Quick answer: For tight, repeatable bends in tube and pipe (roll cages, handrails, chassis, frames), get a rotary draw bender. Choose manual for occasional work and hydraulic once you bend every day or go past about 1-3/4 inch.
For big sweeping curves and arches, get a roll bender. For thin-wall tube and exhaust, where the tube must not crush, get a mandrel bender.
First: tube and pipe are measured differently
This trips up more buyers than anything else, and it decides which dies you order.
- Tube is sized by its actual outside diameter (OD) and wall thickness. 1-3/4" x .120 wall tube really is 1.75 inches across.
- Pipe is sized by a nominal size and a schedule. 1-1/2" Schedule 40 pipe is actually about 1.9 inches OD.
Dies are made for one or the other, so a tube die will not fit pipe of the same "size". Always order dies by the exact material you bend.
The three main types
| Type | How it works | Best for |
|---|---|---|
| Rotary draw | Clamps the tube to a die and pulls it around a fixed radius | Roll cages, handrails, frames, tight repeatable bends |
| Roll (ring) bender | Passes the material through three rolls a little at a time | Large radius curves, arches, circles, also angle and flat bar |
| Mandrel bender | Rotary draw with a mandrel inside the tube to stop it collapsing | Thin-wall tube, exhaust, stainless, production |
Centerline radius (CLR)
CLR is the radius of the bend measured to the middle of the tube. Each die gives one CLR. A tighter CLR looks sharper but puts more strain on the tube. As a starting point, many fabricators keep CLR at least two to three times the tube OD for thick-wall tube, and more for thin wall.
Every bender has a maximum CLR, so check it if you want large, sweeping bends on a rotary draw machine.
Manual, hydraulic or programmable?
- Manual rotary draw benders, like the Baileigh RDB-050 and RDB-100, are affordable and accurate. They get hard work on larger tube and thicker wall.
- Hydraulic benders, like the Baileigh RDB-125, RDB-150 and RDB-175 and the Edwards HAT series, do the pulling for you. Auto-stop models stop at your set angle, so every bend matches.
- Programmable benders, like the Baileigh RDB-250, RDB-325 and RDB-350-TS, store bend programs, which is ideal for production runs.
If you already own an Edwards ironworker with PowerLink, the Edwards HAT2375 and HAT1000 benders can run from the ironworker's hydraulics instead of a separate power unit.
Do not forget the notcher
Bent tube has to fit together, and that means a fish-mouth cut at every joint. A tube notcher makes those cuts in seconds:
- Hole saw notchers are the budget option.
- Abrasive belt notchers are fast and clean.
- End mill notchers are accurate and quiet.
Quick picks
Tell us the tube or pipe size, wall thickness and the radius you need, and we will match you to a bender and dies. Chat with us on the site or call (888) 990-8016.