Facing the continued spread of the novel coronavirus across the US, Ford announced Tuesday that it will not resume production, as initially planned, of trucks and SUVs next week. But while the automaker’s workers aren’t stamping metal, they’re not entirely idle either. They’ve started several projects aimed at helping fight the pandemic. That means collaborating with 3M on a new respirator design using stockpiled parts like the fans made to cool the fannies of F-150 drivers. The automaker is working with GE Healthcare to increase production of ventilators, a crucial tool for Covid-19 patients struggling to breathe.

In addition, Ford designers are producing new sorts of transparent face shields to protect medical workers and first responders. It hopes to soon be making 100,000 a week at a subsidiary’s plant.

Other automakers are working on similar efforts. Tesla bought more than 1,200 ventilators in China and donated them to the public health effort in California; CEO Elon Musk said his company is looking at how to build more. General Motors is helping Ventec Life Systems scale up its ventilator production and considering other ways to help, its CEO Mary Barra says.

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“We’re just going as fast as we can,” executive chairman Bill Ford said on CNBC Tuesday. “This is what very much our company does when we’re needed.” Indeed, Ford was a key part of the “arsenal of democracy” that helped power the US to victory in World War II. At its peak, the company was building a B-24 bomber every 63 minutes at its Willow Run plant west of Detroit.

Efforts to combat Covid-19 fall far short of the contributions that Ford and other companies made to winning that war. In part, that’s because there’s no easy way to help: Just a few firms are set up for the complexity and precision of making the ventilators that patients need. But you could have said the same thing 80 years ago.

To battle Germany and Japan, American manufacturers built new factories, trained massive workforces, and stopped what they were used to doing for what needed to be done. Frigidaire made machine guns. Lingerie factories churned out camouflage netting. Road-building companies made fighting ships. Parts designed for vacuum cleaners went into gas masks.

Yes, the coronavirus calls for a different bill of munitions, on a different timescale. Health experts don’t need the same range of tools that the 1940s military demanded—ventilators and protective equipment top the list—but they need them desperately, immediately. World War II played out over years; the coronavirus has transformed life for billions in the past few weeks. American factories aren’t shut because the economy is already crippled, but because their workers must keep their distance. In 1941, most of the materials America needed to build its army lay within its borders. Today’s supply chains wrap around the globe.

Still, the way American industry mobilized for war is remarkable for its scale, speed, and success—and offers lessons for anyone trying to help today.

The first of these, sadly, isn’t much good now: Prepare well in advance. President Franklin D. Roosevelt got serious about stocking his armory (and drafting soldiers) more than a year before the Japanese attack on Pearl Harbor, soon after France fell to Germany. By April 1941, the government had ordered $1.5 billion (that’s $26.4 billion today) worth of plane engines, tanks, machine guns, and other tools just from the auto industry—the country’s great manufacturing powerhouse. By the time Congress declared war eight months later, the auto industry was well into the process of realigning supply chains and preparing to arm America. “We weren’t ready to fight in December of 1941,” says Rob Citino, the senior historian at the National World War II Museum in New Orleans, citing early losses like the fall of the Philippines. “But we were more prepared to fight than we would’ve been had Roosevelt not gotten us started early.”