Hand Bender Fundamentals: 90-Degree Stub-Ups in EMT

What Is a Stub-Up and Why It Matters

A stub-up is a 90-degree bend that turns a horizontal conduit run into a vertical rise — feeding a panel, junction box, or piece of equipment mounted on a wall. Getting the stub height right means the conduit end lands exactly where it needs to enter a knockout. Being off by even half an inch forces you to cut, re-thread, or scrap the stick. In this lab you will produce stub-ups in ½″ and ¾″ EMT that land within ±¼″ of a 10-inch finished stub height, with a true 90-degree angle and no defects.

The Hand Bender: Parts and Marks

EMT hand benders from Klein and Ideal are one-piece tools with a shoe (the curved forming surface), a hook at the toe, and a foot peg or foot tab where you apply downward pressure. Three symbols stamped or cast into the bender are your layout references:

• Arrow (▶) — the primary reference mark. When aligned to your pencil mark on the conduit, it tells the bender where the bend starts. Use the arrow for most straight stub-up work.
• Star (✱) — used for back-to-back bends and offset work. Not the focus of today's lab, but locate it so you recognize it.
• Teardrop (◉) — used to align conduit at the start of a reverse bend. Identify it on your bender and record its position relative to the arrow.

Every bender is also stamped with a take-up value — the amount of conduit the bend itself consumes, measured from the mark to the start of the curved section. For ½″ EMT this is commonly stamped as 5 inches; for ¾″ EMT it is commonly stamped as 6 inches. Always read the value off your bender because tool manufacturers and worn dies can vary slightly.

The Take-Up Concept

When you bend a 90-degree stub, the finished stub height is measured from the floor (or bottom of the conduit) to the end of the pipe after the bend. Because the bend itself uses up some length of straight pipe, you must subtract the take-up before marking.

Formula:

> Mark location = Desired stub height − Take-up value

If your target stub is 10 inches and your ½″ bender shows a 5-inch take-up, you make your pencil mark at 10 − 5 = 5 inches from the end of the conduit. Align the arrow to that mark, and when the bend reaches 90 degrees, the stub should measure 10 inches.

Step-by-Step Bending Procedure

1. Measure and mark. From the end of the stick, measure the distance equal to (stub height − take-up) and make a clean pencil line all the way around the conduit.

2. Seat the conduit in the bender. Lay the conduit in the shoe with the marked end toward the hook. Align the arrow on the bender to your pencil mark.

3. Position your body. Stand with one foot on the foot peg to anchor the bender to the floor. Your bending hand grips the conduit about 12–18 inches behind the bender; your other hand can steady the bender handle.

4. Apply smooth, steady pressure. Pull the handle toward you while pressing down on the foot peg. Move in one continuous motion — stopping and restarting can create dog-legs.

5. Read the angle. Most Klein and Ideal benders have a degree bubble or angle marks on the back of the shoe. Bring the conduit to exactly 90 degrees — verify with your combination square, not just the bubble.

6. Check stub height. Stand the bent conduit on the floor. Measure from the floor to the cut end. Record in your bending log.

7. Adjust. If the stub is short, your mark was too close to the end — move it farther from the end next time. If the stub is long, your mark was too far from the end — move it closer.

Common Defects and How to Avoid Them

• Kink — a sharp crease at the bend radius, caused by bending too fast or too far back before the shoe fully supports the conduit. Keep conduit seated deep in the shoe.
• Flattening — the conduit oval-izes at the bend, caused by excessive force or a worn shoe. Use steady, even pressure.
• Dog-leg — the conduit twists out of plane during the bend, caused by uneven side pressure. Keep the conduit aligned straight in the shoe throughout the pull.

Defective bends are not acceptable in the field because they restrict wire-pull capacity and violate NEC requirements for conduit fill and fill protection. In this lab, defective bends are cut off and the exercise is repeated.

Safety in the Bending Lab

• Safety glasses are mandatory any time you are cutting, reaming, or bending conduit. Chips and metal shards travel fast.
• Leather gloves protect your hands from sharp cut ends and the edges of the bender shoe. Remove gloves only when making pencil marks that require fine feel.
• Lockout/tagout (LOTO) is not directly applicable to hand-bending work, but you must treat cut conduit ends as sharp hazards — always de-burr and ream every cut end before handling further.
• Keep your work area clear. A 10-foot stick swinging through a 90-degree arc can strike a classmate. Announce "bending" before you pull.
• Inspect your bender before use. A cracked shoe or loose handle is a struck-by hazard; tag it out and get a replacement tool.