SOUTHFIELD, Mich. – The last time U.S. factory workers put in longer weeks than they averaged in February, Rosie the Riveter was on the assembly line and American GIs were fighting Nazis in Europe.

All those extra hours helped to drive five straight months of manufacturing growth in the United States, racking up 52,000 new factory jobs, according to Labor Department data. That includes 14,000 positions in February alone.

“The workweeks are very, very, very long right now, on a historical basis,” said Michael Montgomery of IHS Global Insight. “That’s why you’re seeing job growth in manufacturing. When you have to start to pay people time and a half, and you have the volume of business, you can justify hiring people.”

The strongest U.S. auto industry since 2007 is benefiting companies such as American Axle & Manufacturing Holdings, which by year-end will add 400 more people at one of its Michigan factories.

Transportation and metal fabrication industries make up a majority of the job gains since September as auto sales rebounded more quickly than housing from the U.S. recession that ended in 2009.

With housing and other industries starting to join autos in supporting manufacturing, the job gains are looking more sustainable, Montgomery said.

New-home sales jumped in January to the highest level since July 2008 as buyers took advantage of mortgage rates close to all-time lows, Commerce Department data showed on Feb. 26.

Production workers averaged 41.9 hours a week in February, Labor Department data showed last week. That tied December 1997 and January 1998 as the most since May 1944, when full wartime production was pulling more women into factories, as symbolized by the Rosie the Riveter character in posters, song and film.

The record was 45.4 hours in January and February 1944.

If the demand stays steady, employers will be forced to considering hiring for future needs, not just for immediate openings, said John Challenger of Challenger Gray & Christmas, an employment consulting firm based in Chicago.

“This has been the classic start-and-stop recovery, so people were reluctant to hire,” Challenger said. “We are seeing a surge right now. As employers say ‘It’s costing us too much, we’re losing talent, other companies may get the talent before we do, so we better get out in front of this,’ that leads to more hiring.”

Supporting the notion, the Labor Department said Tuesday that employers in January fired the fewest workers since it started tracking the data 12 years ago, while job openings rebounded.