Measure your bender
To measure your bender, make four test bends on scrap: one 90 gives the take-up and the gain, one 45 shows where the notch really sits, and one 30 tells you the springback. Every number on this site that belongs to a tool rather than to a triangle is one you can get from a short piece of scrap in ten minutes. This page is the four test bends I do with any bender I have not used before, and a table at the bottom to keep the answers in. The calculators read the take-up from it.
Each test is one bend on a scrap and one measurement. Do them in order: take-up decides where a stub-up mark goes, gain decides how much pipe a 90 saves, the notch offset decides whether a saddle peaks where you wanted it, and springback is how far past the line you pull.
Why measure it yourself
The take-up stamped on a shoe is the maker's figure for a new shoe, a particular pipe, and an average pull. Shoes wear, EMT and rigid of the same trade size take up differently, and two people on the same bender can land apart because one lets the pipe creep before the bend starts. A chart of typical figures is worse: it is somebody else's shoe. One test bend gives you the number for your setup — and tells you how far the stamp was out — and after that every stub-up, back-to-back, kick and saddle on this site uses it.
You need: a scrap of the pipe you will actually be bending (2' 0" (600 mm) is plenty), a tape, a square or a torpedo level, a pencil, and a flat bit of floor. Do the tests on the shoe you will use, with the pull you normally use.
Each answer goes in the table at the foot of the page, one line per shoe and pipe. It stays in this browser, and the stub-up, back-to-back and kick calculators offer it back to you the next time you open them.
Test 1 — take-up, from one 90
Take-up is the length a 90 eats. The stub-up mark is the finished height less the take-up, so this is the figure that decides whether a stub lands on height.
- Mark. A line all the way round the scrap at a round figure from one end — 10" (254 mm) is easy to subtract, or 250 mm on a metric tape. Write the figure on the pipe.
- Line up. Arrow on the line, the marked end on the hook side (it becomes the stub), the long end under your foot, the way you will do it on the job.
- Bend. A full 90, pulled the way you pull: foot pressure on, steady, a touch past the line, let it relax. Check it against a square — a test bend at 88° gives you a take-up you cannot use.
- Measure. Stand the stub on the floor and tape from the floor to the back of the bend, not the inside corner. Read it to the sixteenth, or the millimetre.
- Subtract. Finished height − mark = take-up. On a 10" (254 mm) mark that stands 15 1/4" (387 mm) tall, the take-up is 5 1/4" (133 mm); on a 250 mm mark that stands 383 mm, it is 133 mm. Type it in the table below with the pipe size and the bender's name, and the stub-up calculator will offer it.
The take-up calculator does the subtraction and saves the figure in one step if you would rather do it there.
Test 2 — gain, from the same 90
Gain is how much pipe a 90 saves because it rounds the corner instead of going out to the point and back. You need it for a back-to-back bent on the arrow rather than the star, and for any run where you are adding leg lengths to see if the stick is long enough. The same scrap gives it, if you measured it first.
- Before bending (or on a fresh scrap): measure the stick end to end and write it on the pipe. Call it L.
- Bend a full 90 as in test 1.
- Measure the stub from its end to the outside corner of the bend — hold a square against the back of the stub and the back of the run and read to where they would meet. Call it A. Measure the other leg the same way: B.
- Add and subtract. Gain = A + B − L. It is a small positive number, bigger on a bigger shoe.
- Use it. On a run with a 90 in it, the pipe you need is the two legs to the corner minus the gain. It is not the correction for a missing star on a back-to-back — that is the gap between two marks on the shoe, and you get it by bending one test U on the arrow and measuring what comes out.
Test 3 — where the notch really is
The rim notch on most hand benders is meant to sit at the centre of a 45, which is why a three-point saddle lines the centre mark up on it. Some shoes put it exactly there; some are a shade off; some have no notch at all. One bend tells you which you have.
- Mark a line round a scrap at a round figure from the end, and put the line on the notch, not the arrow.
- Bend 45° — the centre bend of a saddle.
- Find the peak on the pipe. Lay it down hump-up on the floor, hold a square against the floor at the very peak of the hump, and pencil a line round the pipe where the square touches it. That puts the peak’s position on the pipe.
- Measure along the pipe from the end of the scrap to that new line, running the tape along the pipe and over the bend — not across the floor. Both legs of a 45 laid hump-up sit at 22.5° to the floor, so a floor measurement is short of the pipe by about a thirteenth of the length — 0.076 × it, if you want it exact: on the 10" (254 mm) mark above that is 3/4" (19 mm) of “notch offset” on a notch that is perfectly true.
- Compare. Peak position − mark = the notch offset. Zero means the notch is a true centre and you use it as the saddle calculator assumes. A positive figure means the peak lands that much past the mark: on a saddle, mark the centre that much short of where you want the hump, and it lands on it.
- No notch? Do the same bend with the mark on the arrow. The peak-minus-mark figure is then the arrow-to-centre distance for a 45 on this shoe; put the centre mark that much before where the hump should peak and line it up on the arrow.
Test 4 — springback
Pipe is partly elastic. Pull it to the 30° line, let off, and it sits at 28 or 29. Rigid and IMC spring more than EMT; big pipe more than small; a cold day more than a warm one. The fix is to pull a touch past the line, and this tells you how much of a touch.
- Pull a bend on scrap to exactly the 30° line — stop dead on it, no extra.
- Let off fully and take the bender away.
- Read the finished angle: a protractor, an angle finder, or a level app on the flat leg and then on the bent leg. Read it to the degree.
- Subtract. 30 minus what you read is the springback for that pipe on that shoe. Write down what you actually got; it will be bigger on rigid than on EMT and bigger cold than warm, and the only figure worth using is the one off your own pipe.
- Use it. Pull every bend that many degrees past its line. On an offset the two bends need the same treatment or the far leg is not level; on a segmented bend it is the difference between a sweep and a spiral.
Your bender table
One row per bender-and-pipe. It lives in this browser only — nothing is sent anywhere — and the take-up column is what the stub-up, kick and back-to-back calculators offer under their take-up field. Print it and it goes in the lid of the toolbox.
| Bender and pipe | Take-up | Gain | Notch | Springback |
|---|
No rows yet. Do test 1 on a scrap and type the take-up above.
Want it in your pocket? Print your bender card — one card per row of this table, with the stub-up marks already worked out from your take-up.
Questions
- Do I really need to measure it if the take-up is stamped on the shoe?
- The stamp is the manufacturer’s figure for a new shoe and an average pull. Whether it matches the tool in your hand is a question only a test bend answers — a worn shoe, a different make of pipe, or the way you personally lean on the handle all move it, and whatever it moves by lands on every stub you cut. One bend on scrap settles it for that setup, and then you save the real number.
- How often do I re-measure?
- When anything changes: a different bender, a different pipe size, a switch from EMT to rigid on the same shoe, or a stub that lands off by the same amount two jobs running. A shoe that is used every day is worth checking once a season.
- What about a mechanical or hydraulic bender?
- Same tests, same arithmetic. The take-up and gain are properties of the shoe’s radius, whatever drives it. Mechanical benders often publish a deduct chart per shoe; treat it the way you treat the stamp on a hand bender — a starting figure to check with one test bend.
- Why does bentright not just list the common take-ups?
- Because a list of somebody else’s figures is exactly what puts a stub 1/4" (6.4 mm) out. Take-up belongs to a specific shoe and pipe, and the only figure that is right is the one from the tool in your hand. The site does the subtraction; the number is yours.