Thin-Wall Tube
Low wall-to-diameter ratios wrinkle on the inside radius without inner support.
Mandrel Tube Bending
Wrinkle-Free, Round Bends On Thin-Wall & Tight-Radius Tube
A mandrel bender supports the tube bore during bending to prevent wrinkling and flattening. Here is how mandrel tube bending works and which Telhoo mandrel tube benders use it.
Quick Answer
Mandrel tube bending inserts a flexible mandrel inside the tube during bending so the wall cannot collapse — giving wrinkle-free, round bends on thin-wall and tight-radius tube. Telhoo CNC and NC benders use hydraulic moving-mandrel tooling across the Φ38–219 mm range.
The Challenge
When Mandrel Bending Is Needed
Mandrel tooling isn't always required. Use this quick guide to know when it is — and when mandrel-less is fine.
Tight Radius
Centre-line radius below about 2×D needs a mandrel plus wiper die.
Cosmetic Or Flow-Critical
Exhaust, handrail and hydraulic lines need a smooth, round bore.
Polished & Plated Finishes
Chrome, powder-coat and mirror finishes show every wrinkle, so mandrel support protects appearance.
Repeat Production Runs
On long OEM runs a mandrel keeps every bend identical and avoids scrap from wall collapse.
When You Don't Need It
Thick-wall or large-radius bends can run mandrel-less, faster and cheaper.
How Telhoo Does It
How Telhoo Implements Mandrel Bending
This is a process page, not a machine listing — but the process runs on real tooling. Telhoo benders use a hydraulic moving mandrel that supports the bore through the bend and withdraws as the tube advances, paired with a wiper die that stops wrinkles on the inside radius.
Looking for the machine itself? The mandrel tooling is built into our CNC and NC pipe benders, so every model doubles as a mandrel bending machine — whether you call it a mandrel tube bender or a mandrel pipe bender — see those ranges for specs and models.
Capacity Range
Mandrel Bending Basics
Mandrel TypesBall & Plug
Chosen by radius and wall
TubeΦ38–219 mm
Thin to medium wall
Key Partner DieWiper Die
Stops inside-radius wrinkles
Process Capability
The Tooling That Makes It Work
Each element of a mandrel set has a job in producing a clean bend on any mandrel bender.
Ball Mandrel
Linked balls support the bore through tight-radius bends.
Wiper Die
Wipes the inside radius to prevent wrinkling.
Moving Mandrel Withdrawal
The mandrel retracts in sync so the tube feeds cleanly.
Multi-Die Stacks
Stacked tooling lets one machine run several tube sizes.
Why Telhoo
A Pipe Processing Partner, Not Just A Machine
Jiangsu Telhoo has built mandrel tube bending into its CNC and NC machines for over 35 years, exporting to more than 65 countries. Our engineers match the mandrel, wiper die and speed to your tube so bends come out round and wrinkle-free.
- In-house R&D, machining and assembly
- CE, ISO9001, UL and EAC certified
- Non-standard and OEM machines built to your line
Telhoo By The NumbersZhangjiagang, China
Experience
35+
Years manufacturing pipe processing machinery
Facility
30,000 m²
Modern production plant with in-house R&D
Export
65+
Countries served across five continents
Response
24 h
Typical reply time on your quotation
In Depth
When To Use Mandrel Tube Bending — And When Not To
A quick guide to when mandrel support is essential, and when it is not.
The mandrel is a flexible tool that sits inside the tube at the point of bending. Without it, the inside radius of a thin-wall or tight-radius bend has nothing to push against, so the wall wrinkles or the section flattens. The mandrel supports the bore so the tube stays round through the bend, then withdraws as the tube advances to the next bend.
You need a mandrel when the wall is thin relative to diameter (a high diameter-to-wall ratio), when the centre-line radius is tight (roughly under 2×D), or when the bore must stay round and smooth for flow, fit or appearance — exhaust, handrail and hydraulic lines are typical. Thick-wall pipe on a generous radius can often be bent mandrel-less, which is faster and cheaper, so part of good process planning is knowing which bends actually need one.
The Telhoo Mandrel Tool Set
- Ball mandrels for tight-radius, thin-wall bends
- Plug mandrels for lighter-duty work
- Wiper dies that stop inside-radius wrinkles
- Multi-die stacks to run several tube sizes on one machine
- Hydraulic moving-mandrel tooling across Φ38–219 mm
Not sure whether your part needs a mandrel? Send the tube outside diameter, wall thickness and required radius and our engineers will advise the tooling and the right Telhoo machine to run it.
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Need Mandrel Bending Advice?
Tell us your tube and radius and we will advise whether you need a mandrel and which Telhoo machine and tooling suit.
- 1Send Your Drawing
Share your part drawing, tube size, material and quantity.
- 2Engineering Review
We confirm feasibility, tooling, layout and the right machine configuration.
- 3Tailored Quote In 24h
You receive a machine and tooling quotation, usually within one working day.
FAQ
Common Questions About Mandrel Tube Bending
Mandrel tube bending inserts a flexible or ball mandrel inside the tube during bending, supporting the bore so the wall cannot collapse. The result is a round, wrinkle-free bend on thin-wall or tight-radius tube.
Use a mandrel for thin-wall tube (high diameter-to-wall ratio), tight centre-line radius (roughly below 2×D), or cosmetic and flow-critical bends. Thick-wall, large-radius bends can often run mandrel-less.
Mandrel bending supports the bore for tight, thin-wall, high-quality bends; mandrel-less (empty) bending is faster and cheaper but limited to larger radii and heavier walls where the tube won't collapse.
Yes. Telhoo CNC and NC benders use hydraulic moving-mandrel tooling, and we match ball or plug mandrels, wiper dies and multi-die stacks to your tube and radius.
Yes — mandrel bender, mandrel tube bender and mandrel pipe bender all describe the same type of machine: a rotary-draw bender fitted with a moving mandrel. Telhoo builds this as a CNC or NC mandrel bending machine across the Φ38–219 mm range.
Our CNC and NC pipe bending machines across the Φ38–219 mm range use moving-mandrel tooling. For machine details and specs, see the CNC and NC ranges.
Custom fabrication and machines available
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