Can I bend rigid in an EMT bender?

Only in the shoe made for it. A hand-bender shoe is stamped with the pipes it is for, and the stamp is the authority — read yours rather than assume. A shoe used on pipe it is not made for either dents the pipe or lets it kink, and gives a take-up that matches nothing.

Does the multiplier change for rigid?

No. The multiplier is one over the sine of the angle and the pipe has no say in it. Shrink is the same story. What changes is take-up, gain and springback, because those depend on the radius the shoe bends to and how the metal behaves.

Why does my PVC offset come out shallower than I bent it?

It cooled in a shape it had not finished taking, or it was still soft when you let go and it relaxed. Hold a heated bend to its shape until it is cool to the touch, and bend it on a template or against a mark on the floor rather than by eye — PVC has no degree scale.

Which pipe should an apprentice learn on?

Half-inch EMT. It is light, it takes a bend easily in a hand bender, it springs back little, and scrap is cheap. Every technique carries straight over to rigid; only the effort and the take-up change.

Conduit types and what bends differently

EMT, rigid, IMC and PVC all bend to the same geometry — the same multipliers, the same shrink — but each needs its own tool, its own take-up and gain, and its own allowance for springback. The first time I bent rigid after a year of EMT, the offset came out exactly right and the 90 came out 1" (25 mm) tall. That is the whole lesson of this page in one stick: the geometry of a bend does not know what the pipe is made of, and the tool figures do. Here is what stays the same from one conduit to the next, what changes, and what each one wants at the bender.

What never changes

Every number on this site that comes from an angle is the same for every conduit: the offset multiplier (1 ÷ sin θ), the shrink for each unit of rise, the centre-to-outer distance of a saddle, the spacing of a segmented bend, the roll angle of a rolled offset. A 6" (152 mm) offset at 30° needs its marks 12" (305 mm) apart whether the pipe is 1/2" EMT or 2" rigid or PVC that you shaped in a hot box. If the marks are right for one pipe they are right for all of them.

What the pipe changes is everything that depends on the radius the bend is made to and on how the material behaves while it is being bent: the take-up and gain of a 90, how much the pipe springs back, how hard the pull is, and which tool can do it at all. Those are the four columns in the table at the bottom, and none of them is a number this site can give you — they belong to your shoe and your pipe.

EMT

Thin-wall steel, the pipe most hand bending is done on. It takes a bend easily, springs back little, and a hand bender handles the small sizes — the shoe is stamped with which. Take-up is stamped on the shoe for EMT; check it against one test bend and save whichever figure the pipe in your hand actually gives. The thing EMT punishes is a pull without foot pressure: the thin wall folds instead of wrapping the shoe, and a kinked EMT bend is scrap.

Tool: hand bender in the stamped sizes; mechanical or hydraulic above.
Take-up: the stamp, verified with one test bend.
Springback: small — a degree or so past the line on most sizes.
Watch for: kinks from pulling without weight on the pedal; dents from a rigid shoe used on EMT.

Rigid and IMC

Heavy-wall threaded steel. Same trade size, larger outside diameter, much stiffer. The hand bender only bends it in a shoe made for it, and the pull is hard — a longer handle, a firmer foot, and no chance of recovering a kink. Rigid springs back noticeably more than EMT, so every bend is pulled a few degrees past its line, and an offset where one bend gets the extra and the other does not comes out with a leg that is not level. IMC sits between the two: lighter wall than rigid, bends like rigid.

The take-up is the trap. A shoe stamped for both an EMT size and a rigid size gives a different take-up on each, because the two pipes have different outside diameters and sit differently in the groove. Measure it on the pipe you are actually bending, and save it under a label that says which — "3/4 rigid, red bender" — so the calculator offers the right one.

Tool: hand bender in the stamped rigid sizes only; hydraulic or mechanical for the rest.
Take-up: different from EMT on the same shoe — a separate test bend and a separate saved row.
Springback: more — test 4 on the measure page tells you how much; it can be several degrees.
Watch for: galling of threads if you bend too close to a threaded end; the bend moving the thread engagement on a coupling.

