Choosing the correct tooling for tube bending (mandrels, formers, wipers)

Choosing the proper tube-bending tooling is essential to prevent deformation, ensure repeatable accuracy, and protect both your material and your machine. The right combination of mandrels, formers, and wipers depends on tube diameter, wall thickness, material strength, and bend radius. With correct tooling selection, workshops achieve cleaner bends, reduced waste, and more predictable results.

Choosing the correct tooling for tube bending starts with understanding that the machine provides the force, but the tooling provides the shape, support, and control. Every bend you produce is only as good as the former radius, mandrel support, and inner surface protection you use. When tooling is matched correctly to the tube’s material, diameter, and thickness, bending becomes predictable, consistent, and efficient.

Without the right tooling, even a high quality machine such as Tubela’s Model 3 or Model 32 cannot prevent wrinkling, flattening, or collapse during bending. Tooling is the difference between a bend that looks right and a bend that performs right under load.

Why does tooling matter so much in tube bending?

Tooling controls the flow of metal during deformation. When a tube is pulled around a former, the outer radius stretches, and the inner radius compresses. Incorrect tooling allows the material to move unpredictably, causing:

• Flattening
• Ovality
• Wrinkling on the inner radius
• Kinking
• Excessive springback
• Cracking on stainless or aluminium

Correct tooling counteracts these behaviours by supporting the metal exactly where it needs help. This is especially important when bending stainless steel, which has high tensile strength and pronounced springback, as described in Tubela’s material guidance.

What tooling is essential for clean, accurate bending?

There are four main types of tooling used in rotary draw bending:

1. Formers

The former (sometimes called a bending former) is the shaped block around which the tube is pulled around. It defines:

• Bend radius
• Cross section control
• Material flow during bending

Tubela provides a full range of formers for hydraulic machines, including:

• Tubela NB Pipe Formers for hydraulic pipe bending machines
• Tubela NB.HD 5D Pipe Former for hydraulic Pipe bending machines
• Tubela NB.HD Pipe Former for hydraulic pipe bending machines
• Tubela OD.HD Pipe Bending Formers

The radius and size of the former must match the tube diameter and the required bend.

2. Mandrels

Mandrels support the tube internally, preventing collapse during tight radius or thin wall bending. They are essential when:

• Bending aluminium
• Bending stainless steel
• Producing bends tighter than 3 times the tube diameter
• Maintaining roundness for precision assemblies

Mandrels come in different forms:

Without mandrel support, tubes are far more likely to wrinkle, flatten, or distort.

3. Wipers

Wipers prevent material from gathering on the inside radius of the bend. They are positioned behind the tube to smooth out compression wrinkles. They are essential when:

• Using thin wall materials
• Producing tight radius bends
• Working with stainless steel or aluminium
• Accuracy is essential

Wipers help the metal flow cleanly, especially when mandrels are also used.

4. Clamps and support tooling

Correct fit up and material handling prevent errors before bending begins. Tools such as:

Tubela Piranha Tube Notcher

Tubela Plane of Bend Clamp

Ensure correct alignment and preparation for welding or multi-part assemblies.

How do you choose the correct former for your bend?

Choosing the right former depends on three things:

1. Tube diameter

The former must match the tube exactly. Even a small mismatch creates ovality or slipping.

2. Wall thickness

Thin walled tubing requires larger radii and may need mandrel support.

3. Minimum bend radius

Bend radius is expressed as a multiple of the tube diameter.
 For example:
 • 1D radius = very tight bend
 • 2D radius = standard tight radius
 • 5D or 6D radius = sweeping, gentler bend

Tubela offers a complete range of radii across its hydraulic tooling sets.

What happens if tooling is not matched correctly?

Incorrect tooling is the number one cause of bend failure.

Common problems caused by incorrect tooling:

Correct tooling eliminates these issues entirely, making bending predictable rather than trial-and-error.

Choosing tooling for Model 3 and Model 32

Tubela’s hydraulic machines are designed with flexible tooling compatibility.

