measure the stub, and correct the take-up by the difference.
What causes a dogleg in an offset?
The conduit was not rolled a full half turn between the two bends, so the legs are out of line. A line along the top makes it easy to see.
Can you fix a kinked conduit?
No. A kinked or flattened section is weak. Cut it out, or start with a new piece.