90-degree stub-up calculator
A stub-up is a single 90° bend to a set height. Enter the finished height you want to the back of the bend and the take-up stamped on your bender; the calculator gives the mark to measure from the end of the pipe. Line the bender arrow up with that mark and bend up. If you have measured your own take-up on the take-up page and saved it, it is offered under the field.
On the bender
The first bend everybody learns, and the one that teaches you to trust the take-up. One mark, one pull.
- Measure. Decide the finished height to the back of the 90 — floor to the back of the bend when it stands up. Read the take-up off the shoe for this pipe size, or use your own saved figure.
- Mark. From the end of the stick, measure height minus take-up and draw a line right round the pipe. That is the only mark.
- Line up. Pipe on the floor, bender on the pipe with the hook toward the end you measured from — that end becomes the stub. Slide until the arrow is on the line.
- Bend. Foot pressure down on the pedal, one steady pull on the handle until the pipe stands square; a touch past 90 and let it relax back. Do not pull the handle without weight on the foot — the pipe lifts out of the groove and kinks.
- Check. Stand the stub on the floor, tape from the floor to the back of the bend. If it is tall by 1/4" (6.4 mm), your real take-up is that much more than the figure you used: fix the figure, not the method, and save it on the take-up page.
Worked examples
A 12" (305 mm) stub, take-up 5
Say you want a 12" (305 mm) stub and your bender is stamped 5 for that pipe (5" (127 mm)). The mark goes 12 − 5 = 7" (178 mm) from the end. Hook the pipe, slide the arrow to your 7" (178 mm) mark, and pull the bend to 90°. The back of the finished bend sits 12" (305 mm) up. The take-up is what the curve ate; the mark is the height minus that.
A 300 mm stub, metric job
A metric drawing wants the back of the 90 at 11 13/16" (300 mm), and you have measured your bender's take-up for this pipe at 125 mm (4 15/16" (125 mm)) with a test bend. The mark goes 300 − 125 = 6 7/8" (175 mm) from the end. Arrow on it, pull the 90, and the back lands at 300. Same subtraction, same tape — only the numbers on it change.
A 4' 6" (1372 mm) stub up a wall, in feet and inches
A run comes up out of the floor and has to turn into a panel whose bottom
knockout is 4' 6" (1372 mm) up. Say the bender for this pipe is stamped 8. Type
4' 6" and the calculator reads 54" (1372 mm); the mark goes
54 − 8 = 46" (1168 mm) from the end, which is 3' 10" (1168 mm) on the
tape. The stub is tall, so the arithmetic is easy and the line is what
matters: draw it all the way round the pipe, because from behind the bender
a mark on the far side is invisible.
A short stub into a box, with a fraction in it
The box knockout centre is 10 3/4" (273 mm) off the floor and say your bender is stamped 5 1/4. Mark at 10 3/4 − 5 1/4 = 5 1/2" (140 mm) from the end. Short stubs are where a wrong take-up shows most: 1/4" (6.4 mm) tall on a 4' 0" (1219 mm) stub is nothing, on a 10" (254 mm) stub into a box it is a connector that will not seat.
Two stubs, one stick
You need a 14" (356 mm) stub at each end of the same piece, 5' 0" (1524 mm) between the backs. This is a back-to-back, but the first bend is this page's stub: 14 − 5 = 9" (229 mm) from the end, arrow on the mark. Bend it, and the second bend goes 60" (1524 mm) further along, off the star. Every multi-bend piece starts with a stub worked this way.
Try one — a stub-up
Work it on paper, then type the marks. A sixteenth either way counts — that is as close as a tape reads. Two millimetres either way counts.
Loading a bend…
Escriba pulgadas como 12, 1 5/8 o 1' 3 1/2".
What went wrong
Every stub is tall (or short) by the same amount
What you see: each one finishes, say, 1/4" (6.4 mm) over the height you asked for, stub after stub.
Why: the take-up figure is wrong by that 1/4" (6.4 mm) for this bender and this pipe. The method is fine; the number on the shoe (or the one you remembered) is not.
Fix: correct the figure, not the technique. Tall by 1/4" (6.4 mm) means the real take-up is that much more than you used. The take-up page works it out from any bend you have already made, and saves it so this calculator fills it in.
The stub is off by a wildly different amount
What you see: one stub is right, the next is inches (tens of millimetres) out.
Why: the mark was measured from the wrong end, or the pipe went in the shoe with the free end the wrong way. The mark and the arrow are correct; what stands up is the wrong piece of pipe.
Fix: the free end — the one that will be the stub — points away from you, past the hook. Measure the mark from that end. Always the same end, always the same way round.
Right height, wrong angle
What you see: the stub measures right but leans a few degrees off the wall.
Why: the pull stopped on the 90 mark and springback took it back to 87 or 88, or the pipe was not seated in the shoe so the last few degrees bent a kink instead of a curve.
Fix: foot pressure on, steady pull, and a touch past the mark — how much past is a feel you get from the first two scraps with a given pipe. Check it against something square before you bend the next one.
The formula
The mark from the end is the finished height less the take-up:
marca = altura − take-up
Everything above the bender arrow becomes the vertical leg. The bend does not turn a sharp corner — it sweeps a radius — and take-up is the length that sweep uses up. Subtract it and the leftover is exactly the height you asked for. That is why the figure lives on the tool: it is a property of that bender's radius, not of any code book.
Take-up is on the tool, not in a table
bentright does not host a take-up chart. The number is stamped on the bender shoe and it changes with the make of bender and the size of pipe, so the only right value is the one on the tool in your hand. If you have lost it, bend a scrap to a known mark, measure the finished height, and the difference is your take-up for that setup.
Which bender these numbers assume — and how to adjust
The geometry belongs to the angle, not the tool. What the tool changes — its reference marks, its take-up and gain, its springback — is yours to read off the shoe or prove on scrap, never a table here (the four test bends). For this bend:
The mark goes on the arrow with the end you measured from on the hook side, and the take-up you typed is the figure for this shoe and this pipe size. That is the whole dependence: a different make of bender, a different pipe size, a worn shoe or an aggressive pull all move the take-up, and nothing on this page can know which one you hold. Read it off the shoe, or better, prove it with one test bend on the take-up page and save it — it fills in here.
Preguntas
- What is take-up on a conduit bender?
- Take-up is how much length the bend itself consumes as the pipe curves through 90°. It depends on the bender and the pipe size, and it is stamped on the bender shoe or printed in the tool sheet. Read yours and enter it — it is not a code figure, and guessing it is the usual reason a stub comes out the wrong height.
- Where do I measure the mark from?
- From the free end of the pipe — the end that becomes the top of the stub. Measure the mark back from that end, line the bender arrow up with the mark, and bend up. The height from the floor to the back of the 90 is then your finished height.
- Why is my stub-up too tall or too short?
- The take-up is wrong or the mark was measured from the wrong end. If every stub is off by the same amount, your take-up figure is off by that amount — remeasure a known bend to find the real take-up for that bender and pipe.
- Does take-up change with pipe size?
- Yes. A bigger radius consumes more length, so a larger conduit has a larger take-up on the same style of bender. That is why the figure is stamped per size on the tool rather than being a single number. Enter the one for the pipe in your hand.