When you bend a tube, you run the risk of misshaping it.  The radius flattens, ripples form before the bend, buckling occurs, etc. These imperfections don’t just ruin the appearance; they hamper performance and structural integrity.

Proper bending practices and quality material can ensure a solid bend, but sometimes, additional tools are needed to retain maximum strength and shape.

To prevent excess flattening, a mandrel is often used. A mandrel is an object placed inside the tube that holds inside radius while the tube is built.

Sometimes, though, a mandrel isn’t enough. That’s when you need a wiper die.

What is a Wiper Die?

A wiper die is a metal wedge-shaped tool used for precision tube bending. At first glance, a wiper die may look more like a doorstop or crude chisel, and while it might work for the former, it’s best utilized during the fabrication process.

The top side is contoured to match the curve of a tube. The narrow end of the die is inserted between the bend die and the tube itself, adding additional support along it.

What Does a Wiper Die Do?

Whereas a mandrel provides support inside of the tube, the die adds external support. A mandrel prevents a tube from flattening, but it might not be enough to stop buckling, ripples, and humps that can form at the end of a bend’s radius.

A wiper die covers the area where these occur, forcing the tube to hold its shape, properly distributing pressure from the bend and maintaining the tube’s smooth exterior.

When to Use a Wiper Die

The need for a wiper die depends on the job. The material being used, the pressure being applied, and even the speed/cost of manufacturing can factor into the need for a wiper die. It’s best to work with an experience fabricator to determine what is needed to meet your standards and your budget.

Sometimes a wipe die is needed. Sometimes it’s not.

At Ever-Roll, we have experience in tube bending for a vast range of industries. Whether you need a little consultation, or you’re ready to place an order, we’ve got you covered. Contact us today.