The Dow Jones Industrials (DJINDICES:^DJI) were up 19 points as of 12:30 p.m. EDT, recovering from losses earlier in Monday trading. For those tracking today's economic data that pointed to potential weakness in manufacturing and construction, gains in heavy-equipment maker Caterpillar (NYSE:CAT) and aerospace and commercial-elevator manufacturer United Technologies (NYSE:UTX) might seem unexpected. Yet a data glitch helped make investors a bit more upbeat about the prospects for the industrial economy, and pushed the Dow Jones Industrials into positive territory in the process.

Earlier this morning, the Institute for Supply Management said its report on the manufacturing sector had indicated a substantially weaker number than economists had expected, raising questions about the U.S. economy's true health. But when the ISM discovered that it had incorrectly adjusted its index for the wrong seasonal factors, the May reading for its manufacturing index rose sharply, topping expectations and painting a much different picture of the manufacturing industry.

Source: Caterpillar.

Perhaps in response, Caterpillar led all gainers in the Dow Jones Industrials, rising 1.1% by early afternoon. Construction spending also rose to its highest level since 2009, although the gain was less favorable than most market followers had anticipated. Increasingly, Caterpillar has proven to be a sharply divided business, with prospects for the construction segment looking much better than its mining equipment unit. The big question for Caterpillar is whether margins for its construction equipment segment will improve as the economy, both in the U.S. and around the world, sees faster growth. In the past, heightened competition has crimped Caterpillar's ability to extract as much profit as possible from its construction equipment sales. At some point, mining will hit rock bottom, and that could be the ultimate turning point for Caterpillar.

Meanwhile, United Technologies rose about three-quarters of a percent. Most of the interest in United Technologies as an investment lately has come from its extensive exposure to the booming aerospace industry, for which the conglomerate and Dow component supplies parts, systems, and other materials to aid in aircraft construction and maintenance. Yet often missed is United Tech's exposure to construction, as its corporate infrastructure business includes Otis elevators, UTC heating and cooling systems, and a variety of other niche areas that stand to gain when the industrial sector in general picks up.

Caterpillar and United Technologies won't lift the Dow Jones Industrials all by themselves. But even as investors get nervous about the future of the stock market, both of these Dow components are demonstrating the toughness needed to endure whatever hits them next.