About bentright

bentright does one thing: it works the marks for a bend in a piece of pipe. Offsets, saddles, stub-ups, rolled offsets — one calculator per bend, each on its own page, built to be read on a phone at the bender rather than at a desk, in inches or millimetres — whichever your tape reads.

Where the numbers come from

Every result is trigonometry. An offset multiplier is one over the sine of the angle; shrink is the difference between the hypotenuse and its run. None of it is copied from a code book, because none of it needs to be — the geometry of a bent pipe is the same in every edition of every code, and it does not go stale. The formula is shown openly on each page so you can check the tool against your own head.

What it does not do

It does not size anything, it does not carry a take-up chart, and it does not reproduce tables from any code book — not the Canadian Electrical Code, not the NEC, not a local amendment. The site is deliberately code-agnostic: every figure it uses comes from geometry or from you. Take-up is a property of your bender and is stamped on the tool; you type it in, and the site does the subtraction. Anything that would produce a design, a load, or a capacity is deliberately out of scope — a wrong bend wastes a stick of pipe, and that is the worst this tool can cost you.

What is actually on the site

Two halves. A calculator for each bend, each with the procedure at the bender underneath the number — and a set of reference pages for the things a calculator cannot answer.

The calculators

Start with the offset: it is the bend everything else is built from, and the page is the template for the rest. From there, three-point and four-point saddles for going over things, the stub-up and back-to-back for 90s, rolled offsets when the run has to move two ways at once, and parallel and concentric for a rack.

Every one shows its formula, redraws a dimensioned diagram as you type, and prints to a bend sheet you can tape to the bender.

The reference

Bending, from zero if this is week one. Measure your bender to get take-up, gain and springback for the tool in your hands rather than a chart. Common mistakes and what an inspector looks for are the same faults from two directions.

Then the quick ones: the cheat sheet, the multipliers, tape fractions and the glossary.

Who it is for

An apprentice who has been handed a bender and a stick of half-inch and told to make it fit. A journeyman who knows the bend cold but wants the sixteenth read back rather than worked out on a scrap of drywall. Anybody whose phone is the only thing in reach that can do arithmetic, with one glove off, in bad light.

That is why the answers are tape fractions first and decimals second, why the buttons are thumb-sized, why the number is never below the fold, and why nothing asks you to sign in to use it.

Check it against your own head

Do not take a calculator's word for anything you are about to cut. Two habits make that cheap:

Sanity-check the shape. The distance between marks is always bigger than the rise, and the shallower the angle the bigger it gets. If a 10° offset gives you a distance close to the rise, something is wrong with the input, not the trigonometry.
Open the working. Every offset-family result has a "show the working" fold that substitutes your numbers into the formula, line by line. If the site and your head disagree, that fold shows which step you differ on.
Test-bend once per bender. The one figure the site cannot know is what your tool does to your pipe. Measure it once, write it on the bender, and every mark after that is yours rather than an average.

How it is built

Static pages and one small script per calculator. Every bend is worked out in your browser from what you type — nothing you enter is sent anywhere — which keeps the site fast and means it should still work years from now without anyone touching it.

A few things are kept in your browser's own storage so the site remembers you between visits: whether you work in imperial or metric (bentright.system and bentright.system.src, with the older bentright.unit kept in step), a tally of which calculators you open so your most-used can come first (bentright.recent), any take-ups you save (bentright.takeup), your bender table from measure your bender (bentright.bender), the address you last emailed results to (bentright.sendto — the site sends that one email through its mail provider and keeps the address only if you tick the list box), and a random id so return visits can be counted (bentright.vid). Clearing your site data clears the lot. There is also an optional email list and, if you sign in, an account that syncs those preferences — nothing on the site needs it. Privacy is the full account.

A few things are kept in your browser's own storage so the site remembers you between visits: whether you work in imperial or metric (bentright.system and bentright.system.src, with the older bentright.unit kept in step), a tally of which calculators you open so your most-used can come first (bentright.recent), any take-ups you save (bentright.takeup), your bender table from measure your bender (bentright.bender), the address you last emailed results to (bentright.sendto — the site sends that one email through its mail provider and does not keep the address), and a random id so return visits can be counted (bentright.vid). Clearing your site data clears the lot. If you sign in, an optional account syncs those preferences — nothing on the site needs it. Privacy is the full account.