Tubela MODEL 3 Tube Bender

 Ideal tooling includes:
 • Standard radius formers
 • Light to medium duty mandrels
 • Wipers for aluminium and stainless
 • Compatible with pro and starter kits:

Tubela MODEL 3 Tube Bender Starter Kit

Tubela MODEL 3 Tube Bender Professional Kit

Model 3 is ideal for smaller workshops or those working with mild steel and lighter fabrication projects.

Tubela MODEL 32 Tube Bender

 Suitable for:
 • High strength materials
 • Thick wall tubing
 • Tight radius bends with tooling support
 • Heavy duty mandrels and wipers
 • Starter and pro kits available:

Tubela MODEL 32 Tube Bender Starter Kit

Tubela MODEL 32 Tube Bender Professional Kit

Model 32 benefits most from structured tooling setups due to its higher capacity and use with performance materials.

How material selection influences tooling choice

As described in Tubela’s material guidance, aluminium and stainless steel require careful handling due to deformation, ductility, and springback characteristics.

Aluminium

• High ductility
• Easily deforms without support
• Benefits greatly from mandrels and wipers

Stainless steel

• Strong and springy
• Needs hydraulic or electric force
• Mandrels reduce cracking and ovality

Mild steel

• Forgiving
• Works well with standard formers
• Good for beginner tooling setups

Chromoly

• High strength
• Perfect for motorsport and structural components
• Requires quality former alignment and consistent hydraulic pressure

How lubrication, setup, and maintenance affect tooling performance

From Tubela’s safety and maintenance guidance, lubrication and inspection significantly extend tooling life and prevent costly damage to machines and materials.

Recommended practices include:

• Lubricating mandrels and wipers before bending
• Ensuring former surfaces are clean and undamaged
• Inspecting for wear on mandrel balls
• Aligning tubing correctly in the clamp
• Checking hydraulic levels and pressure for consistent force
• Inspecting formers for cracks or distortion

Tooling lasts significantly longer and produces better results when maintenance routines are followed.

Tooling selection table

What are the biggest tooling mistakes workshops make?

1. Using the wrong radius former

Too tight a radius for the material leads to collapse or wrinkling.

2. Skipping mandrels to save time

This almost always results in tube distortion during tight bends.

3. Using worn tooling

Minor imperfections result in visible bend defects.

4. Incorrect lubrication

Dry bending increases friction and causes surface damage.

5. Mixing incompatible tooling brands

Poor fit between former, mandrel, and wiper creates misalignment.

Correct tooling is not an optional upgrade. It is the foundation of accurate bending.

FAQ: Choosing tooling for tube bending

1. How do I know which former radius to choose?

Match the bend requirement to the radius, usually expressed as a multiple of the tube diameter.

2. When is a mandrel essential?

Whenever the bend radius is tight, or the tube wall is thin, especially with aluminium or stainless steel.

3. Can I bend stainless steel without a mandrel?

Possible on larger radii, but a mandrel significantly improves quality and reduces cracking.

4. Are mandrels only for hydraulic or electric benders?

No. Mandrels can be used on manual machines if the setup supports it, though hydraulic systems produce better results.

5. Why do bends wrinkle on the inside radius?

Lack of wiper support or incorrect mandrel placement.

6. Should tooling match the exact diameter of the tube?

Yes. Incorrect sizing causes ovality and slipping.

7. How often should tooling be inspected?

Daily for workshop environments, following Tubela’s maintenance guidance.

8. What is the best tooling for motorsport roll cages?

Heavy duty formers with correct radius selection and quality material.

9. Do I need different tooling for aluminium?

Yes. Aluminium deforms easily and requires good mandrel and wiper support for tight bends.

10. Can poor tooling damage my machine?

Yes. Misalignment and excessive force cause unnecessary strain on hydraulic systems.

If you want expert guidance on selecting the right tooling for your tube-bending projects, Tubela’s technical specialists can recommend the appropriate formers, mandrels, wipers, and support tools for your machine and materials.

Call Tubela Engineering on 01371 859 100
Email: [email protected]
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