PVC

No bender at all — PVC is heated in a hot box or with a blanket until it is soft (the heater's and the pipe maker's instructions, not a number from me; how to bend PVC conduit has the whole procedure), formed to the shape, and held there until it is cool. The geometry is identical: lay the marks out exactly as for EMT and put the bends at the marks. What is different is that there is no degree scale, no arrow, and no take-up in the bender sense. You bend to a template — a piece already bent, a line chalked on the floor, or a plywood form for a radius — and the take-up of a PVC 90 is whatever radius you formed it to.

Tool: heat and a template. Rotate the pipe in the box so it heats evenly; a flat spot on one side is a cold side.
Marks: the same layout as any conduit; the marks are where the bends start and finish, so make them long and visible — they fade in the heat.
Springback: the opposite problem — the bend relaxes if you let go warm. Hold it, or wet a rag and cool it, before you trust the angle.
Watch for: overheated pipe that kinks or whitens; a bend formed by eye that is a few degrees off, which matters as much here as on steel. Check every bend with a level against the marks.

Flex and aluminium

Flexible metal conduit is not laid out with marks at all; you route it and support it. Aluminium rigid bends in a shoe stamped for it and bends easily, with little springback, but it galls — aluminium smears onto a steel shoe and the next pipe picks it up — so the shoe is kept clean. Its take-up is its own; measure it like any other.

Shoes and sizes

A hand bender is a shoe on a handle, and the shoe is made for a range of outside diameters. Most are stamped for two pipes — an EMT trade size and a rigid trade size a step smaller, because those two have close outside diameters — and that stamp is the only rule about which pipe goes in which shoe. Above the hand-bender sizes the work moves to a mechanical bender (a ratchet or gear drive on a bigger shoe) or a hydraulic one, and those come with their own deduct charts per shoe, which you treat exactly like the stamp on a hand bender: a starting figure to check with one test bend.

What this site deliberately does not list is which trade sizes those are, what outside diameter each pipe has, or how many degrees of bend a run may carry between pull points. Sizes and radii are in your bender's own sheet; bends per run, minimum radius and support spacing are in the code book and your local amendments. The marks are geometry and belong here; the limits are rules and belong there.

Side by side

Conduit	Tool	Multipliers and shrink	Take-up and gain	Retour élastique	Note
EMT	Hand bender to the sizes the shoe is stamped for; mechanical or hydraulic above that	Same	Stamped on the shoe; verify with a test bend	Low — a degree or two	The pipe most hand bending is done on.
Rigid (RMC)	Hand bender only in a shoe stamped for it; hydraulic or mechanical for anything larger	Same	Different from EMT of the same trade size on the same shoe — measure it	Higher — pull further past the line	Heavy wall; a hard pull, and a kink is unrecoverable.
IMC	As rigid	Same	Between EMT and rigid; measure it	Moderate to high	Lighter than rigid, bends like it.
PVC	Heat: a hot box or blanket; no bender shoe	Same, once it is cool	None in the bender sense — the bend is formed, not pulled; work to a template	Relaxes while warm; hold until cool	Marks are the geometry; the shape is set by hand and eye.
Flex / FMC	None — it bends by hand	n/a	n/a	n/a	Not laid out with marks; routed and supported.
Aluminium rigid	As rigid, in a shoe stamped for it	Same	Measure it — softer than steel	Low	Bends easily; galls in a steel shoe — keep the shoe clean.

Questions

Can I bend rigid in an EMT bender?: Only in the shoe made for it. A hand-bender shoe is stamped with the pipes it is for, and the stamp is the authority — read yours rather than assume. A shoe used on pipe it is not made for either dents the pipe or lets it kink, and gives a take-up that matches nothing.
Does the multiplier change for rigid?: No. The multiplier is one over the sine of the angle and the pipe has no say in it. Shrink is the same story. What changes is take-up, gain and springback, because those depend on the radius the shoe bends to and how the metal behaves.
Why does my PVC offset come out shallower than I bent it?: It cooled in a shape it had not finished taking, or it was still soft when you let go and it relaxed. Hold a heated bend to its shape until it is cool to the touch, and bend it on a template or against a mark on the floor rather than by eye — PVC has no degree scale.
Which pipe should an apprentice learn on?: Half-inch EMT. It is light, it takes a bend easily in a hand bender, it springs back little, and scrap is cheap. Every technique carries straight over to rigid; only the effort and the take-up change.