Typically, when we think about forming metal parts, we think about beating them with hammers, or squeezing them with big hydraulic presses. But what if magnets could do the squeezing? As it turns out—Grumman Aerospace discovered they can, several decades ago! Even better, they summed up this technique in a great educational video which we’ve placed below the break.

The video concerns the development of the Grumman EMF Torque Tube. The parts are essentially tubes with gear-like fittings mounted in either end, which are fixed with electromagnetic forming techniques instead of riveting or crimping. Right away, we’re told the key benefits—torque tubes built this way are “stronger, lighter, and more fatigue resistant” than those built with conventional techniques. Grumman used these torque tubes in such famous aircraft as the F-14 Tomcat, highlighting their performance and reliability.

The video goes on to explain the basics of the EMF torque tube production process. A tube is placed inside a coil, with the end fitting then installed inside. A capacitor bank dumps current through the coil to generate a strong electromagnetic field. This field is opposed by a secondary field generated by eddy currents. The two forces result in an explosive force which drives the tube inwards, gripping into the grooves of the end fitting, and destroys the coil in the process. Grumman notes that it specifically optimized a grooving profile for bonding tubes with end fittings, which maximised the strength of these EMF-produced joints.

This tip was sent in by [irox]. The video itself was posted by [Greg Benoit], who notes his father Robert Benoit was intimately involved with the development of the technique. Indeed, it was useful enough that the technology was licensed to Boeing, generating many millions of dollars for Grumman.

We feature all kinds of machining and forming techniques here, but this sort of forming isn’t something we see a lot of around these parts. Still, we’re sure someone will be Kickstarting a home EMF forming machine before the end of next week.